@article {pmid31605761,
year = {2019},
author = {Parai, D and Banerjee, M and Dey, P and Mukherjee, SK},
title = {Reserpine attenuates biofilm formation and virulence of Staphylococcus aureus.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {103790},
doi = {10.1016/j.micpath.2019.103790},
pmid = {31605761},
issn = {1096-1208},
abstract = {This study investigated the effects of reserpine, the main bioactive compound of Rauwolfia serpentina, on biofilm formation and biofilm-associated virulence factors production in a Gram-positive pathogen, Staphylococcus aureus. Crystal violet assay, MTT assay, Congo red binding, CLSM studies were performed to assess the antibiofilm activity. Molecular docking was performed to explain the possible mode of action, catheter model was used to evaluate its application potential and the combinatorial study was performed in search of an improved therapeutic formulation. Reserpine affects biofilm formation, EPS production, biofilm cell viability and virulence factor production. It could eradicate 72.7% biofilm at ½ × MIC dose and could also stop the metabolic activity of 50.6% bacterial cells in a biofilm. Staphylococcus aureus biofilm- and virulence-regulatory proteins like AgrA, AtlE, Bap, IcaA, SarA and SasG were found to interact with reserpine which might lead to the attenuation of its pathogenicity. Reserpine along with other commercial antibiotics could generate a hightened antibiofilm response and could also eradicate a good percentage of bacterial biofilm from a urinary catheter model. These findings suggested reserpine as a good alternative entity to generate new improved therapeutic formulations.},
}
@article {pmid31605708,
year = {2019},
author = {Dai, L and Wu, TQ and Xiong, YS and Ni, HB and Ding, Y and Zhang, WC and Chu, SP and Ju, SQ and Yu, J},
title = {Ibuprofen-mediated potential inhibition of biofilm development and quorum sensing in Pseudomonas aeruginosa.},
journal = {Life sciences},
volume = {},
number = {},
pages = {116947},
doi = {10.1016/j.lfs.2019.116947},
pmid = {31605708},
issn = {1879-0631},
abstract = {AIMS: Pseudomonas aeruginosa is one of the leading causes of opportunistic and hospital-acquired infections worldwide, which is frequently linked with clinical treatment difficulties. Ibuprofen, a widely used non-steroidal anti-inflammatory drug, has been previously reported to exert antimicrobial activity with the specific mechanism. We hypothesized that inhibition of P. aeruginosa with ibuprofen is involved in the quorum sensing (QS) systems.<br><br>MAIN METHODS: CFU was utilized to assessed the growth condition of P. aeruginosa. Crystal violent staining and acridine orange staining was used to evaluate the biofilm formation and adherence activity. The detection of QS virulence factors such as pyocyanin, elastase, protease, and rhamnolipids were applied to investigation the anti-QS activity of ibuprofen against P. aeruginosa. The production of 3-oxo-C12-HSL and C4-HSL was confirmed by liquid chromatography/mass spectrometry analysis. qRT-PCR was used to identify the QS-related gene expression. Furthermore, we explored the binding effects between ibuprofen and QS-associated proteins with molecular docking.<br><br>KEY FINDINGS: Ibuprofen inhibits P. aeruginosa biofilm formation and adherence activity. And the inhibitory effects of ibuprofen on C4-HSL levels were concentration-dependent (p < 0.05), while it has no effect on 3-oxo-C12-HSL. Moreover, ibuprofen attenuates the production of virulence factors in P. aeruginosa (p < 0.05). In addition, the genes of QS system were decreased after the ibuprofen treatment (p < 0.05). Of note, ibuprofen was binding with LuxR, LasR, LasI, and RhlR at high binding scores.<br><br>SIGNIFICANCE: The antibiofilm and anti-QS activity of ibuprofen suggest that it can be a candidate drug for the treatment of clinical infections with P. aeruginosa.},
}
@article {pmid31603038,
year = {2019},
author = {Mugge, RL and Lee, JS and Brown, TT and Hamdan, LJ},
title = {Marine biofilm bacterial community response and carbon steel loss following Deepwater Horizon spill contaminant exposure.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-13},
doi = {10.1080/08927014.2019.1673377},
pmid = {31603038},
issn = {1029-2454},
abstract = {Steel marine structures provide foci of biodiversity when they develop into artificial reefs. Development begins with deposition of a biofilm. The effects of contaminants from oil spills on biofilm microbiomes, microbially-induced corrosion (MIC) and metal loss may impact preservation of marine metal structures. A microcosm experiment exposed biofilms on carbon steel disks (CSDs) to crude oil, dispersant, and dispersed oil to address their impacts on bacterial composition and metal loss and pitting. Biofilm diversity increased over time in all exposures. Community composition in dispersant and dispersed oil treatments deviated from the controls for the duration of a 12-week experiment. As biofilms matured, Pseudomonadaceae increased while Rhodobacteraceae decreased in abundance in dispersed oil treatments compared to the controls and dispersant treatments. Greatest mass loss and deepest pitting on CSDs were observed in dispersed oil treatments, suggesting impacts manifest as a consequence of increased MIC potential on carbon steel.},
}
@article {pmid31602310,
year = {2019},
author = {Rupel, K and Zupin, L and Ottaviani, G and Bertani, I and Martinelli, V and Porrelli, D and Vodret, S and Vuerich, R and Passos da Silva, D and Bussani, R and Crovella, S and Parsek, M and Venturi, V and Di Lenarda, R and Biasotto, M and Zacchigna, S},
title = {Blue laser light inhibits biofilm formation in vitro and in vivo by inducing oxidative stress.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {29},
doi = {10.1038/s41522-019-0102-9},
pmid = {31602310},
issn = {2055-5008},
abstract = {Resolution of bacterial infections is often hampered by both resistance to conventional antibiotic therapy and hiding of bacterial cells inside biofilms, warranting the development of innovative therapeutic strategies. Here, we report the efficacy of blue laser light in eradicating Pseudomonas aeruginosa cells, grown in planktonic state, agar plates and mature biofilms, both in vitro and in vivo, with minimal toxicity to mammalian cells and tissues. Results obtained using knock-out mutants point to oxidative stress as a relevant mechanism by which blue laser light exerts its anti-microbial effect. Finally, the therapeutic potential is confirmed in a mouse model of skin wound infection. Collectively, these data set blue laser phototherapy as an innovative approach to inhibit bacterial growth and biofilm formation, and thus as a realistic treatment option for superinfected wounds.},
}
@article {pmid31600988,
year = {2019},
author = {Bardhan, T and Chakraborty, M and Bhattacharjee, B},
title = {Bactericidal Activity of Lactic Acid against Clinical, Carbapenem-Hydrolyzing, Multi-Drug-Resistant Klebsiella pneumoniae Planktonic and Biofilm-Forming Cells.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {8},
number = {4},
pages = {},
doi = {10.3390/antibiotics8040181},
pmid = {31600988},
issn = {2079-6382},
support = {Ramanujan Fellowship; SB/S2/RJN-013/2014//Science and Engineering Research Board/ ; },
abstract = {: Carbapenem resistant Klebsiella pneumoniae has been highlighted to be a critical pathogen by the World Health Organization. The objectives of this study were to assess the efficacy of lactic acid (LA) against planktonic cells and biofilms formed by carbapenem-hydrolyzing K. pneumoniae isolates obtained from the nares of preterm neonates. Time-kill assays with graded percentages of (v/v) LA in water were initially carried out against planktonic cells of a meropenem (MRP)-resistant K. pneumoniae isolate, JNM11.C4. The efficacy parameters such as optimal incubation time and minimum inhibitory concentration were determined by comparing colony-forming unit counts (log(10)CFU). Scanning electron microscopy was used to visualize cell damage. Likewise, JNM11.C4 biofilms were treated with graded series of (v/v) LA. Six carbapenem-hydrolyzing isolates were next used to validate the results. A reduction of 3.6 ± 0.6 log(10) CFU/mL in JNM11.C4 planktonic cells and >3 ± 0.03log(10) CFU/mL in biofilm-forming cells were observed using 0.225% and 2% LA, respectively, after three hours. Similar decreases in viable cell-counts were observed both in the case of planktonic (˃3.6 ± 0.3log(10) CFU/mL) and biofilm-forming cells (3.8 ± 0.3log(10) CFU/mL) across all the six clinical isolates. These results indicate that LA is an effective antimicrobial against planktonic carbapenem-hydrolyzing K. pneumoniae cells and biofilms.},
}
@article {pmid31599377,
year = {2019},
author = {Bakraoui, M and Hazzi, M and Karouach, F and Ouhammou, B and El Bari, H},
title = {Experimental biogas production from recycled pulp and paper wastewater by biofilm technology.},
journal = {Biotechnology letters},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10529-019-02735-w},
pmid = {31599377},
issn = {1573-6776},
support = {413223920433//University Ibn Tofail/ ; },
abstract = {OBJECTIVE: The main objective of this study is the evaluation of RPPW anaerobic digestion feasibility at laboratory scale under Mesophilic condition. The experiment is conducted using a two-stage biofilm digester of 5 L capacity with mobile support material.<br><br>RESULTS: Anaerobic treatment of wastewater from recycled pulp and paper industry in Morocco was tested using a laboratory-scale anaerobic biofilm digester that operated under mesophilic conditions over a 70-day. Chemical oxygen demand (COD) efficiency, volatile and total solid (VS, TS) elimination of the substrate during the process were: 78%, 52% and 48% respectively. The system was stable throughout its operating cycle with an optimum pH (7.24), alkalinity (1750 mg CaCO3/L) and a volatile fatty acid value (760 mg/L). The experimental daily biogas production measured reaches a value of 5 L/day with a composition of 71% methane, 27.6% carbon dioxide, 0.2 oxygen and 7713 ppm of the H2S. The study results show that the anaerobic biofilm reactor is a suitable technique for recycled pulp and paper wastewater (RPPW) treatment. The reactor shows high performances in terms of process stability, removal efficiency (> 70%) and biogas production.<br><br>CONCLUSION: Anaerobic digestion is an efficient waste treatment technology that uses natural anaerobic decomposition to reduce the volume of waste while producing biogas. However, research is needed to strengthen microbial metabolism, biochemistry and the functioning of the rector to improve biogas production. The RPPW AD experiment with biofilm digester technology was stable throughout the operation period. The digester knows an overloaded in the last phase of the experiment which leads to an inhibition of biogas production.},
}
@article {pmid31599128,
year = {2019},
author = {Turner, ME and Huynh, K and Carney, OV and Gross, D and Carroll, RK and Ahn, SJ and Rice, KC},
title = {Genomic instability of TnSMU2 contributes to Streptococcus mutans biofilm development and competence in a cidB mutant.},
journal = {MicrobiologyOpen},
volume = {},
number = {},
pages = {e934},
doi = {10.1002/mbo3.934},
pmid = {31599128},
issn = {2045-8827},
support = {1161177//National Science Foundation/ ; DE025237/NH/NIH HHS/United States ; DE025237/DE/NIDCR NIH HHS/United States ; //University of Florida/ ; },
abstract = {Streptococcus mutans is a key pathogenic bacterium in the oral cavity and a primary contributor to dental caries. The S. mutans Cid/Lrg system likely contributes to tolerating stresses encountered in this environment as cid and/or lrg mutants exhibit altered oxidative stress sensitivity, genetic competence, and biofilm phenotypes. It was recently noted that the cidB mutant had two stable colony morphologies: a &quot;rough&quot; phenotype (similar to wild type) and a &quot;smooth&quot; phenotype. In our previously published work, the cidB rough mutant exhibited increased sensitivity to oxidative stress, and RNAseq identified widespread transcriptomic changes in central carbon metabolism and oxidative stress response genes. In this current report, we conducted Illumina-based genome resequencing of wild type, cidB rough, and cidB smooth mutants and compared their resistance to oxidative and acid stress, biofilm formation, and competence phenotypes. Both cidB mutants exhibited comparable aerobic growth inhibition on agar plates, during planktonic growth, and in the presence of 1 mM hydrogen peroxide. The cidB smooth mutant displayed a significant competence defect in BHI, which was rescuable by synthetic CSP. Both cidB mutants also displayed reduced XIP-mediated competence, although this reduction was more pronounced in the cidB smooth mutant. Anaerobic biofilms of the cidB smooth mutant displayed increased propidium iodide staining, but corresponding biofilm CFU data suggest this phenotype is due to cell damage and not increased cell death. The cidB rough anaerobic biofilms showed altered structure relative to wild type (reduced biomass and average thickness) which correlated with decreased CFU counts. Sequencing data revealed that the cidB smooth mutant has a unique &quot;loss of read coverage&quot; of ~78 kb of DNA, corresponding to the genomic island TnSMU2 and genes flanking its 3' end. It is therefore likely that the unique biofilm and competence phenotypes of the cidB smooth mutant are related to its genomic changes in this region.},
}
@article {pmid31594958,
year = {2019},
author = {Liu, W and Tian, XQ and Wei, JW and Ding, LL and Qian, W and Liu, Z and Wang, FF},
title = {Author Correction: BsmR degrades c-di-GMP to modulate biofilm formation of nosocomial pathogen Stenotrophomonas maltophilia.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {14778},
doi = {10.1038/s41598-019-43380-7},
pmid = {31594958},
issn = {2045-2322},
abstract = {A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.},
}
@article {pmid31593452,
year = {2019},
author = {Chen, H and Luo, J and Liu, S and Yuan, Z and Guo, J},
title = {Microbial Methane Conversion to Short-chain Fatty Acids Using Various Electron Acceptors in Membrane Biofilm Reactors.},
journal = {Environmental science &amp; technology},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.est.8b06767},
pmid = {31593452},
issn = {1520-5851},
abstract = {Given our vast methane reserves and the forecasted shortage of crude oil in the not too distant future, the conversion of methane into value-added liquid chemicals or fuels would be beneficial. The generated chemicals or fuels could augment the petroleum-dominated chemical market, and also satisfy the increasing demand for transportation fuels. While methane bioconversion to liquid chemicals has just been reported recently, there is limited understanding of the process. This study aims to clarify the potential electron acceptors that could support the process. Here we operated four membrane biofilm reactors (MBfRs) fed with nitrate, nitrite, oxygen at a relatively low rate and oxygen at a relatively high rate, respectively, to study if they can support methane bioconversion to short-chain fatty acids (SCFAs), and the associated microbiological features. All tested electron acceptors facilitated methane bioconversion to SCFAs (ranging from 1.1 to 36.7 mg acetate L-1 d-1, or 3.4 to 114.6 mg acetate d-1 m-2 of biofilm). The carbon efficiency was estimated to be 7.9 ± 1.4% to 148.5 ± 1.3%, with an efficiency higher than 100% suggesting the assimilation of other carbon, very likely CO2, into the products. A low oxygen supply rate of 46.4 ± 2.3 mg O2 d-1 m-2 was found to be the most favourable among all the electron conditions provided according to the SCFAs production rate and also the carbon utilization efficiency. Microbial characterization revealed that completely different communities evolved in the respective reactors, suggesting diverse microbial pathways exist for methane bioconversion into value-added chemicals.},
}
@article {pmid31590609,
year = {2019},
author = {Diaz, PI and Valm, AM},
title = {Microbial Interactions in Oral Communities Mediate Emergent Biofilm Properties.},
journal = {Journal of dental research},
volume = {},
number = {},
pages = {22034519880157},
doi = {10.1177/0022034519880157},
pmid = {31590609},
issn = {1544-0591},
abstract = {Oral microbial communities are extraordinarily complex in taxonomic composition and comprise interdependent biological systems. The bacteria, archaea, fungi, and viruses that thrive within these communities engage in extensive cell-cell interactions, which are both beneficial and antagonistic. Direct physical interactions among individual cells mediate large-scale architectural biofilm arrangements and provide spatial proximity for chemical communication and metabolic cooperation. In this review, we summarize recent work in identifying specific molecular components that mediate cell-cell interactions and describe metabolic interactions, such as cross-feeding and exchange of electron acceptors and small molecules, that modify the growth and virulence of individual species. We argue, however, that although pairwise interaction models have provided useful information, complex community-like systems are needed to study the properties of oral communities. The networks of multiple synergistic and antagonistic interactions within oral biofilms give rise to the emergent properties of persistence, stability, and long-range spatial structure, with these properties mediating the dysbiotic transitions from health to oral diseases. A better understanding of the fundamental properties of interspecies networks will lead to the development of effective strategies to manipulate oral communities.},
}
@article {pmid31584765,
year = {2019},
author = {García, A and Martínez, C and Juárez, RI and Téllez, R and Paredes, MA and Herrera, MDR and Giono, S},
title = {Methicillin resistance and biofilm production in clinical isolates of Staphylococcus aureus and coagulase-negative Staphylococcus in México.},
journal = {Biomedica : revista del Instituto Nacional de Salud},
volume = {39},
number = {3},
pages = {513-523},
doi = {10.7705/biomedica.4131},
pmid = {31584765},
issn = {0120-4157},
}
@article {pmid31589910,
year = {2019},
author = {Miryala, S and Makala, H and Yadavali, SP and Venkatasubramanian, U and Subbaiah, N and Srinandan, CS},
title = {Disperse red 15 (DR15) impedes biofilm formation of uropathogenic Escherichia coli.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {103772},
doi = {10.1016/j.micpath.2019.103772},
pmid = {31589910},
issn = {1096-1208},
abstract = {Catheter associated urinary tract infection (CAUTI) is a highly prevalent hospital-acquired infection that is predominantly caused by uropathogenic Escherichia coli (UPEC). It adheres on catheter surface using type I pili as the initial step of pathogenesis that progresses to form biofilm. In this study, potential inhibitors against FimH adhesin of type I pili were screened computationally that yielded ten compounds. These were further validated in vitro against adhesion and biofilm formation. The compounds, 1-Amino-4-hydroxyanthraquinone (Disperse Red 15 or DR15) and 4-(4'-chloro-4-biphenylylsulfonylamino) benzoic acid (CB1) impaired adhesion and biofilm formation without inhibiting the planktonic growth. Also, both compounds inhibited cell assemblages like autoaggregation and swarming motility by unknown mechanisms. DR15 was further derivatized into N-(4-hydroxy-9,10-dioxo-9,10-dihydroanthracen-1-yl) undec-10-enamide that self-assembled with linseed oil, which was used as the coating material on urinary Foley catheters. The thin-film coating on the catheter did not leach when incubated in artificial urine and effectively restricted biofilm formation of UPEC. Altogether, the thin-film coating of urinary catheter with DR15 inhibited biofilm formation of UPEC and this application could potentially help to reduce CAUTI incidents in healthcare facilities.},
}
@article {pmid31589311,
year = {2019},
author = {Silva, MOD and Pernthaler, J},
title = {Priming of microcystin degradation in carbon-amended membrane biofilm communities is promoted by oxygen limited conditions.},
journal = {FEMS microbiology ecology},
volume = {},
number = {},
pages = {},
doi = {10.1093/femsec/fiz157},
pmid = {31589311},
issn = {1574-6941},
abstract = {Microbial biofilms are an important element of gravity-driven membrane (GDM) filtration systems for decentralized drinking water production. Mature biofilms fed with biomass from the toxic cyanobacterium Microcystis aeruginosa efficiently remove the cyanotoxin microcystin (MC). MC degradation can be 'primed' by prior addition of biomass from a non-toxic M. aeruginosa strain. Increased proportions of bacteria with an anaerobic metabolism in M. aeruginosa-fed biofilms suggest that this 'priming' could be due to higher productivity and the resulting changes in habitat conditions. We, therefore, investigated GDM systems amended with the biomass of toxic [WT] or non-toxic [MUT] M. aeruginosa strains, of diatoms [DT], or with starch solution (ST). After 25 days, these treatments were changed to receiving toxic cyanobacterial biomass. MC degradation established significantly more rapidly in MUT and ST than in DT. Oxygen measurements suggested that this was due to oxygen limited conditions in MUT and ST already prevailing before addition of MC-containing biomass. Moreover, the microbial communities in the initial ST biofilms featured high proportions of facultative anaerobic taxa, whereas aerobes dominated in DT biofilms. Thus, the 'priming' of MC degradation in mature GDM biofilms seems to be related to the prior establishment of oxygen limited conditions mediated by higher productivity.},
}
@article {pmid31589240,
year = {2019},
author = {Favre, L and Ortalo-Magné, A and Kerloch, L and Pichereaux, C and Misson, B and Briand, JF and Garnier, C and Culioli, G},
title = {Metabolomic and proteomic changes induced by growth inhibitory concentrations of copper in the biofilm-forming marine bacterium Pseudoalteromonas lipolytica.},
journal = {Metallomics : integrated biometal science},
volume = {},
number = {},
pages = {},
doi = {10.1039/c9mt00184k},
pmid = {31589240},
issn = {1756-591X},
abstract = {Copper is an essential element for living cells but this metal is present in some marine environments at such high concentrations that it can be toxic for numerous organisms. In polluted areas, marine organisms may develop specific adaptive responses to prevent cell damage. To investigate the influence of copper on the metabolism of a single organism, a dual approach combining metabolomics and proteomics was undertaken on the biofilm-forming bacterial strain Pseudoalteromonas lipolytica TC8. In order to highlight differential adaptation according to the phenotype, the response of P. lipolytica TC8 to copper stress was studied in planktonic and biofilm culture modes under growth inhibitory copper concentrations. As expected, copper exposure led to the induction of defense and detoxification mechanisms. Specific metabolite and protein profiles were thus observed in each condition (planktonic vs. biofilm and control vs. copper-treated cultures). Copper exposure seems to induce drastic changes in the lipid composition of the bacterial cell membrane and to modulate the abundance of proteins functionally known to be involved in copper cell homeostasis in both planktonic and biofilm culture modes. Much more proteins differentially expressed after copper treatment were observed in biofilms than in planktonic cells, which could indicate a more heterogeneous response of biofilm cells to this metallic stress.},
}
@article {pmid31586764,
year = {2019},
author = {Liu, X and Zhuo, S and Jing, X and Yuan, Y and Rensing, C and Zhou, S},
title = {Flagella act as Geobacter biofilm scaffolds to stabilize biofilm and facilitate extracellular electron transfer.},
journal = {Biosensors &amp; bioelectronics},
volume = {146},
number = {},
pages = {111748},
doi = {10.1016/j.bios.2019.111748},
pmid = {31586764},
issn = {1873-4235},
abstract = {Flagella are widely expressed in electroactive biofilms; however, their actual role is unknown. To understand the role of flagella, two Geobacter sulfurreducens strains (KN400 and PCA, with and without flagella, respectively) were selected. We restored flagellum expression in trans in strain PCA and prevented flagellum expression in strain KN400. Electrochemical results showed that flagellum restoration in strain PCA promoted current generation, while flagellum deletion in strain KN400 impaired current production. However, the expression of conductive pili and outer surface c-type cytochromes was not affected. Further microscopic analyses demonstrated that flagella promoted the formation of thicker biofilms and served as biofilm matrix scaffolds to accommodate more extracellular cytochromes with an orderly arrangement, which increased the electron diffusion rate within the biofilm. Our findings reveal an unprecedented structural role for flagella in stabilizing electroactive biofilms and highlight the importance of cytochromes in electron transfer across biofilms, which will deepen our understanding of biofilm conductivity.},
}
@article {pmid31586475,
year = {2019},
author = {Shi, N and Gao, Y and Yin, D and Song, Y and Kang, J and Li, X and Zhang, Z and Feng, X and Duan, J},
title = {The effect of the sub-minimal inhibitory concentration and the concentrations within resistant mutation window of ciprofloxacin on MIC, swimming motility and biofilm formation of Pseudomonas aeruginosa.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {103765},
doi = {10.1016/j.micpath.2019.103765},
pmid = {31586475},
issn = {1096-1208},
abstract = {OBJECTIVE: To explore the effect of sub-minimal inhibitory concentration (sub-MIC) and concentrations within resistant mutation window (MSW) of ciprofloxacin (CIP) on minimal inhibitory concentration (MIC), swimming motility and biofilm formation of Pseudomonas aeruginosa, and also to investigate the correlation between swimming motility and genes expression of lasI, lasR, rhlI, rhlR and pqsR.<br><br>METHODS: The collected strains were incubated under four different concentrations for 5 days. The MIC and mutant prevention concentration (MPC) were measured by the agar dilution method. The diameter of turbid cycle was used to signify the swimming motility. The biofilm formation was measured by the crystal violet stain method. The genes expression of lasI, lasR, rhlI, rhlR and pqsR were measured by RT-PCR.<br><br>RESULTS: A total of 11 P. aeruginosa which sensitive to CIP were collected. The incubation within concentrations of MSW made MICs to CIP increased more obviously than under sub-MIC (P < 0.05). The swimming motility showed a trend of being inhibited first and then promoted over time under sub-MIC (P < 0.05), whereas, it was promoted under concentrations within MSW. The biofilm formation was significantly promoted under the concentration of 4×MIC (P < 0.05). Under sub-MIC, the genes expression of rhlR and pqsR had a middle level positive correlation with the promotion of the swimming motility (P < 0.05, r = 0.788 and P < 0.05, r = 0.652, respectively).<br><br>CONCLUSIONS: Under the concentration of sub-MIC (0.5×MIC) and the concentrations within MSW (1×MIC, 2×MIC and 4×MIC), the effect of CIP on MICs, swimming motility and biofilm formation of P.aeruginosa was quite different. The genes expression of rhlR and pqsR had a middle level positive correlation with the promotion of the swimming motility.},
}
@article {pmid31585061,
year = {2019},
author = {Thompson, AF and English, EL and Nock, AM and Willsey, GG and Eckstrom, K and Cairns, B and Bavelock, M and Tighe, SW and Foote, A and Shulman, H and Pericleous, A and Gupta, S and Kadouri, DE and Wargo, MJ},
title = {Characterizing species interactions that contribute to biofilm formation in a multispecies model of a potable water bacterial community.},
journal = {Microbiology (Reading, England)},
volume = {},
number = {},
pages = {},
doi = {10.1099/mic.0.000849},
pmid = {31585061},
issn = {1465-2080},
abstract = {Microbial biofilms are ubiquitous in drinking water systems, yet our understanding of drinking water biofilms lags behind our understanding of those in other environments. Here, a six-member model bacterial community was used to identify the interactions and individual contributions of each species to community biofilm formation. These bacteria were isolated from the International Space Station potable water system and include Cupriavidus metallidurans, Chryseobacterium gleum, Ralstonia insidiosa, Ralstonia pickettii, Methylorubrum (Methylobacterium) populi and Sphingomonas paucimobilis, but all six species are common members of terrestrial potable water systems. Using reconstituted assemblages, from pairs to all 6 members, community biofilm formation was observed to be robust to the absence of any single species and only removal of the C. gleum/S. paucimobilis pair, out of all 15 possible 2-species subtractions, led to loss of community biofilm formation. In conjunction with these findings, dual-species biofilm formation assays supported the view that the contribution of C. gleum to community biofilm formation was dependent on synergistic biofilm formation with either R. insidiosa or C. metallidurans. These data support a model of multiple, partially redundant species interactions to generate robustness in biofilm formation. A bacteriophage and multiple predatory bacteria were used to test the resilience of the community to the removal of individual members in situ, but the combination of precise and substantial depletion of a single target species was not achievable. We propose that this assemblage can be used as a tractable model to understand the molecular bases of the interactions described here and to decipher other functions of drinking water biofilms.},
}
@article {pmid31585041,
year = {2019},
author = {Xi, Y and Wang, Y and Gao, J and Xiao, Y and Du, J},
title = {Dual Corona Vesicles with Intrinsic Antibacterial and Enhanced Antibiotic Delivery Capabilities for Effective Treatment of Biofilm-Induced Periodontitis.},
journal = {ACS nano},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsnano.9b03237},
pmid = {31585041},
issn = {1936-086X},
abstract = {Periodontitis is a common disease caused by plaque biofilms, which are important pathogenic factors of many diseases and may be eradicated by antibiotic therapy. However, low dose antibiotic therapy is a complicated challenge for eradiating biofilms as hundreds (even thousands) of times higher concentrations of antibiotics are needed than killing planktonic bacteria. Polymer vesicles may solve these problems via effective antibiotic delivery into biofilms, but traditional single corona vesicles lack the multifunctionalities essential for biofilm eradication. In this paper, we aim to effectively treat biofilm-induced periodontitis using much lower concentrations of antibiotics than traditional antibiotic therapy by designing a multifunctional dual corona vesicle with intrinsic antibacterial and enhanced antibiotic delivery capabilities. This vesicle is co-assembled from two block copolymers, poly(ε-caprolactone)-block-poly(lysine-stat-phenylalanine) [PCL-b-P(Lys-stat-Phe)] and poly(ethylene oxide)-block-poly(ε-caprolactone) [PEO-b-PCL]. Both PEO and P(Lys-stat-Phe) coronas have their specific functions: PEO endows vesicles with protein repelling ability to penetrate extracellular polymeric substances (EPS) in biofilms ('stealthy' coronas), while P(Lys-stat-Phe) provides vesicles with positive charges and broad spectrum intrinsic antibacterial activity. As a result, the dosage of antibiotics can be reduced by 50% when encapsulated in the dual corona vesicles to eradicate Escherichia coli (E. coli) or Staphylococcus aureus (S. aureus) biofilms. Furthermore, effective in vivo treatment has been achieved from a rat periodontitis model, as confirmed by significantly reduced dental plaque, and alleviated inflammation. Overall, this 'stealthy' and antibacterial dual corona vesicle demonstrates a fresh insight for improving the antibiofilm efficiency of antibiotics and combating the serious threat of biofilm-associated diseases.},
}
@article {pmid31584713,
year = {2019},
author = {Soares Dos Santos, DM and Braga, AS and Rizk, M and Wiegand, A and Magalhães, AC},
title = {Comparison between micro-computed tomography and transverse microradiography of sound dentine treated with fluorides and demineralized by microcosm biofilm.},
journal = {European journal of oral sciences},
volume = {},
number = {},
pages = {},
doi = {10.1111/eos.12656},
pmid = {31584713},
issn = {1600-0722},
support = {MWK INST 1525/39-1 FUGG//Deutsche Forschungsgemeinschaft/ ; 2017/13386-5//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 2017/00556-0//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; },
abstract = {The study aimed to apply micro-computed tomography (micro-CT) and transverse microradiography (TMR) to measure dentine demineralization and to test the preventive effect of titanium tetrafluoride (TiF4) under microcosm biofilm. Sound dentine specimens from bovine root were treated for 6 h with: (i) 4.0% titanium tetrafluoride (TiF4) varnish [pH 1.0, 2.45% fluoride (F-); (ii) 5.42% sodium fluoride (NaF) varnish (pH 5.0, 2.45% F); (iii) 2% chlorhexidine (CHX) gel (pH 7.0); (iv) placebo varnish (pH 5.0); or (v) no agent (untreated). Dentine specimens were then exposed to human saliva mixed with McBain saliva for 8 h. Thereafter, McBain saliva containing 0.2% sucrose was applied daily, for 5 d, onto dentine specimens to stimulate formation of microcosm biofilm. Although a high correlation was found between the results of both methods regarding integrated mineral loss, the results of the methods did not show good agreement in Bland-Altman plots, with significant biases in calculations of lesion depth. Fluoride varnishes were able to reduce dentine demineralization (P < 0.05), while CHX failed to do so. Fluorides are still the best option to reduce dentine demineralization. Micro-CT may be used to measure dentine mineral loss, but not the lesion depth, for which TMR is superior.},
}
@article {pmid31584030,
year = {2019},
author = {Yadav, S and Sachdev, V and Malik, M and Chopra, R},
title = {Effect of three different compositions of topical fluoride varnishes with and without prior oral prophylaxis on Streptococcus mutans count in biofilm samples of children aged 2-8 years: A randomized controlled trial.},
journal = {Journal of the Indian Society of Pedodontics and Preventive Dentistry},
volume = {37},
number = {3},
pages = {286-291},
doi = {10.4103/JISPPD.JISPPD_62_19},
pmid = {31584030},
issn = {1998-3905},
abstract = {Background: Various strategies for controlling caries focus on disrupting the interaction between risk factors. Of these, fluoride varnish has been shown to reduce the colony-forming (CFU) units and water-insoluble extracellular polysaccharide amount. Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and xylitol-containing fluoride varnishes have recently gained importance as caries-protective fluoride varnishes.<br><br>Aim: This study aims to assess and compare the reduction in Streptococcus mutans count in biofilm samples after topical application of three different fluoride varnishes and to evaluate the effect of oral prophylaxis prior to fluoride varnish application.<br><br>Materials and Methods: Sixty healthy children with no active caries, in the age group of 2-8 years, were randomly divided into Group A = fluoride varnish containing CPP-ACP; Group B = fluoride varnish containing xylitol; and Group C = fluoride varnish with 0.9% difluorosilane; further, the groups were divided into two subgroups, namely A1, B1, and C1 with prior oral prophylaxis and A2, B2, and C2 without oral prophylaxis. Plaque samples were collected at baseline, 1st month, and 3rd month; cultured; and incubated, and CFU/ml was calculated.<br><br>Results: Data were compiled, and CFU/ml was analyzed by independent t-test, paired t-test, and one-way ANOVA. There was no statistical difference between the fluoride groups. Furthermore, no statistically significant difference was seen between the subgroups.<br><br>Conclusion: Fluoride varnish containing CPP-ACP showed higher reduction in S. mutans count followed by xylitol-containing fluoride varnish and Fluor Protector®. There was no effect of prior oral prophylaxis on the efficacy of fluoride varnish.},
}
@article {pmid31583791,
year = {2019},
author = {Dundas, AA and Sanni, O and Dubern, JF and Dimitrakis, G and Hook, AL and Irvine, DJ and Williams, P and Alexander, MR},
title = {Validating a Predictive Structure-Property Relationship by Discovery of Novel Polymers which Reduce Bacterial Biofilm Formation.},
journal = {Advanced materials (Deerfield Beach, Fla.)},
volume = {},
number = {},
pages = {e1903513},
doi = {10.1002/adma.201903513},
pmid = {31583791},
issn = {1521-4095},
support = {EP/N006615/1//Engineering and Physical Sciences Research Council/ ; 103882/WT_/Wellcome Trust/United Kingdom ; 103884/WT_/Wellcome Trust/United Kingdom ; //University of Nottingham/ ; },
abstract = {Synthetic materials are an everyday component of modern healthcare yet often fail routinely as a consequence of medical-device-centered infections. The incidence rate for catheter-associated urinary tract infections is between 3% and 7% for each day of use, which means that infection is inevitable when resident for sufficient time. The O'Neill Review on antimicrobial resistance estimates that, left unchecked, ten million people will die annually from drug-resistant infections by 2050. Development of biomaterials resistant to bacterial colonization can play an important role in reducing device-associated infections. However, rational design of new biomaterials is hindered by the lack of quantitative structure-activity relationships (QSARs). Here, the development of a predictive QSAR is reported for bacterial biofilm formation on a range of polymers, using calculated molecular descriptors of monomer units to discover and exemplify novel, biofilm-resistant (meth-)acrylate-based polymers. These predictions are validated successfully by the synthesis of new monomers which are polymerized to create coatings found to be resistant to biofilm formation by six different bacterial pathogens: Pseudomonas aeruginosa, Proteus mirabilis, Enterococcus faecalis, Klebsiella pneumoniae, Escherichia coli, and Staphylococcus aureus.},
}
@article {pmid31583108,
year = {2019},
author = {Guilhen, C and Miquel, S and Charbonnel, N and Joseph, L and Carrier, G and Forestier, C and Balestrino, D},
title = {Colonization and immune modulation properties of Klebsiella pneumoniae biofilm-dispersed cells.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {25},
doi = {10.1038/s41522-019-0098-1},
pmid = {31583108},
issn = {2055-5008},
abstract = {Biofilm-dispersal is a key determinant for further dissemination of biofilm-embedded bacteria. Recent evidence indicates that biofilm-dispersed bacteria have transcriptional features different from those of both biofilm and planktonic bacteria. In this study, the in vitro and in vivo phenotypic properties of Klebsiella pneumoniae cells spontaneously dispersed from biofilm were compared with those of planktonic and sessile cells. Biofilm-dispersed cells, whose growth rate was the same as that of exponential planktonic bacteria but significantly higher than those of sessile and stationary planktonic forms, colonized both abiotic and biotic surfaces more efficiently than their planktonic counterparts regardless of their initial adhesion capabilities. Microscopy studies suggested that dispersed bacteria initiate formation of microcolonies more rapidly than planktonic bacteria. In addition, dispersed cells have both a higher engulfment rate and better survival/multiplication inside macrophages than planktonic cells and sessile cells. In an in vivo murine pneumonia model, the bacterial load in mice lungs infected with biofilm-dispersed bacteria was similar at 6, 24 and 48 h after infection to that of mice lungs infected with planktonic or sessile bacteria. However, biofilm-dispersed and sessile bacteria trend to elicit innate immune response in lungs to a lesser extent than planktonic bacteria. Collectively, the findings from this study suggest that the greater ability of K. pneumoniae biofilm-dispersed cells to efficiently achieve surface colonization and to subvert the host immune response confers them substantial advantages in the first steps of the infection process over planktonic bacteria.},
}
@article {pmid31581038,
year = {2019},
author = {Henning, N and Falås, P and Castronovo, S and Jewell, KS and Bester, K and Ternes, TA and Wick, A},
title = {Biological transformation of fexofenadine and sitagliptin by carrier-attached biomass and suspended sludge from a hybrid moving bed biofilm reactor.},
journal = {Water research},
volume = {167},
number = {},
pages = {115034},
doi = {10.1016/j.watres.2019.115034},
pmid = {31581038},
issn = {1879-2448},
abstract = {Laboratory-scale experiments were conducted to investigate the (bio)transformation of the antidiabetic sitagliptin (STG) and the antihistamine fexofenadine (FXF) during wastewater treatment. As inoculum either attached-growth on carriers or suspended sludge from a hybrid moving bed biofilm reactor (HMBBR) was used. Both target compounds were incubated in degradation experiments and quantified via LC-MS/MS for degradation kinetics. Furthermore transformation products (TPs) were analyzed via high resolution mass spectrometry (HRMS). Structural elucidation of the TPs was based on the high resolution molecular ion mass to propose a molecular formula and on MS2 fragmentation to elucidate the chemical structure of the TPs. In total, 22 TPs (9 TPs for STG and 13 TPs for FXF) were detected in the experiments with STG and FXF. For all TPs, chemical structures could be proposed. STG was mainly transformed via amide hydrolysis and conjugation of the primary amine moiety. In contrast, FXF was predominantly transformed by oxidative reactions such as oxidation (dehydrogenation) and hydroxylation. Furthermore, FXF was removed significantly faster in contact with carriers compared to suspended sludge, whereas STG was degraded slightly faster in contact with suspended sludge. Moreover, the primary TP of FXF was also degraded faster in contact with carriers leading to higher proportions of secondary TPs. Thus, the microbial community of both carriers and suspended sludge catalyzed the same primary transformation reactions but the transformation kinetics of FXF and the formation/degradation of FXF TPs were considerably higher in contact with carrier-attached biomass. The primary degradation of both target compounds in pilot- and full-scale conventional activated sludge (CAS) and MBBR reactors reached 42 and 61% for FXF and STG, respectively. Up to three of the identified TPs of FXF and 8 TPs of STG were detected in the effluents of pilot- and full-scale CAS and MBBR.},
}
@article {pmid31580958,
year = {2019},
author = {Arteaga, V and Lamas, A and Regal, P and Vázquez, B and Miranda, JM and Cepeda, A and Franco, CM},
title = {Antimicrobial activity of apitoxin from Apis mellifera in Salmonella enterica strains isolated from poultry and its effects on motility, biofilm formation and gene expression.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {103771},
doi = {10.1016/j.micpath.2019.103771},
pmid = {31580958},
issn = {1096-1208},
abstract = {Salmonella is a major global food-borne pathogen. One of the main concerns related to Salmonella and other food-borne pathogens is their capacity to acquire antimicrobial resistance and produce biofilms. Due to the increased resistance to common antimicrobials used to treat livestock animals and human infections, the discovery of new antimicrobial substances is one of the main challenges in microbiological research. An additional challenge is the development of new methods and substances to inhibit and destruct biofilms. We determined the antimicrobial and antibiofilm activities of apitoxin in 16 Salmonella strains isolated from poultry. In addition, the effect of apitoxin on Salmonella motility and the expression of biofilm- and virulence-related genes was evaluated. The minimum inhibitory concentrations (MIC) of apitoxin ranged from 1,024-256 μg/mL, with 512 μg/mL being the most common. Sub-inhibitory concentrations of apitoxin significantly reduced biofilm formation in 14 of the 16 Salmonella strains tested, with significant increases in motility. MIC concentrations of apitoxin destroyed the pre-formed biofilm by 27.66-68.22% (47.00% ± 10.91). The expression of biofilm- and virulence-related genes and small RNAs was differentially regulated according to the strain and the presence of apitoxin. The transcription of the small RNAs dsrA and csrB, related to antimicrobial resistance, was upregulated in the presence of apitoxin. We suggest that apitoxin is a potential antimicrobial substance that could be used in combination with other substances to develop new drugs and sanitizers against food-borne pathogens.},
}
@article {pmid31579334,
year = {2019},
author = {Kamiya, M and Mori, T and Nomura, M and Inagaki, T and Nonogaki, T and Nagatsu, A and Yamagishi, Y and Mikamo, H and Ikeda, Y},
title = {Tradescantia pallida extract inhibits biofilm formation in Pseudomonas aeruginosa.},
journal = {Nagoya journal of medical science},
volume = {81},
number = {3},
pages = {439-452},
doi = {10.18999/nagjms.81.3.439},
pmid = {31579334},
issn = {2186-3326},
abstract = {Pseudomonas aeruginosa is capable of biofilm formation. In this study, we investigated the effects of aqueous Tradescantia pallida extract on Pseudomonas aeruginosa growth and biofilm formation. Aqueous Tradescantia pallida extracts significantly inhibited both bacterial growth and biofilm formation. However, methanolic Tradescantia pallida extracts inhibited neither. Aqueous Tradescantia pallida extracts were deactivated by heating but were not deactivated by light exposure. The ingredients retained the inhibitory effect on the bacterial growth and biofilm formation after ultrafiltration of aqueous Tradescantia pallida extract. Furthermore, polyphenol-rich Tradescantia pallida extracts inhibited bacterial growth, thus, polyphenols are possible to be an active ingredient. We observed the biofilm by scanning electron microscopy, and quantitative and qualitative differences in the biofilm and cells morphology. Interestingly, the biofilm treated aqueous Tradescantia pallida extracts remained premature. We postulated that premature biofilm formation was due to the inhibition of swarming motility. Indeed, aqueous Tradescantia pallida extracts inhibited swarming motility. These results demonstrate that Peudomonas aeruginosa growth and biofilm formation are inhibited by aqueous Tradescantia pallida extracts.},
}
@article {pmid31578154,
year = {2019},
author = {Shi, YJ and Fang, QJ and Huang, HQ and Gong, CG and Hu, YH},
title = {HutZ is required for biofilm formation and contributes to the pathogenicity of Edwardsiella piscicida.},
journal = {Veterinary research},
volume = {50},
number = {1},
pages = {76},
doi = {10.1186/s13567-019-0693-4},
pmid = {31578154},
issn = {1297-9716},
support = {41476138//National Natural Science Foundation of China/ ; },
abstract = {Edwardsiella piscicida is a severe fish pathogen. Haem utilization systems play an important role in bacterial adversity adaptation and pathogenicity. In this study, a speculative haem utilization protein, HutZEp, was characterized in E. piscicida. hutZEp is encoded with two other genes, hutW and hutX, in an operon that is similar to the haem utilization operon hutWXZ identified in V. cholerae. However, protein activity analysis showed that HutZEp is probably not related to hemin utilization. To explore the biological role of HutZEp, a markerless hutZEp in-frame mutant strain, TX01ΔhutZ, was constructed. Deletion of hutZEp did not significantly affect bacterial growth in normal medium, in iron-deficient conditions, or in the presence of haem but significantly retarded bacterial biofilm growth. The expression of known genes related to biofilm growth was not affected by hutZEp deletion, which indicated that HutZEp was probably a novel factor promoting biofilm formation in E. piscicida. Compared to the wild-type TX01, TX01ΔhutZ exhibited markedly compromised tolerance to acid stress and host serum stress. Pathogenicity analysis showed that inactivation of hutZEp significantly impaired the ability of E. piscicida to invade and reproduce in host cells and to infect host tissue. In contrast to TX01, TX01ΔhutZ was defective in blocking host macrophage activation. The expression of hutZEp was directly regulated by the ferric uptake regulator Fur. This study is the first functional characterization of HutZ in a fish pathogen, and these findings suggested that HutZEp is essential for E. piscicida biofilm formation and contributes to host infection.},
}
@article {pmid31575315,
year = {2019},
author = {Namgoong, S and Jung, SY and Han, SK and Kim, AR and Dhong, ES},
title = {Clinical experience with surgical debridement and simultaneous meshed skin grafts in treating biofilm-associated infection: an exploratory retrospective pilot study.},
journal = {Journal of plastic surgery and hand surgery},
volume = {},
number = {},
pages = {1-8},
doi = {10.1080/2000656X.2019.1673170},
pmid = {31575315},
issn = {2000-6764},
abstract = {Current treatment guidelines for biofilm-associated infections (BAI) recommend repeated sharp/surgical debridement followed by treatment with antimicrobial agents until the wound becomes self-sustaining in terms of a positive wound-healing trajectory. However, complete removal of a biofilm is unlikely, and biofilms reform rapidly. We have treated BAI in patients with chronic diabetic ulcers using a meshed skin graft combined with negative pressure wound therapy (NPWT) immediately after surgical debridement, rather than waiting until the development of clean and healthy granulation tissue; the purpose of this exploratory study was to report the clinical results of this treatment strategy. This retrospective study included 75 patients with chronic diabetic ulcers who were treated for BAI by using surgical debridement, simultaneous meshed skin grafts, and NPWT. Healing time along with the percentage of complete wound closure within 12 weeks were evaluated; bacteria isolated from the wounds and their relation to the wound healing rate were investigated. All 75 wounds healed successfully, and the mean time for complete wound healing was 3.5 ± 1.8 weeks. In particular, 76% of wounds healed uneventfully without graft loss. A mean of 3.3 bacterial colonies/wound were isolated; however, no significant difference in wound healing was observed between the monomicrobial and polymicrobial groups. This exploratory study suggests that surgical debridement and simultaneous meshed skin grafts combined with NPWT may be successfully used to combat BAI in patients with chronic diabetic ulcers. We look forward to larger pivotal studies to confirm or refute these initially promising findings.},
}
@article {pmid31574542,
year = {2019},
author = {Meyer, F and Enax, J},
title = {Hydroxyapatite in Oral Biofilm Management.},
journal = {European journal of dentistry},
volume = {13},
number = {2},
pages = {287-290},
doi = {10.1055/s-0039-1695657},
pmid = {31574542},
issn = {1305-7456},
abstract = {Particulate hydroxyapatite, Ca5 (PO4)3 (OH), shows a good biocompatibility and is used as a biomimetic ingredient in dental care formulations due to its similarity to human enamel. Numerous studies show its efficiency, for example, in reducing dentin hypersensitivity, and in the remineralization of enamel and dentin. In addition, oral care products with hydroxyapatite improve periodontal health under in vivo conditions. This review article summarizes data on the effects of hydroxyapatite particles in oral biofilm management. Two databases (PubMed and SciFinder) were searched for studies using specific search terms. In contrast to frequently used antibacterial agents for biofilm control, such as chlorhexidine, stannous salts, and quaternary ammonium salts, hydroxyapatite particles in oral care products lead to a reduction in bacterial attachment to enamel surfaces in situ without having pronounced antibacterial effects or showing unwanted side effects such as tooth discoloration. Furthermore, antibacterial agents might lead to dysbiosis of the oral ecology, which was recently discussed regarding pros and cons. Remarkably, the antiadherent properties of hydroxyapatite particles are comparable to those of the gold standard in the field of oral care biofilm management, chlorhexidine in situ. Although biomimetic strategies have been less well analyzed compared with commonly used antibacterial agents in oral biofilm control, hydroxyapatite particles are a promising biomimetic alternative or supplement for oral biofilm management.},
}
@article {pmid31574321,
year = {2019},
author = {Fugolin, AP and Dobson, A and Huynh, V and Mbiya, W and Navarro, O and Franca, CM and Logan, M and Merritt, JL and Ferracane, JL and Pfeifer, CS},
title = {Antibacterial, Ester-Free Monomers: Polymerization Kinetics, Mechanical Properties, Biocompatibility and Anti-Biofilm Activity.},
journal = {Acta biomaterialia},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.actbio.2019.09.039},
pmid = {31574321},
issn = {1878-7568},
abstract = {OBJECTIVES: Quaternary ammonium (QA) methacrylate monomers have been extensively investigated and demonstrate excellent antibacterial properties. However, the presence of ester bonds makes them prone to degradation in the oral cavity. In this study, ester-free QA monomers based on meth-acrylamides were synthesized and screened for polymerization kinetics, mechanical properties and antibacterial effects.<br><br>MATERIALS AND METHODS: Tertiary quaternary ammonium acrylamides (AM) and methacrylamides (MAM) with alkyl side chain lengths of 9 and 14 carbons (C9 and C14) were synthesized and incorporated at 10 wt% into experimental composites based on BisGMA:TEGDMA (1:1), camphorquinone/ethyl-4-dimethylaminobenzoate (0.2/0.8 wt%) and 70 wt% barium glass fillers. Analogous methacrylate versions (MA) were used as controls. Degree of conversion (DC) and rate of polymerization (RP) during photoactivation (800 mW/cm2) were followed in real-time with near-IR. Flexural Strength (FS) and Modulus (E) were measured on 2 × 2 × 25 mm bars in 3-point bending after 24h dry storage and 7-day storage in water at 37°C. Antimicrobial properties and biofilm adhesion (fouling) were evaluated by bioluminescence (Luciferase Assay) and biofilm removal by water spray microjet impingement test, respectively. Cytotoxicity was assessed by MTT assay on dental pulp stem cells (DPSC). Data were analyzed with one-way ANOVA/Tukey's test (α=0.05).<br><br>RESULTS: DC was similar for all groups tested (∼70%). Both MAMs and C14-AM presented significantly lower RP. Under dry conditions, FS (110-120 MPa) and E (8-9 GPa) were similar for all groups. After water storage, all materials presented FS/E similar to the control, except for C14-AM (for FS) and C14-MAM (for E), which were lower. All C14 versions were strongly antibacterial, decreasing the titer counts of biofilm by more than two orders of magnitude in comparison to the control. C9 monomers did not present significant antibacterial nor antifouling properties. And biofilms had approximately equivalent adhesion on the C9 composites as on the control. Cytotoxicity did not show significant differences between the MA and AM versions and the control group.<br><br>CONCLUSIONS: C14-QA monomers based on methacrylates and meth-acrylamides present strong antibacterial properties, and in general, similar conversion/mechanical properties compared to the methacrylate control.},
}
@article {pmid31573125,
year = {2019},
author = {Romeu, MJ and Alves, P and Morais, J and Miranda, JM and de Jong, ED and Sjollema, J and Ramos, V and Vasconcelos, V and Mergulhão, FJ},
title = {Biofilm formation behaviour of marine filamentous cyanobacterial strains in controlled hydrodynamic conditions.},
journal = {Environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1462-2920.14807},
pmid = {31573125},
issn = {1462-2920},
abstract = {Marine biofouling has severe economic impacts and cyanobacteria play a significant role as early surface colonizers. Despite this fact, cyanobacterial biofilm formation studies in controlled hydrodynamic conditions are scarce. In this work, computational fluid dynamics was used to determine the shear rate field on coupons that were placed inside the wells of agitated 12-well microtiter plates. Biofilm formation by three different cyanobacterial strains was assessed at two different shear rates (4 and 40 s-1) which can be found in natural ecosystems and using different surfaces (glass and perspex). Biofilm formation was higher under low shear conditions and differences obtained between surfaces were not always statistically significant. The hydrodynamic effect was more noticeable during the biofilm maturation phase rather than during initial cell adhesion and Optical Coherence Tomography showed that different shear rates can affect biofilm architecture. This study is particularly relevant given the cosmopolitan distribution of these cyanobacterial strains and the biofouling potential of these organisms. This article is protected by copyright. All rights reserved.},
}
@article {pmid31570700,
year = {2019},
author = {Jiao, Y and Tay, FR and Niu, LN and Chen, JH},
title = {Advancing antimicrobial strategies for managing oral biofilm infections.},
journal = {International journal of oral science},
volume = {11},
number = {3},
pages = {28},
doi = {10.1038/s41368-019-0062-1},
pmid = {31570700},
issn = {2049-3169},
abstract = {Effective control of oral biofilm infectious diseases represents a major global challenge. Microorganisms in biofilms exhibit increased drug tolerance compared with planktonic cells. The present review covers innovative antimicrobial strategies for controlling oral biofilm-related infections published predominantly over the past 5 years. Antimicrobial dental materials based on antimicrobial agent release, contact-killing and multi-functional strategies have been designed and synthesized for the prevention of initial bacterial attachment and subsequent biofilm formation on the tooth and material surface. Among the therapeutic approaches for managing biofilms in clinical practice, antimicrobial photodynamic therapy has emerged as an alternative to antimicrobial regimes and mechanical removal of biofilms, and cold atmospheric plasma shows significant advantages over conventional antimicrobial approaches. Nevertheless, more preclinical studies and appropriately designed and well-structured multi-center clinical trials are critically needed to obtain reliable comparative data. The acquired information will be helpful in identifying the most effective antibacterial solutions and the most optimal circumstances to utilize these strategies.},
}
@article {pmid31570396,
year = {2019},
author = {Lopes, AA and Yoshii, Y and Yamada, S and Nagakura, M and Kinjo, Y and Mizunoe, Y and Okuda, KI},
title = {Roles of lytic transglycosylases in biofilm formation and β-lactam resistance in methicillin-resistant Staphylococcus aureus.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.01277-19},
pmid = {31570396},
issn = {1098-6596},
abstract = {Staphylococcus aureus is responsible for numerous community outbreaks and is one of the most frequent causes of nosocomial infections with significant morbidity and mortality. While the function of lytic transglycosylases (LTs) in relation to cell division, biofilm formation, and antibiotic resistance has been determined for several bacteria, their role in S. aureus remains largely unknown. The only known LTs in S. aureus are immunodominant staphylococcal antigen A (IsaA) and Staphylococcus epidermidis D protein (SceD). Our study demonstrates that, in a strain of methicillin-resistant S. aureus (MRSA), IsaA and SceD contribute differently to biofilm formation and β-lactam resistance. Deletion of isaA, but not sceD, led to decreased biofilm formation. Additionally, in isaA-deleted strains, β-lactam resistance was significantly decreased compared to that of wild-type strains. Plasmid-based expression of mecA, a major determinant of β-lactam resistance in MRSA, in an isaA-deleted strain did not restore β-lactam resistance, demonstrating that the β-lactam susceptibility phenotype is exhibited by isaA mutant regardless of the production level of PBP2a. Overall, our results suggest that IsaA is a potential therapeutic target for MRSA infections.},
}
@article {pmid31565797,
year = {2019},
author = {Wang, X and Kong, Y and Zhao, H and Yan, X},
title = {Dependence of the Bacillus subtilis biofilm expansion rate on phenotypes and the morphology under different growing conditions.},
journal = {Development, growth &amp; differentiation},
volume = {},
number = {},
pages = {},
doi = {10.1111/dgd.12627},
pmid = {31565797},
issn = {1440-169X},
support = {//Harvard University/ ; 11772047//The National Natural Science Foundation of China/ ; 11620101001//The National Natural Science Foundation of China/ ; 2017YFB1002701//National Key R&amp;D Program of China/ ; },
abstract = {Biofilms are communities of tightly associated bacteria encased in an extracellular matrix and attached to surfaces of various objects, such as liquid or solid surfaces. Here we use the multi-channel wide field stereo fluorescence microscope to characterize growth of the Bacillus subtilis biofilm, in which the bacterial strain was triple fluorescence labeled for three main phenotypes: motile, matrix producing and sporulating cells. We used the feature point matching approach analyzing time lapse experimental movies to study the biofilm expansion rate. We found that the matrix producing cells dominate the biofilm expansion, at the biofilm edge, the expansion rate of matrix producing cells was almost the same as the velocity of the whole biofilm; however, the motile and sporulating cells were nearly rest. We also found that the biofilm expansion rate evolution relates to cell differentiation and biofilm morphology, and other micro-environments can influence the biofilm growth, such as nutrient, substrate hardness and colony competition. From our work, we get a deeper understanding of the biofilm growth, which can help us to control and to further disperse the biofilm.},
}
@article {pmid31563809,
year = {2019},
author = {Han, C and Goodwine, J and Romero, N and Steck, KS and Sauer, K and Doiron, A},
title = {Enzyme-encapsulating polymeric nanoparticles: A potential adjunctive therapy in Pseudomonas aeruginosa biofilm-associated infection treatment.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {184},
number = {},
pages = {110512},
doi = {10.1016/j.colsurfb.2019.110512},
pmid = {31563809},
issn = {1873-4367},
abstract = {Pseudomonas aeruginosa is a pathogen known to be associated with a variety of diseases and conditions such as cystic fibrosis, chronic wound infections, and burn wound infections. A novel approach was developed to combat the problem of biofilm antibiotic tolerance by reverting biofilm bacteria back to the planktonic mode of growth. This reversion was achieved through the enzymatic depletion of available pyruvate using pyruvate dehydrogenase, which induced biofilm bacteria to disperse from the surface-associated mode of growth into the surrounding environment. However, direct use of the enzyme in clinical settings is not practical as the enzyme is susceptible to denaturation under various storage conditions. We hypothesize that by encapsulating pyruvate dehydrogenase into degradable, biocompatible poly(lactic-co-glycolic) acid nanoparticles, the activity of the enzyme can be extended to deplete available pyruvate and induce dispersion of mature Pseudomonas aeruginosa biofilms. Several particle formulations were attempted in order to permit the use of the smallest dose of nanoparticles while maintaining pyruvate dehydrogenase activity for an extended time length. The nanoparticles synthesized using the optimal formulation showed an average size of 266.7 ± 1.8 nm. The encapsulation efficiency of pyruvate dehydrogenase was measured at 17.9 ± 1.4%. Most importantly, the optimal formulation dispersed biofilms and exhibited enzymatic activity after being stored at 37 °C for 6 days.},
}
@article {pmid31563763,
year = {2019},
author = {Kart, D and Yabanoglu Ciftci, S and Nemutlu, E},
title = {Altered metabolomic profile of dual-species biofilm: Interactions between Proteus mirabilis and Candida albicans.},
journal = {Microbiological research},
volume = {230},
number = {},
pages = {126346},
doi = {10.1016/j.micres.2019.126346},
pmid = {31563763},
issn = {1618-0623},
abstract = {In this study, we aimed to determine the interspecies interactions between Proteus mirabilis and Candida albicans. Mono and dual-species biofilms were grown in a microtiter plate and metabolomic analysis of the biofilms was performed. The effects of togetherness of two species on the expression levels of candidal virulence genes and urease and swarming activities of P.mirabilis were investigated. The growth of C.albicans was inhibited by P.mirabilis whereas the growth and swarming activity of P.mirabilis were increased by C.albicans. The inhibition of Candida cell growth was found to be biofilm specific. The alteration was not detected in urease activity. The expressions of EFG1, HWP1 and SAP2 genes were significantly down-regulated, however, LIP1 was upregulated by P.mirabilis. In the presence of P.mirabilis carbonhydrates, amino acids, polyamine and lipid metabolisms were altered in C.albicans. Interestingly, the putrescine level was increased up to 230 fold in dual-species biofilm compared to monospecies C.albicans biofilm. To our knowledge, this is the first study to investigate the impact of each microbial pathogen on the dual microbial environment by integration of metabolomic data.},
}
@article {pmid31562986,
year = {2019},
author = {Caizán-Juanarena, L and Krug, JR and Vergeldt, FJ and Kleijn, JM and Velders, AH and Van As, H and Ter Heijne, A},
title = {3D biofilm visualization and quantification on granular bioanodes with magnetic resonance imaging.},
journal = {Water research},
volume = {167},
number = {},
pages = {115059},
doi = {10.1016/j.watres.2019.115059},
pmid = {31562986},
issn = {1879-2448},
abstract = {The use of microbial fuel cells (MFCs) for wastewater treatment fits in a circular economy context, as they can produce electricity by the removal of organic matter in the wastewater. Activated carbon (AC) granules are an attractive electrode material for bioanodes in MFCs, as they are cheap and provide electroactive bacteria with a large surface area for attachment. The characterization of biofilm growth on AC granules, however, is challenging due to their high roughness and three-dimensional structure. In this research, we show that 3D magnetic resonance imaging (MRI) can be used to visualize biofilm distribution and determine its volume on irregular-shaped single AC granules in a non-destructive way, while being combined with electrochemical and biomass analyses. Ten AC granules with electroactive biofilm (i.e. granular bioanodes) were collected at different growth stages (3 to 21 days after microbial inoculation) from a multi-anode MFC and T1-weighted 3D-MRI experiments were performed for three-dimensional biofilm visualization. With time, a more homogeneous biofilm distribution and an increased biofilm thickness could be observed in the 3D-MRI images. Biofilm volumes varied from 0.4 μL (day 4) to 2 μL (day 21) and were linearly correlated (R2 = 0.9) to the total produced electric charge and total nitrogen content of the granular bioanodes, with values of 66.4 C μL-1 and 17 μg N μL-1, respectively. In future, in situ MRI measurements could be used to monitor biofilm growth and distribution on AC granules.},
}
@article {pmid31561688,
year = {2019},
author = {Jain, AK and Misra, V and Ranjan, N and Jain, SB and Gandhi, S},
title = {Speciation, Biofilm Formation and Antifungal Susceptibility of Candida Isolates from Clinically Diagnosed Patient of UTI in a Tertiary Care Hospital.},
journal = {The Journal of the Association of Physicians of India},
volume = {67},
number = {9},
pages = {42-45},
pmid = {31561688},
issn = {0004-5772},
abstract = {Introduction: The incidence of the urinary tract infections caused by Candida species, are becoming more common. Recently, an increase in the incidence of infection caused by fungi especially non albicans candida species (NAC) has been reported. Several virulence factors like biofilm formation, toxin production and presence of adhesins contribute to its pathogenesis.<br><br>Objectives: This study was undertaken to determine species distribution, biofilm formation and in-vitro antifungal susceptibility of candida isolated in our tertiary care hospital.<br><br>Method: Eighty seven clinical isolates obtained from urine specimens were subjected to wet mount, Gram's stain and cultured on Sabouraud's Dextrose agar (SDA) medium. Conventional method for yeast identification was done. Biofilm forming ability of each isolate was detected using microtitre plate method. Antifungal susceptibility against posaconazole, amphotericin-B, fluconazole, itraconazole, ketoconazole, 5-flucytosine, voriconazole, and caspofungin was tested using Sensititre® Yeastone® (Trek diagnostic systems).<br><br>Results and Discussion: Out of 87 candida isolates, 31.03% (n=27) were C. albicans and 68.97% (n=60) were non albicans candida species (NAC). Among 60 NAC, C. kruseii 29.89% (n=26), C. glabrata 24.14% (n=21), C. tropicalis 14.94% (n=13). Among all isolates, 36.78% (n=32) were biofilm producers and biofilm positivity more among C. albicans 55.56% (n=15) as compared to NAC 28.33% (n=17) (Pvalue<0.002). The maximum positivity was observed with isolates from plastic devices (61.8%). The minimum inhibitory concentrations of all antifungal drugs against all isolates were within susceptible range except for fluconazole which was resistant to C. kruseii.<br><br>Conclusion: C. albicans remains the major isolate from urine samples and also biofilm formation as a virulence factor might have a higher significance for C. albicans than for NAC and its ability to form biofilm is intricately linked with ability of organisms to adhere, colonize and subsequently cause infection.},
}
@article {pmid31561306,
year = {2019},
author = {Yu, Z and Li, W and Tan, S},
title = {Real-time monitoring of the membrane biofouling based on spectroscopic analysis in a marine MBBR-MBR (moving bed biofilm reactor-membrane bioreactor) for saline wastewater treatment.},
journal = {Chemosphere},
volume = {235},
number = {},
pages = {1154-1161},
doi = {10.1016/j.chemosphere.2019.07.005},
pmid = {31561306},
issn = {1879-1298},
abstract = {A MBBR-MBR system has been developed with marine microorganisms enriched for saline wastewater treatment in this work, showing high COD and NH3-N removals. The behaviour of fouling-related components (EPS and SMP) has been studied as functions of operating time (40-90 days), salinity (0-30 g/L NaCl) and backflow ratio (0-300%, from MBR to MBBR). High biodegradability of the MBBR-MBR at optimal conditions can induce more biodegradation of humic acid-like (λex/λem: 350nm/430 nm) and fulvic acid-like (260nm/445 nm) molecules to soluble microbial by-product-like molecules (275nm/325 nm), reducing the membrane biofouling rate. The biodegradation process is suggested by the excitation-emission matrix (EEM) images. In the study of sudden salinity shock, results show that real-time monitoring the concentration of biofoulants is more effective (operative time extended by 60%) than monitoring the transmembrane pressure (operative time extended by 33%) to prevent membrane fouling. Due to an early warning from the real-time monitoring, the coming membrane-fouling is predictable and the operating conditions, such as backflow ratio, can be changed to minimize the biofouling rate.},
}
@article {pmid31558046,
year = {2019},
author = {Oliveira, GS and Lopes, DRG and Andre, C and Silva, CC and Baglinière, F and Vanetti, MCD},
title = {Multispecies biofilm formation by the contaminating microbiota in raw milk.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-13},
doi = {10.1080/08927014.2019.1666267},
pmid = {31558046},
issn = {1029-2454},
abstract = {Biofilms can be formed on the surfaces of dairy processing equipment and are a potential source of product contamination. This study evaluated the diversity of multispecies biofilms formed on stainless steel (SS) due to the contaminating microbiota in raw milk. Samples of raw milk were used: one was fresh milk and the other maintained in refrigerated bulk tanks for up to 48 h. The mesophilic aerobic contamination was ∼104 CFU ml-1 in fresh milk and 106 CFU ml-1 in bulk milk. SS coupons were kept immersed in the milk at 7 ±2 °C for 10 days, and every two days, the raw milk was changed for samples of the same origin collected on the current day. After incubation for 10 days, sessile cells in the biofilm reached 105 CFU cm-2 in the presence of fresh milk, and 106 CFU cm-2 in the presence of bulk milk. The genetic diversity analysis showed that Gammaproteobacteria and Bacilli predominated in the biofilms throughout the incubation of both milk samples and these biofilms showed a reduction in diversity over time. The main classes of bacteria found in these biofilms have representatives of great importance since many of them have spoilage potential.},
}
@article {pmid31557551,
year = {2019},
author = {Kurt, A and Cilingir, A and Bilmenoglu, C and Topcuoglu, N and Kulekci, G},
title = {Effect of different polishing techniques for composite resin materials on surface properties and bacterial biofilm formation.},
journal = {Journal of dentistry},
volume = {},
number = {},
pages = {103199},
doi = {10.1016/j.jdent.2019.103199},
pmid = {31557551},
issn = {1879-176X},
abstract = {OBJECTIVES: Both direct and indirect techniques are used for composite resin material (CRM) restorations. Polishing processes are needed in both techniques after intraoral adjustment. However, it is unclear as to which polishing technique should be preferred with respect to decreasing biofilm. The purpose of thisin vitro study was to evaluate the surface properties and Streptococcus mutans biofilm formation on direct and indirect CRMs after using different polishing techniques.<br><br>METHODS: Two CRMs (direct and indirect) and four polishing techniques (aluminium oxide discs, diamond polishing paste, aluminium oxide polishing paste, and silicon carbide brush) were evaluated. The specimens were prepared for taking scanning electron microscopy images (n = 2) and determining surface roughness, surface free energy, and bacterial biofilm formation (BBF) with colony-forming unit counting and confocal laser scanning microscopy assays (n = 7). The data were analysed using two-way analysis of variance with Bonferroni as a post hoc test and Pearson's correlation (p < .05).<br><br>RESULTS: The surface roughness values in the control group were higher than those in the diamond polishing paste group (p = 0.025), but the values in the aluminium oxide polishing paste and silicon carbide brush groups were comparable with those in the control group (p = 0.156 and p = 1.000, respectively). The highest surface free energy values were recorded in the silicon carbide brush group (p < 0.001), whereas there were no differences found among the other groups (p > 0.05). The highest BBF was seen in the silicon carbide brush (p < 0.001) and direct CRM (p < 0.001) groups.<br><br>CONCLUSION: BBF on the surface of direct CRMs differed from that on indirect CRMs after polishing the surface. The tested polishing techniques significantly influenced surface properties and BBF.<br><br>CLINICAL SIGNIFICANCE: In situations that require the intraoral adjustment of CRMs, polishing with a diamond polishing paste seems to be a good option to polish the surface of both direct and indirect CRMs because the diamond polishing paste results better in terms of decreasing biofilm formation and improving surface properties.},
}
@article {pmid31556843,
year = {2019},
author = {Horváthová, T and Bauchinger, U},
title = {Biofilm Improves Isopod Growth Independent of the Dietary Cellulose Content.},
journal = {Physiological and biochemical zoology : PBZ},
volume = {92},
number = {6},
pages = {531-543},
doi = {10.1086/705441},
pmid = {31556843},
issn = {1537-5293},
abstract = {Cellulose is an abundant source of carbon, accounting for more than 50% of foliage and 90% of woody tissues of plants. Despite the diversity of species that include living or dead plant tissue in their diets, the ability to digest cellulose through self-produced enzymatic machinery is considered rare in the animal kingdom. The majority of animals studied to date rely on the cellulolytic activity of symbiotic microorganisms in their digestive tract, with some evidence for a complementary action of endogenous cellulases. Terrestrial isopods have evolved a lifestyle including feeding on a lignocellulose diet. Whether isopods utilize both external and internal cellulases for digestion of a diet is still not understood. We experimentally manipulated the content of cellulose (30%, 60%, or 90%) and the amount of biofilm (small or large) in the offered food source and quantified growth and cellulolytic activity in the gut of the isopod Porcellio scaber. The presence of a visible biofilm significantly promoted isopod growth, regardless of the cellulose content in the diet. The activity of gut cellulases was not significantly affected by the amount of biofilm or the cellulose content. Our results do not support a significant contribution of either ingested or host enzymes to cellulose utilization in P. scaber. Cellulose might not represent a key nutrient for isopods and does not seem to affect the nutritional value of the diet-associated biofilm. We propose that it is the biofilm community that determines the quality of plant diet in terrestrial isopods and potentially also in other detrital plant feeders.},
}
@article {pmid31555777,
year = {2019},
author = {Lee, JK and Mereuta, L and Luchian, T and Park, Y},
title = {Antimicrobial peptide HPA3NT3-A2 effectively inhibits biofilm formation in mice infected with drug-resistant bacteria.},
journal = {Biomaterials science},
volume = {},
number = {},
pages = {},
doi = {10.1039/c9bm01051c},
pmid = {31555777},
issn = {2047-4849},
abstract = {Bacterial biofilms formed through secretion of extracellular polymeric substances (EPS) have been implicated in many serious infections and can increase antibiotic resistance by a factor of more than 1000. Here, we examined the abilities of the antimicrobial peptide HPA3NT3-A2 to inhibit and reduce biofilm formation, eliminate EPS, and suppress inflammation in mice infected with clinical isolates of drug-resistant Pseudomonas aeruginosa strains. HPA3NT3-A2 was developed from a desirable analogue peptide, HPA3NT3, derived from residues 2-20 of the Helicobacter pylori ribosomal protein L1. HPA3NT3-A2 showed stronger activity against planktonic cells (MIC: 8 μM) compared to ciprofloxacin or tobramycin (>512 μM), and a favorable minimum biofilm inhibition and elimination concentration. This peptide also neutralized LPS; decreased levels of EPS; inhibited the production of pro-inflammatory cytokines in the lung, kidney, and spleen; decreased white blood cell counts; and increased survival among infected mice.},
}
@article {pmid31553873,
year = {2019},
author = {Sommer, R and Rox, K and Wagner, S and Hauck, D and Henrikus, S and Newsad, S and Arnold, T and Ryckmans, T and Brönstrup, M and Imberty, A and Varrot, A and Hartmann, RW and Titz, A},
title = {Anti-Biofilm Agents against Pseudomonas aeruginosa: a Structure-Activity Relationship Study of C-Glycosidic LecB Inhibitors.},
journal = {Journal of medicinal chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.jmedchem.9b01120},
pmid = {31553873},
issn = {1520-4804},
abstract = {Biofilm formation is a key mechanism of antimicrobial resistance. We have recently reported two classes of orally bioavailable C-glycosidic inhibitors of the Pseudomonas aeruginosa lectin LecB with anti-biofilm activity. They proved efficient in target binding, were metabolically stable, non-toxic, selective and potent in inhibiting formation of bacterial biofilm. Here, we designed and synthesized 6 new carboxamides and 24 new sulfonamides for a detailed structure-activity-relationship for two clinically representative LecB variants. Sulfonamides generally showed higher inhibition compared to carboxamides which was rationalized based on crystal structure analyses. Substitutions at the thiophenesulfonamide increased binding through extensive contacts with a lipophilic protein patch. These metabolically stable compounds showed a further increase in potency towards the target and in biofilm inhibition assays. In general, we established the structure-activity relationship for these promising anti-biofilm agents and showed that modification of the sulfonamide residue bears future optimization potential.},
}
@article {pmid31552285,
year = {2019},
author = {Kaldhone, PR and Carlton, A and Aljahdali, N and Khajanchi, BK and Sanad, YM and Han, J and Deck, J and Ricke, SC and Foley, SL},
title = {Evaluation of Incompatibility Group I1 (IncI1) Plasmid-Containing Salmonella enterica and Assessment of the Plasmids in Bacteriocin Production and Biofilm Development.},
journal = {Frontiers in veterinary science},
volume = {6},
number = {},
pages = {298},
doi = {10.3389/fvets.2019.00298},
pmid = {31552285},
issn = {2297-1769},
abstract = {Mobile genetic elements, such as plasmids, can potentially increase the ability of bacteria to infect and persist in vertebrate host cells. IncI1 plasmids are widely distributed in Salmonella from food animal sources and associated with clinically important strains. These plasmids often encode antimicrobial resistance; however, little is known about their impact on the virulence of Salmonella strains. To assess the potential impact of the plasmids on virulence, 43 IncI1-positive Salmonella isolates from human and animal sources were subjected to whole genome sequence (WGS) analyses and evaluated for their abilities to invade and persist for 48 h in Caco-2 human intestinal epithelial cells, form biofilms and encode bacteriocins. Draft WGS data were submitted to predict the presence of virulence and antimicrobial resistance genes, plasmid replicon types present, conduct plasmid multilocus sequence typing (pMLST), and core genome MLST (cgMLST) in the isolates. Caco-2 cells were infected with Salmonella strains and incubated for both one and 48 h for the invasion and persistence assays, respectively. Additionally, Salmonella isolates and IncI1 plasmid carrying transconjugants (n = 12) generated in Escherichia coli were assessed for their ability to produce biofilms and bacteriocin inhibition of growth of other bacteria. All Salmonella isolates infected Caco-2 cells and persisted in the cells at 48 hrs. Persistent cell counts were observed to be significantly higher than invasion assay cell counts in 26% of the isolates. Among the IncI1 plasmids, there were 18 pMLST types. Nearly 35% (n = 15) of Salmonella isolates produced biofilms; however, none of the IncI1-positive transconjugants produced increased biofilms compared to the recipient. Approximately 65% (n = 28) of isolates and 67% (n = 8) of IncI1-positive transconjugants were able to inhibit growth of at least one E. coli strain; however, none inhibited the growth of strains from species other than E. coli. The study characterized IncI1 positive Salmonella isolates and provided evidence about the potential contributions of IncI1 plasmids virulence phenotypes and areas where they do not. These findings should allow for more focused efforts to assess the impact of plasmids on bacterial pathophysiology and human health.},
}
@article {pmid31552139,
year = {2019},
author = {Willett, JLE and Ji, MM and Dunny, GM},
title = {Exploiting biofilm phenotypes for functional characterization of hypothetical genes in Enterococcus faecalis.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {23},
doi = {10.1038/s41522-019-0099-0},
pmid = {31552139},
issn = {2055-5008},
abstract = {Enterococcus faecalis is a commensal organism as well as an important nosocomial pathogen, and its infections are typically linked to biofilm formation. Nearly 25% of the E. faecalis OG1RF genome encodes hypothetical genes or genes of unknown function. Elucidating their function and how these gene products influence biofilm formation is critical for understanding E. faecalis biology. To identify uncharacterized early biofilm determinants, we performed a genetic screen using an arrayed transposon (Tn) library containing ~2000 mutants in hypothetical genes/intergenic regions and identified eight uncharacterized predicted protein-coding genes required for biofilm formation. We demonstrate that OG1RF_10435 encodes a phosphatase that modulates global protein expression and arginine catabolism and propose renaming this gene bph (biofilm phosphatase). We present a workflow for combining phenotype-driven experimental and computational evaluation of hypothetical gene products in E. faecalis, which can be used to study hypothetical genes required for biofilm formation and other phenotypes of diverse bacteria.},
}
@article {pmid31552130,
year = {2019},
author = {El-Ezmerli, NF and Gregory, RL},
title = {Effect of nicotine on biofilm formation of Streptococcus mutans isolates from smoking and non-smoking subjects.},
journal = {Journal of oral microbiology},
volume = {11},
number = {1},
pages = {1662275},
doi = {10.1080/20002297.2019.1662275},
pmid = {31552130},
issn = {2000-2297},
abstract = {Objectives: To investigate effects of nicotine on biofilm formation of Streptococcus mutans isolates from oral washes of smoker and non-smoker human subjects. Materials and methods: This study was conducted using 60 S. mutans isolates with three S. mutans isolates collected from oral washes of ten smoking subjects and ten from non-smoking subjects. Biofilm was formed by culturing each S. mutans strain (10 μl) in 190 μl of TSB supplemented with 1% sucrose (TSBS) containing 0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0, and 32.0 mg/ml of nicotine for 24 h in 5% CO2 at 37°C in 96 well microtiter plates. The absorbance values of biofilm were measured at 490 nm in a microplate spectrophotometer. Results: There was a significant effect (p-value < 0.05) of nicotine concentrations and smoking on the growth of biofilm, planktonic cells, and total absorbance, for all strains of S. mutans. Isolates from smokers had significantly more biofilm at 0-16 mg/ml of nicotine compared to those from non-smokers (p-value < 0.0001). Conclusion: S. mutans smoker isolates are more affected by high nicotine concentrations than non-smoker isolates. Clinical Relevance: The use of nicotine products increases the growth of S. mutans and may place tobacco users at risk for dental decay.},
}
@article {pmid31551964,
year = {2019},
author = {Selvaraj, A and Jayasree, T and Valliammai, A and Pandian, SK},
title = {Myrtenol Attenuates MRSA Biofilm and Virulence by Suppressing sarA Expression Dynamism.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2027},
doi = {10.3389/fmicb.2019.02027},
pmid = {31551964},
issn = {1664-302X},
abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is a deleterious human pathogen responsible for severe morbidity and mortality worldwide. The pathogen has attained high priority in the World Health Organization (WHO) - Multidrug-resistant (MDR) pathogens list. Emerging MDR strains of S. aureus are clinically challenging due to failure in conventional antibiotic therapy. Biofilm formation is one of the underlying mechanisms behind the antibiotic resistance. Hence, attenuating biofilm formation has become an alternative strategy to control persistent infections. The current study is probably the first that focuses on the antibiofilm and antivirulence potential of myrtenol against MRSA and its clinical isolates. Myrtenol exhibited a concentration-dependent biofilm inhibition without causing any harmful effect on cell growth and viability. Further, microscopic analysis validated the biofilm inhibitory efficacy of myrtenol against MRSA. In addition, myrtenol inhibited the synthesis of major virulence factors including slime, lipase, α-hemolysin, staphyloxanthin and autolysin. Inhibition of staphyloxanthin in turn sensitized the MRSA cells to healthy human blood and hydrogen peroxide (H2O2). Notably, myrtenol treated cells were deficient in extracellular DNA (eDNA) mediated autoaggregation as eDNA releasing autolysis was impaired by myrtenol. Biofilm disruptive activity on preformed biofilms was observed at concentrations higher than minimum biofilm inhibitory concentration (MBIC) of myrtenol. Also, the non-cytotoxic effect of myrtenol on human peripheral blood mononuclear cell (PBMC) was evidenced by trypan blue and Alamar blue assays. Transcriptional analysis unveiled the down-regulation of global regulator sarA and sarA mediated virulence genes upon myrtenol treatment, which is well correlated with results of phenotypic assays. Thus, the results of the present study revealed the sarA mediated antibiofilm and antivirulence potential of myrtenol against MRSA.},
}
@article {pmid31551940,
year = {2019},
author = {Bottagisio, M and Soggiu, A and Piras, C and Bidossi, A and Greco, V and Pieroni, L and Bonizzi, L and Roncada, P and Lovati, AB},
title = {Proteomic Analysis Reveals a Biofilm-Like Behavior of Planktonic Aggregates of Staphylococcus epidermidis Grown Under Environmental Pressure/Stress.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1909},
doi = {10.3389/fmicb.2019.01909},
pmid = {31551940},
issn = {1664-302X},
abstract = {Prosthetic joint replacement failure has a huge impact on quality of life and hospitalization costs. A leading cause of prosthetic joint infection is bacteria-forming biofilm on the surface of orthopedic devices. Staphylococcus epidermidis is an emergent, low-virulence pathogen implicated in chronic infections, barely indistinguishable from aseptic loosening when embedded in a mature matrix. The literature on the behavior of quiescent S. epidermidis in mature biofilms is scarce. To fill this gap, we performed comparative analysis of the whole proteomic profiles of two methicillin-resistant S. epidermidis strains growing in planktonic and in sessile form to investigate the molecular mechanisms underlying biofilm stability. After 72-h culture of biofilm-forming S. epidermidis, overexpression of proteins involved in the synthesis of nucleoside triphosphate and polysaccharides was observed, whereas planktonic bacteria expressed proteins linked to stress and anaerobic growth. Cytological analysis was performed to determine why planktonic bacteria unexpectedly expressed proteins typical of sessile culture. Images evidenced that prolonged culture under vigorous agitation can create a stressful growing environment that triggers microorganism aggregation in a biofilm-like matrix as a mechanism to survive harsh conditions. The choice of a unique late time point provided an important clue for future investigations into the biofilm-like behavior of planktonic cells. Our preliminary results may inform comparative proteomic strategies in the study of mature bacterial biofilm. Finally, there is an increasing number of studies on the aggregation of free-floating bacteria embedded in an extracellular matrix, prompting the need to gain further insight into this mode of bacterial growth.},
}
@article {pmid31551455,
year = {2019},
author = {Valliammai, A and Sethupathy, S and Priya, A and Selvaraj, A and Bhaskar, JP and Krishnan, V and Pandian, SK},
title = {5-Dodecanolide interferes with biofilm formation and reduces the virulence of Methicillin-resistant Staphylococcus aureus (MRSA) through up regulation of agr system.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {13744},
doi = {10.1038/s41598-019-50207-y},
pmid = {31551455},
issn = {2045-2322},
abstract = {Methicillin resistant Staphylococcus aureus (MRSA) is a predominant human pathogen with high morbidity that is listed in the WHO high priority pathogen list. Being a primary cause of persistent human infections, biofilm forming ability of S. aureus plays a pivotal role in the development of antibiotic resistance. Hence, targeting biofilm is an alternative strategy to fight bacterial infections. The present study for the first time demonstrates the non-antibacterial biofilm inhibitory efficacy of 5-Dodecanolide (DD) against ATCC strain and clinical isolates of S. aureus. In addition, DD is able to inhibit adherence of MRSA on human plasma coated Titanium surface. Further, treatment with DD significantly reduced the eDNA synthesis, autoaggregation, staphyloxanthin biosynthesis and ring biofilm formation. Reduction in staphyloxanthin in turn increased the susceptibility of MRSA to healthy human blood and H2O2 exposure. Quantitative PCR analysis revealed the induced expression of agrA and agrC upon DD treatment. This resulted down regulation of genes involved in biofilm formation such as fnbA and fnbB and up regulation of RNAIII, hld, psmα and genes involved in biofilm matrix degradation such as aur and nuc. Inefficacy of DD on the biofilm formation of agr mutant further validated the agr mediated antibiofilm potential of DD. Notably, DD was efficient in reducing the in vivo colonization of MRSA in Caenorhabditis elegans. Results of gene expression studies and physiological assays unveiled the agr mediated antibiofilm efficacy of DD.},
}
@article {pmid31551152,
year = {2019},
author = {Qi, M and Li, X and Sun, X and Li, C and Tay, FR and Weir, MD and Dong, B and Zhou, Y and Wang, L and Xu, HHK},
title = {Novel nanotechnology and near-infrared photodynamic therapy to kill periodontitis-related biofilm pathogens and protect the periodontium.},
journal = {Dental materials : official publication of the Academy of Dental Materials},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.dental.2019.08.115},
pmid = {31551152},
issn = {1879-0097},
abstract = {OBJECTIVE: Periodontal tissue destruction and tooth loss are increasingly a worldwide problem as the population ages. Periodontitis is caused by bacterial infection and biofilm plaque buildup. Therefore, the objectives of this study were to: (1) develop a near-infrared light (NIR)-triggered core-shell nanostructure of upconversion nanoparticles and TiO2 (UCNPs@TiO2), and (2) investigate its inhibitory effects via antibacterial photodynamic therapy (aPDT) against periodontitis-related pathogens.<br><br>METHODS: The core β-NaYF4:Yb3+,Tm3+ were synthesized via thermal decomposition and further modified with the TiO2 shell via a hydrothermal method. The core-shell structure and the upconversion fluorescence-induced aPDT treatment via 980nm laser were studied. Three periodontitis-related pathogens Streptococcus sanguinis (S. sanguinis), Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum) were investigated. The killing activity against planktonic bacteria was detected by a time-kill assay. Single species 4-day biofilms on dentin were tested by live/dead staining, colony-forming units (CFU), and metabolic activity.<br><br>RESULTS: The hexagonal shaped UCNPs@TiO2 had an average diameter of 39.7nm. UCNPs@TiO2 nanoparticles had positively charged (+12.4mV) surface and were biocompatible and non-cytotoxic. Under the excitation of NIR light (980nm), the core NaYF4:Yb3+,Tm3+ UCNPs could emit intense ultraviolet (UV) light, which further triggered the aPDT function of the shell TiO2 via energy transfer, thereby realizing the remarkable antibacterial effects against planktons and biofilms of periodontitis-associated pathogens. NIR-triggered UCNPs@TiO2 achieved much greater reduction in biofilms than control (p<0.05). Biofilm CFU was reduced by 3-4 orders of magnitude via NIR-triggered aPDT, which is significantly greater than that of negative control and commercial aPDT control groups. The killing efficacy of UCNPs@TiO2-based aPDT against the three species was ranked to be: S. sanguinis<F. nucleatum=P. gingivalis. Metabolic activities of biofilms were also greatly reduced via NIR-triggered aPDT (p<0.05).<br><br>SIGNIFICANCE: Upconversion fluorescence-based aPDT achieved strong inhibiting effects against all three species of periodontitis-related pathogens. This novel nanotechnology demonstrated a high promise to inhibit periodontitis, with exciting potential to combat other oral infectious diseases such as deep endodontic infections.},
}
@article {pmid31550929,
year = {2019},
author = {de Freitas, LM and Lorenzón, EN and Cilli, EM and de Oliveira, KT and Fontana, CR and Mang, TS},
title = {Photodynamic and peptide-based strategy to inhibit Gram-positive bacterial biofilm formation.},
journal = {Biofouling},
volume = {35},
number = {7},
pages = {742-757},
doi = {10.1080/08927014.2019.1655548},
pmid = {31550929},
issn = {1029-2454},
abstract = {The self-produced extracellular polymeric matrix of biofilms renders them difficult to eliminate once they are established. This makes the inhibition of biofilm formation key to successful treatment of biofilm infection. Antimicrobial photodynamic therapy (aPDT) and antimicrobial peptides offer a new approach as antibiofilm strategies. In this study sub-lethal doses of aPDT (with chlorin-e6 (Ce6-PDT) or methylene blue (MB-PDT)) and the peptides AU (aurein 1.2 monomer) or (AU)2K (aurein 1.2 C-terminal dimer) were combined to evaluate their ability to prevent biofilm development by Enterococcus faecalis. Biofilm formation was assessed by resazurin reduction, confocal microscopy, and infrared spectroscopy. All treatments successfully prevented biofilm development. The (AU)2K dimer had a stronger effect, both alone and combined with aPDT, while the monomer AU had significant activity when combined with Ce6-PDT. Additionally, it is shown that the peptides bind to the lipoteichoic acid of the E. faecalis cell wall, pointing to a possible key mechanism of biofilm inhibition.},
}
@article {pmid31550928,
year = {2019},
author = {Werner, BG and Wu, JY and Goddard, JM},
title = {Antimicrobial and antifouling polymeric coating mitigates persistence of Pseudomonas aeruginosa biofilm.},
journal = {Biofouling},
volume = {35},
number = {7},
pages = {785-795},
doi = {10.1080/08927014.2019.1660774},
pmid = {31550928},
issn = {1029-2454},
abstract = {Food wasted due to food spoilage remains a global challenge to the environmental sustainability and security of food supply. In food manufacturing, post-processing contamination of food can occur due to persistent bacterial biofilms, which can be resistant to conventional cleaning and sanitization. The objective was to characterize the efficacy of a polymeric coating in reducing Pseudomonas aeruginosa biofilm establishment and facilitating its removal. Viable cell density of a 48 h biofilm was reduced by 2.10 log cfu cm-2 on the coated surface, compared to native polypropylene. Confocal laser scanning and electron microscopy indicated reductions in mature biofilm viability and thickness on the coated material. The antifouling coating improved cleanability, with ∼2.5 log cfu cm-2 of viable cells remaining after 105 min cleaning by water at 65 °C, compared to 4.5 log cfu cm-2 remaining on native polypropylene. Such coatings may reduce the persistence of biofilms in food processing environments, in support of reducing food spoilage and waste.},
}
@article {pmid31550124,
year = {2019},
author = {Hoque, J and Ghosh, S and Paramanandham, K and Haldar, J},
title = {Charge-Switchable Polymeric Coating Kills Bacteria and Prevents Biofilm Formation In vivo.},
journal = {ACS applied materials &amp; interfaces},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsami.9b11453},
pmid = {31550124},
issn = {1944-8252},
abstract = {Preventing bacterial biofilm formation on medical devices and implants in vivo still remains a daunting task. Current antibacterial coatings to combat implant-associated infections are generally composed of toxic metals or non-degradable polymers and involve multistep surface modifications. Here we present a charge-switchable antibacterial and antibiofilm coating based on water-insoluble cationic hydrophobic polymers that are soluble in organic solvents and can be non-covalently coated onto different surfaces. Towards this, a library of quaternary polyethylenimine (QPEI) polymers with amide or ester group in their pendant alkyl chain was developed. These QPEIs are shown to hydrolyze from active cationic to non-toxic zwitterionic polymers under acidic or enzymatic conditions. Notably polymers with both zwitterionic and cationic groups, obtained upon incomplete hydrolysis of QPEIs, are shown to retain their antibacterial activity with much lower toxicity towards mammalian cells. Furthermore the zwitterionic polymer, fully hydrolyzed product of the QPEIs, is shown to be non-toxic to mammalian cells in vitro as well as in vivo. The QPEIs-coated surfaces are shown to kill bacteria and prevent formation of biofilm. In an in vivo mice model, the QPEIs-coated medical grade catheter is shown to reduce methicillin-resistant Staphylococcus aureus (MRSA) contamination both on the catheter surface and in the adjacent tissues (99.99% reduction compared to non-coated catheter). Additionally, biofilm formation is inhibited on the catheter surface with negligible inflammation in the adjacent tissue. The above results thus highlight the importance of these polymers to be used as effective antibacterial coatings in biomedical applications.},
}
@article {pmid31548684,
year = {2019},
author = {Kowalski, CH and Kerkaert, JD and Liu, KW and Bond, MC and Hartmann, R and Nadell, CD and Stajich, JE and Cramer, RA},
title = {Fungal biofilm morphology impacts hypoxia fitness and disease progression.},
journal = {Nature microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1038/s41564-019-0558-7},
pmid = {31548684},
issn = {2058-5276},
support = {5T32 GM 8704-20//U.S. Department of Health &amp; Human Services | NIH | National Institute of General Medical Sciences (NIGMS)/ ; P20-GM113132//U.S. Department of Health &amp; Human Services | NIH | National Institute of General Medical Sciences (NIGMS)/ ; F31AI138354//U.S. Department of Health &amp; Human Services | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/ ; R01AI130128//U.S. Department of Health &amp; Human Services | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/ ; 2R01AI081838//U.S. Department of Health &amp; Human Services | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/ ; MCB 1817342//NSF | BIO | Division of Molecular and Cellular Biosciences (MCB)/ ; Burke Award//Dartmouth College (Dartmouth)/ ; STANTO15RO//Cystic Fibrosis Foundation (CF Foundation)/ ; DBI-1429826//NSF | BIO | Division of Biological Infrastructure (DBI)/ ; S10-OD016290//U.S. Department of Health &amp; Human Services | NIH | NIH Office of the Director (OD)/ ; },
abstract = {Microbial populations form intricate macroscopic colonies with diverse morphologies whose functions remain to be fully understood. Despite fungal colonies isolated from environmental and clinical samples revealing abundant intraspecies morphological diversity, it is unclear how this diversity affects fungal fitness and disease progression. Here we observe a notable effect of oxygen tension on the macroscopic and biofilm morphotypes of the human fungal pathogen Aspergillus fumigatus. A hypoxia-typic morphotype is generated through the expression of a subtelomeric gene cluster containing genes that alter the hyphal surface and perturb interhyphal interactions to disrupt in vivo biofilm and infection site morphologies. Consequently, this morphotype leads to increased host inflammation, rapid disease progression and mortality in a murine model of invasive aspergillosis. Taken together, these data suggest that filamentous fungal biofilm morphology affects fungal-host interactions and should be taken into consideration when assessing virulence and host disease progression of an isolated strain.},
}
@article {pmid31548510,
year = {2019},
author = {Lin, Q and Sun, H and Yao, K and Cai, J and Ren, Y and Chi, Y},
title = {The Prevalence, Antibiotic Resistance and Biofilm Formation of Staphylococcus aureus in Bulk Ready-To-Eat Foods.},
journal = {Biomolecules},
volume = {9},
number = {10},
pages = {},
doi = {10.3390/biom9100524},
pmid = {31548510},
issn = {2218-273X},
abstract = {The prevalence of Staphylococcus aureus in 2160 bulk ready-to-eat foods from the Sichuan province of China during 2013-2016 was investigated. The antibiotic resistance and the associated genes, as well as biofilm formation capacity of the S. aureus isolates were measured. Furthermore, the relationship between the antibiotic resistance and the resistant genes was discussed. It was found that 54 S. aureus isolates were recovered, and their prevalence in meat products, dairy, fruit and vegetables, and desserts were 31 (2.6%), six (3.0%), nine (2.2%) and eight (2.3%), respectively. Most strains (52/54) were resistant to at least one of the antibiotics, and 21 isolates were identified as multidrug-resistant (MDR) S. aureus. Three isolates were found to be methicillin-resistant S. aureus. Penicillin, erythromycin, clindamycin, tetracycline and inducible clindamycin resistance were determined as the predominant antibiotics, and the isolates with the phenotypic resistance on these five antibiotics were all determined positive for the resistant gene associated. In total, 33 of 54 S. aureus isolates showed biofilm formation capacity, including two strong biofilm producers, one moderate and 30 weak ones. Two S. aureus isolates with strong biofilm formation abilities showed multi-drug resistance, and one moderate biofilm producer was resistant to two categories of antibiotics.},
}
@article {pmid31548325,
year = {2019},
author = {Ghimire, N and Pettygrove, BA and Pallister, KB and Stangeland, J and Stanhope, S and Klapper, I and Voyich, JM and Stewart, PS},
title = {Direct Microscopic Observation of Human Neutrophil-Staphylococcus aureus Interaction In Vitro Suggests a Potential Mechanism for Initiation of Biofilm Infection on an Implanted Medical Device.},
journal = {Infection and immunity},
volume = {},
number = {},
pages = {},
doi = {10.1128/IAI.00745-19},
pmid = {31548325},
issn = {1098-5522},
abstract = {The ability of human neutrophils to clear newly attached Staphylococcus aureus bacteria from a serum-coated glass surface was examined in vitro using time-lapse confocal scanning laser microscopy. Quantitative image analysis was used to measure the temporal change in bacterial biomass, neutrophil motility, and fraction of the surface area policed by neutrophils. In control experiments in which the surface was inoculated with bacteria but no neutrophils were added, prolific bacterial growth was observed. Neutrophils were able to control bacterial growth but only consistently when the neutrophil:bacteria number ratio exceeded approximately one. When pre-attached bacteria were given a head start and allowed to grow for three hours prior to neutrophil addition, neutrophils were unable to maintain control of the nascent biofilm. In these head start experiments, aggregates of bacterial biofilm with areas of 50 μm2 or larger formed and the growth of such aggregates continued even when multiple neutrophils attacked a cluster. These results suggest a model for the initiation of a biofilm infection in which a delay in neutrophil recruitment to an abiotic surface allows surface-attached bacteria time to grow and form aggregates that become protected from neutrophil clearance. Results from a computational model of the neutrophil-biofilm surface contest supported this conceptual model and highlighted the stochastic nature of the interaction. Additionally, we observed that both neutrophil motility and clearance of bacteria were impaired when oxygen tension was reduced to 0% or 2% O2SIGNIFICANCE Bacteria or yeast that form biofilms on implanted medical devices such as artificial hip joints cause troublesome infections. These device-associated infections are persistent because biofilm-embedded microorganisms are protected from antibiotics and host defenses. Three decades of research in antimicrobial coatings and non-stick surfaces have not yet solved the biofilm infection problem. Here we show in a model system that neutrophils can effectively clear contaminating Staphylococcus aureus bacteria from an abiotic surface, but they must be delivered quickly and in sufficient numbers. If neutrophil recruitment is delayed, undiscovered bacteria grow and form aggregates that evade engulfment and killing by white blood cells. This work opens a pathway to preventing infections on implanted medical devices by transiently boosting innate immune defenses.},
}
@article {pmid31547513,
year = {2019},
author = {Erdmann, J and Thöming, JG and Pohl, S and Pich, A and Lenz, C and Häussler, S},
title = {The Core Proteome of Biofilm-Grown Clinical Pseudomonas aeruginosa Isolates.},
journal = {Cells},
volume = {8},
number = {10},
pages = {},
doi = {10.3390/cells8101129},
pmid = {31547513},
issn = {2073-4409},
support = {724290/ERC_/European Research Council/International ; },
abstract = {Comparative genomics has greatly facilitated the identification of shared as well as unique features among individual cells or tissues, and thus offers the potential to find disease markers. While proteomics is recognized for its potential to generate quantitative maps of protein expression, comparative proteomics in bacteria has been largely restricted to the comparison of single cell lines or mutant strains. In this study, we used a data independent acquisition (DIA) technique, which enables global protein quantification of large sample cohorts, to record the proteome profiles of overall 27 whole genome sequenced and transcriptionally profiled clinical isolates of the opportunistic pathogen Pseudomonas aeruginosa. Analysis of the proteome profiles across the 27 clinical isolates grown under planktonic and biofilm growth conditions led to the identification of a core biofilm-associated protein profile. Furthermore, we found that protein-to-mRNA ratios between different P. aeruginosa strains are well correlated, indicating conserved patterns of post-transcriptional regulation. Uncovering core regulatory pathways, which drive biofilm formation and associated antibiotic tolerance in bacterial pathogens, promise to give clues to interactions between bacterial species and their environment and could provide useful targets for new clinical interventions to combat biofilm-associated infections.},
}
@article {pmid31547458,
year = {2019},
author = {Zhang, XY and Sun, K and Abulimiti, A and Xu, PP and Li, ZY},
title = {Microfluidic System for Observation of Bacterial Culture and Effects on Biofilm Formation at Microscale.},
journal = {Micromachines},
volume = {10},
number = {9},
pages = {},
doi = {10.3390/mi10090606},
pmid = {31547458},
issn = {2072-666X},
support = {61674046//National Natural Science Foundation of China/ ; 2017TS04//State Key Laboratory of Urban Water Resource and Environment (Harbin Institute of Technology)/ ; },
abstract = {Biofilms exist in the natural world and applied to many industries. However, due to the variety of characteristics caused by their complex components, biofilms can also lead to membrane fouling and recurrent infections which pose threats to human health. So, to make the best use of their advantages and avoid their disadvantages, knowing the best time and methods for improving or preventing biofilm formation is important. In situ observation without fluorescence labeling in microscale and according to a time scale is useful to research biofilm and confine its formation. In this study, we developed a microfluidic system for real-time observation of bacteria culture and biofilms development at microscale. We cultured E. coli ATCC 25922 on a chip at continuous flow of the velocity, which could promote bacterial formation. Biofilms formation under the condition of adding amoxicillin at different times is also discussed. In addition, the mixed strains from sludge were also cultured on chip, and possible factors in biofilm formation are discussed. Our results show that a microfluidic device could culture microorganisms in continuous flow and accelerate them to adhere to the surface, thereby promoting biofilm formation. Overall, this platform is a useful tool in research on initial biofilm formation, which can contribute to preventing biofouling and infections.},
}
@article {pmid31547282,
year = {2019},
author = {Kerekes, EB and Vidács, A and Takó, M and Petkovits, T and Vágvölgyi, C and Horváth, G and Balázs, VL and Krisch, J},
title = {Anti-Biofilm Effect of Selected Essential Oils and Main Components on Mono- and Polymicrobic Bacterial Cultures.},
journal = {Microorganisms},
volume = {7},
number = {9},
pages = {},
doi = {10.3390/microorganisms7090345},
pmid = {31547282},
issn = {2076-2607},
support = {4330//University of Szeged Open Access Fund/ ; },
abstract = {Biofilms are surface-associated microbial communities resistant to sanitizers and antimicrobials. Various interactions that can contribute to increased resistance occur between the populations in biofilms. These relationships are the focus of a range of studies dealing with biofilm-associated infections and food spoilage. The present study investigated the effects of cinnamon (Cinnamomum zeylanicum), marjoram (Origanum majorana), and thyme (Thymus vulgaris) essential oils (EOs) and their main components, i.e., trans-cinnamaldehyde, terpinen-4-ol, and thymol, respectively, on single- and dual-species biofilms of Escherichia coli, Listeria monocytogenes, Pseudomonas putida, and Staphylococcus aureus. In dual-species biofilms, L. monocytogenes was paired with each of the other three bacteria. Minimum inhibitory concentration (MIC) values for the individual bacteria ranged between 0.25 and 20 mg/mL, and trans-cinnamaldehyde and cinnamon showed the highest growth inhibitory effect. Single-species biofilms of L. monocytogenes, P. putida, and S. aureus were inhibited by the tested EOs and their components at sub-lethal concentrations. Scanning electron microscopy images showed that the three-dimensional structure of mature biofilms embedded in the exopolysaccharide matrix disappeared or was limited to micro-colonies with a simplified structure. In most dual-species biofilms, to eliminate living cells from the matrix, concentrations exceeding the MIC determined for individual bacteria were required.},
}
@article {pmid31546523,
year = {2019},
author = {Das, D and Bhattacharjee, H and Gogoi, K and Das, JK and Misra, P and Dhir, P and Deka, A},
title = {Intraocular lens biofilm formation supported by scanning electron microscopy imaging.},
journal = {Indian journal of ophthalmology},
volume = {67},
number = {10},
pages = {1708-1709},
doi = {10.4103/ijo.IJO_467_19},
pmid = {31546523},
issn = {1998-3689},
}
@article {pmid31546354,
year = {2019},
author = {Eduok, U and Ohaeri, E and Szpunar, J},
title = {Accelerated corrosion of pipeline steel in the presence of Desulfovibrio desulfuricans biofilm due to carbon source deprivation in CO2 saturated medium.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {105},
number = {},
pages = {110095},
doi = {10.1016/j.msec.2019.110095},
pmid = {31546354},
issn = {1873-0191},
abstract = {The chemistry of bacterial biofilms as well as the nutritional composition of culture environments may differ at any time within a growth process, especially for SRB consortia within oil wells with limited carbon sources. In the oilfield, the presence of SRB biofilms on surfaces of steel substrates leads to microbiologically influenced corrosion and compromised material integrity. In this work, the survival of SRB cells and their impact on the pipeline steel corrosion within simulated CO2-saturated oilfield-produced water with different concentrations of organic carbon source have been investigated. Cell counts reduced with the level of carbon source reduction (CSR) after incubation but more sessile cells survived at 80% CSR (moderate carbon starvation) compared to 100% CSR (extreme carbon starvation). The energy needed for cellular survival as well as biological support toward MIC could have been harnessed by a combination of extracellular Feo oxidation and intracellular sulfate reduction even after carbon source starvation. Severe anodic steel dissolution was observed at the end of the culture period within the simulated CO2-saturated oilfield-produced water, and this is attributed to SRB-led MIC and CO2 corrosion. Pipeline steel corroded more when cultured within 80% CSR compared to the medium with both lactate and citrate. Steel substrate corroded less with 100% CSR due to severely weakened SRB biofilms from nutrient deprivation.},
}
@article {pmid31546042,
year = {2019},
author = {Sales, LS and Guimarães, GN and Wijesinghe, GK and Silva Moreira, KM and Joia, F and Stipp, RN and Azevedo Rodrigues, LK and Nobre-Dos-Santos, M and Steiner-Oliveira, C},
title = {Addition of hydrogen peroxide to methylene blue conjugated to β-cyclodextrin in photodynamic antimicrobial chemotherapy in S. mutans biofilm.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2019.09.004},
pmid = {31546042},
issn = {1873-1597},
abstract = {OBJECTIVE: This study evaluated the effect of hydrogen peroxide addition on β-cyclodextrin-conjugated methylene blue in photodynamic antimicrobial chemotherapy (PACT) inS. mutans biofilm model using laser or light emitting diode (LED) (λ = 660 nm).<br><br>METHODS: A preliminary assay was performed to evaluate the cytotoxicity of hydrogen peroxide in oral fibroblasts by the colorimetric method (MTT). Afterwards, groups were divided into (n = 3, in triplicate): C (negative control), CX - chlorhexidine 0.2% (positive control), P (methylene blue/β-cyclodextrin), H (Hydrogen Peroxide at 40 µM), PH, L (Laser), LP, LH (Laser+Hydrogen Peroxide), LPH, LED, LEDP, LEDH, and LEDPH. The biofilm was formed in 24 h with BHI + 1% sucrose (w/v). Light irradiations were conducted with laser, 9 J, 323 J/cm2, 113 s or with LED, 8.1 J, 8.1 J/cm2 for 90 s. Microbial reduction was evaluated by counting the viable microorganisms of the biofilm after the respective treatments, in a selective culture medium, and laser confocal microscopy evaluation.<br><br>RESULTS: LP, LH, LPH, LEDP, LEDH, and LEDPH groups statistically reduced the counts ofS. mutans compared with the C group and the log reductions were of 1.87, 1.94, 2.19, 0.91, 0.92, and 1.33, respectively; the addition of hydrogen peroxide did not potentiate the microbial reductions (LPH and LEDPH) compared with the LP and LEDP groups.<br><br>CONCLUSION: The association of hydrogen peroxide with the conjugated β-cyclodextrin nanoparticle as photosensitizer did not result in an enhanced effect of PACT; hydrogen peroxide behaved as a photosensitizer, since it reduced the number ofS. mutans when associated with laser light.},
}
@article {pmid31546040,
year = {2019},
author = {Ram, MK and Naveen Kumar, BT and Poojary, SR and Abhiman, PB and Patil, P and Ramesh, KS and Shankar, KM},
title = {Evaluation of biofilm of Vibrio anguillarum for oral vaccination of Asian seabass, Lates calcarifer (BLOCH, 1790).},
journal = {Fish &amp; shellfish immunology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.fsi.2019.09.053},
pmid = {31546040},
issn = {1095-9947},
abstract = {The present study evaluated the biofilm (BF) of Vibrio anguillarum for oral vaccination of Asian seabass, Lates calcarifer. An 80-day experiment was carried out in circular fiber-reinforced plastic (FRP) tanks using free cell (FC) and BF of Vibrio anguillarum with triplicate in each. Heat-inactivated FC and BF cells at 107, 1010 and 1013 CFU/g fish/d were fed to fish for 20 days, agglutination antibody titer estimated at each 10 days interval up to 60-day post vaccination. As compared to FC and control there was a significant increase in agglutinating antibody titer in the biofilm vaccinated fishes. Among the 3 doses, BF at 1010 cfu/g fish/d was considered the ideal dose for vaccination. Relative percentage survival (RPS) was higher in biofilm vaccinated fish (85.4%) compared to that with free cells (27.0%). The study demonstrated the better performance of V. anguillarum biofilm oral vaccine compared that with free cell vaccine in L. calcarifer. The study further supports better performance of biofilm vaccine model with one more bacterial pathogen in a high carnivore fish.},
}
@article {pmid31546000,
year = {2019},
author = {Campos-Silva, R and Roberta, BF and Silva, TD and Macedo, AJ},
title = {Alternative method in Galleria mellonella larvae to study biofilm infection and treatment.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {103756},
doi = {10.1016/j.micpath.2019.103756},
pmid = {31546000},
issn = {1096-1208},
abstract = {In vivo studies are crucial decision-maker step in order to translate in vitro data to an applied therapy. Considering this we describe a simple method that analyzes and quantifies biofilm formation inside the Galleria mellonella larvae. Toothbrush bristles were employed as an abiotic surface to mimic a medical device. A standardized inoculum of Staphylococcus aureus was systemically injected in the larvae together with the insertion of a bristle in the last proleg pair. After incubation adhered cells were detached from bristles and quantified by colony-forming units (CFU) counting using staphylococci-selective medium. About 3 × 106 CFU of S. aureus were recovered from bristles and scanning electron microscopy images confirmed biofilm formation. Control group did not show adherent bacteria, as demonstrated by absence of CFU counting and SEM images, indicating that the insertion procedure is free of bacterial contamination. We present a feasible method to evaluate bacterial biofilm formation in vivo that in the near future can be used to evaluate antibiofilm compounds.},
}
@article {pmid31543874,
year = {2019},
author = {De Carolis, E and Soldini, S and La Rosa, M and Nucci, F and Posteraro, B and Sanguinetti, M},
title = {BIOF-HILO Assay: A New MALDI-TOF Mass Spectrometry Based Method for Discriminating Between High- and Low-Biofilm-Producing Candida parapsilosis Isolates.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2046},
doi = {10.3389/fmicb.2019.02046},
pmid = {31543874},
issn = {1664-302X},
abstract = {Candida parapsilosis is the most frequent cause of catheter-related candidemia among non-Candida albicans species. This may be related to intrinsic capabilities as adhering and forming a biofilm on abiotic surfaces such as on medical devices. As previously demonstrated, patients infected with high biofilm-producing C. parapsilosis isolates had a greater mortality risk compared to patients infected with low biofilm-producing C. parapsilosis isolates. We developed the BIOF-HILO assay, a MALDI-TOF mass spectrometry (MS)-based assay, which compares mass spectra obtained from attached and suspended isolate cells during the early (i.e., 3-h) adhesion phase of in vitro biofilm formation. The composite correlation index (CCI) analysis was used to discriminate between mass spectra differences of the two cell types, classifying all 50 C. parapsilosis clinical isolates, included in the study, after only 3-h of testing, in high or low biofilm producers. All high (n = 25) or low (n = 25) biofilm producers had, according to CCI mass spectra comparison values, higher or lower than one CCI ratios, which were obtained by dividing the CCIsuspended cells by the CCIattached cells. In conclusion, the BIOF-HILO assay allows a rapid categorization of C. parapsilosis clinical isolates in high or low biofilm producers. This information, if timely provided to physicians, may improve treatment outcomes in patients with C. parapsilosis candidemia.},
}
@article {pmid31543873,
year = {2019},
author = {Alviz-Gazitua, P and Fuentes-Alburquenque, S and Rojas, LA and Turner, RJ and Guiliani, N and Seeger, M},
title = {Corrigendum: The Response of Cupriavidus metallidurans CH34 to Cadmium Involves Inhibition of the Initiation of Biofilm Formation, Decrease in Intracellular c-di-GMP Levels, and a Novel Metal Regulated Phosphodiesterase.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2014},
doi = {10.3389/fmicb.2019.02014},
pmid = {31543873},
issn = {1664-302X},
abstract = {[This corrects the article DOI: 10.3389/fmicb.2019.01499.].},
}
@article {pmid31543653,
year = {2019},
author = {Kitti, T and Seng, R and Thummeepak, R and Boonlao, C and Jindayok, T and Sitthisak, S},
title = {Biofilm Formation of Methicillin-resistant Coagulase-Negative Staphylococci Isolated from Clinical Samples in Northern Thailand.},
journal = {Journal of global infectious diseases},
volume = {11},
number = {3},
pages = {112-117},
doi = {10.4103/jgid.jgid_118_18},
pmid = {31543653},
issn = {0974-777X},
abstract = {Background: Methicillin-resistant coagulase-negative staphylococci (MR-CoNS) are multidrug-resistant bacteria that are difficult to treat because of their ability to form biofilms.<br><br>Objectives: In the present study, we evaluated the antibiotic-resistant phenotypes, biofilm-forming ability, and biofilm associated genes of 55 clinical MR-CoNS isolates obtained from two hospitals in Thailand.<br><br>Materials and Methods: MALDI-TOF-MS and tuf gene sequencing were performed to determine the species of all isolates. Biofilm production was determined using Congo red agar (CRA) and the microtiter plate (MTP) assay. Biofilm-associated genes were characterized using polymerase chain reaction (PCR).<br><br>Results: Among the 55 MR-CoNS isolates, five species were identified as Staphylococcus haemolyticus (34.5%), Staphylococcus epidermidis (32.7%), Staphylococcus capitis (18.2%), Staphylococcus cohnii (9.1%), and Staphylococcus hominis (5.5%). The antimicrobial susceptibility pattern of MR-CoNS isolates indicated high resistance to cefoxitin (100%), penicillin (98.2%), erythromycin (96.4%), ciprofloxacin (67.3%), sulfamethoxazole/trimethoprim (67.3%), gentamicin (67.3%), and clindamycin (63.6%). All the isolates were susceptible to vancomycin and linezolid. The biofilm production was detected in 87.3% isolates through the CRA method and in 38.1% isolates through the MTP assay. The prevalence rates of icaAD, bap, fnbA, and cna were 18.2%, 12.7%, 47.3%, and 27.3%, respectively. There were significant differences in the presence of these biofilm-associated genes among the MR-CoNS isolates. Moreover, quantitative biofilm formation was significantly different among MR-CoNS species.<br><br>Conclusion: The present study revealed that biofilm-associated genes are important for biofilm biomass in MR-CoNS isolates, and the findings of this study are essential for finding new strategies to control biofilm formation and prevent the spread of MR-CoNS infectious diseases.},
}
@article {pmid31542601,
year = {2019},
author = {Mitchell, K and Lima, AT and Van Cappellen, P},
title = {Selenium in buoyant marine debris biofilm.},
journal = {Marine pollution bulletin},
volume = {149},
number = {},
pages = {110562},
doi = {10.1016/j.marpolbul.2019.110562},
pmid = {31542601},
issn = {1879-3363},
abstract = {Marine debris is widespread in all the world's oceans. Currently little is understood about how marine debris affects the chemistry of the surface oceans, particularly trace elements that can adsorb to the surface of marine debris, especially plastic debris, or be taken up by biofilms and algae growing on the surface of marine debris. Selenium (Se) is a micronutrient that is essential to all living organisms. Average seawater Se concentrations in the modern ocean are <1 nM. Here we measure the concentration of Se in surface water and one deep water sample and the concentration of Se found in algae/biofilms growing on the surface of macro-debris collected in October of 2012. Concentrations of Se in biofilm varied more according to the type of biofilm rather than the type of plastic. However, further Se measurements are needed for more conclusive results.},
}
@article {pmid31542551,
year = {2019},
author = {Acevedo Alonso, V and Lackner, S},
title = {Membrane Aerated Biofilm Reactors - How longitudinal gradients influence nitrogen removal - A conceptual study.},
journal = {Water research},
volume = {166},
number = {},
pages = {115060},
doi = {10.1016/j.watres.2019.115060},
pmid = {31542551},
issn = {1879-2448},
abstract = {Membrane-aerated biofilm reactors are becoming more important for nitrogen removal in the wastewater sector. One-dimensional (1D) models are widely used to study the performance of such systems; however, 1D models are not able to simulate the longitudinal gradients that exist in the reactor. Although there is experimental evidence that points to the existence of longitudinal gradients simple modeling approaches that consider these gradients are not yet developed. This study proposes a novel multi-compartment model that simulates the longitudinal substrate and oxygen gradients. It assesses the effects of temperature, biofilm thickness, number of compartments, and flow configuration (liquid and gas phase) on the modeling results. Additionally, it compares the capabilities of a traditional 1D model with those of the novel multi-compartment model. Our results show that a classical 1D model predicts a lower total dissolved nitrogen concentration (TDN) in the effluent in contrast to the predictions of the multi-compartment model. In the worst-case scenario, the TDN predicted by the traditional 1D model was three times lower than the prediction of the multi-compartment model. The results delivered by the models differ also in the axial gradients. The traditional 1D model, for example, predicted an oxygen concentration at the membrane surface of 0.4 mg-O2/l while the multi-compartment model predicted a concentration of 2.9 mg-O2/l. Finally, the results of this study show that the longitudinal oxygen gradient has an important effect on both, biomass distribution and effluent TDN, whereas the longitudinal substrate exclusively affected the effluent TDN.},
}
@article {pmid31541515,
year = {2019},
author = {Amaechi, BT and Abdul Azees, PA and Menon, S and Kasundra, H},
title = {In vitro evaluation of the effects of Ultrasound Tongue Scraper on bacteria and biofilm formation.},
journal = {Journal of investigative and clinical dentistry},
volume = {},
number = {},
pages = {e12471},
doi = {10.1111/jicd.12471},
pmid = {31541515},
issn = {2041-1626},
support = {//Starmoon/ ; },
abstract = {AIM: Oral malodor is a common condition caused by some Gram-negative oral bacteria, among which are the 3 red complex bacteria (RCB). The present study investigated the effectiveness of the Ultrasound Tongue Scraper (UTS) to disrupt the structural morphology of the bacteria and their biofilm.<br><br>METHODS: While developing over 72 hours, multispecies biofilms of RCB (Porphromonas gingivalis, Tryponema denticola, Tannerella forsythia) were treated every 24 hours with 1.6-MHz ultrasound waves generated with UTS. An untreated group served as controls. Confocal laser scanning microscopy was used to determine the biofilm thickness, biomass and live : dead cell ratio at each time point (24, 48 and 72 hours). Biofilm morphology and bacteria ultrastructure were viewed using scanning/transmission electron microscopy, respectively. Data were analyzed using ANOVA and Tukey tests.<br><br>RESULTS: At each time point, the 3 variables were significantly lower in treated samples than the untreated. Significant biofilm disruption was observed in treated samples at each time period while the untreated had intact biofilm morphology. Cells in treated samples showed disrupted cell wall, cytoplasmic material, huge vacuoles and heterogeneity in electron density, while these cell organelles remained intact in untreated samples.<br><br>CONCLUSION: The UTS has an inhibitory effect on RCB and could be useful for oral malodor management.},
}
@article {pmid31540110,
year = {2019},
author = {Li, S and Wang, Y and Li, X and Lee, BS and Jung, S and Lee, MS},
title = {Enhancing the Thermo-Stability and Anti-Biofilm Activity of Alginate Lyase by Immobilization on Low Molecular Weight Chitosan Nanoparticles.},
journal = {International journal of molecular sciences},
volume = {20},
number = {18},
pages = {},
doi = {10.3390/ijms20184565},
pmid = {31540110},
issn = {1422-0067},
support = {NRF-2016R1A5A1011974//National Research Foundation of Korea (NRF)/ ; MBSMAT-2019-02//Key Lab of Marine Bioactive Substance and Modern Analytical Technique (SOA)/ ; ZR2019BD027//Shandong Provincial Natural Science Foundation/ ; KLGGOUC201703//Open Research Fund Program of Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology (Ocean University of China)/ ; },
abstract = {Bacterial biofilm causes severe antibiotic resistance. An extracellular polymeric substance (EPS) is the main component in the bacterial biofilm. Alginate is a key EPS component in the biofilm of Pseudomonas aeruginosa and responsible for surface adhesion and stabilization of biofilm. Alginate lyase has emerged as an efficient therapeutic strategy targeting to degrade the alginate in the biofilm of P. aeruginosa. However, the application of this enzyme is limited by its poor stability. In this study, chitosan nanoparticles (CS-NPs) were synthesized using low molecular weight chitosan and alginate lyase Aly08 was immobilized on low molecular weight chitosan nanoparticles (AL-LMW-CS-NPs). As a result, the immobilization significantly enhanced the thermal stability and reusability of Aly08. In addition, compared with free Aly08, the immobilized AL-LMW-CS-NPs exhibited higher efficiency in inhibiting biofilm formation and interrupting the established mature biofilm of P. aeruginosa, which could reduce its biomass and thickness confirmed by confocal microscopy. Moreover, the biofilm disruption greatly increased the antibiotic sensitivity of P. aeruginosa. This research will contribute to the further development of alginate lyase as an anti-biofilm agent.},
}
@article {pmid31539943,
year = {2019},
author = {Wang, X and Liu, B and Pan, X and Gadd, GM},
title = {Transport and retention of biogenic selenium nanoparticles in biofilm-coated quartz sand porous media and consequence for elemental mercury immobilization.},
journal = {The Science of the total environment},
volume = {692},
number = {},
pages = {1116-1124},
doi = {10.1016/j.scitotenv.2019.07.309},
pmid = {31539943},
issn = {1879-1026},
abstract = {Bacterial biofilms are structured cell communities embedded in a matrix of extracellular polymeric substances (EPS) and a ubiquitous growth form of bacteria in the environment. A wide range of interactions between biofilms and nanoparticles have been reported. In the present study, the influence of a mixed bacterial biofilm on retention of biogenic selenium nanoparticles (BioSeNPs) and consequences for immobilization of elemental mercury (Hg0) in a porous quartz sand system were examined. BioSeNPs were significantly retained in the presence of a biofilm through electrical double layer effects, hydrogen bonding, and hydrophobic, steric and bridging interactions. Moreover, enhanced surface roughness, pore clogging, sieving and entrapment effects mediated by the biofilm also contributed to deposition of BioSeNPs. Whereas, thiol groups associated with the biofilm is a little helpful for the capture of Hg0. It is proposed that oxidative complexation between Hg0 and thiol compounds or S containing organic matter in the biofilm may result in the formation of Hg2+-thiolate complexes and HgS during the binding of Hg0 with BioSeNPs. The formation of mercury selenide was also involved in Hg0 immobilization in the porous quartz sand system.},
}
@article {pmid31539312,
year = {2019},
author = {Cai, X and Yao, L and Sheng, Q and Jiang, L and Wang, T and Dahlgren, RA and Deng, H},
title = {Influence of a biofilm bioreactor on water quality and microbial communities in a hypereutrophic urban river.},
journal = {Environmental technology},
volume = {},
number = {},
pages = {1-34},
doi = {10.1080/09593330.2019.1670267},
pmid = {31539312},
issn = {1479-487X},
abstract = {Biofilms play an important role in degradation, transformation and assimilation of anthropogenic pollutants in aquatic ecosystems. In this study, we assembled a tubular bioreactor containing a biofilm substrate and aeration device, which was introduced into mesocosms to explore the effects of bioreactor on physicochemical and microbial characteristics of a hypereutrophic urban river. The biofilm bioreactor greatly improved water quality, especially by decreasing dissolved inorganic nitrogen (DIN) concentrations, suggesting that biofilms were the major sites of nitrification and denitrification with an oxygen concentration gradient. The biofilm bioreactor increased the abundance of planktonic bacteria, whereas diversity of the planktonic microbial community decreased. Sequencing revealed that Proteobacteria, Bacteroidetes, Planctomycetes, and Actinobacteria were the four predominant phyla in the planktonic microbial community, and the presence of the biofilm bioreactor increased the relative abundance of Proteobacteria. Variations in microbial communities were most strongly affected by the presence of the biofilm bioreactor, as indicated by principal component analysis (PCA) and redundancy analysis (RDA). This study provides valuable insights into changes in ecological characteristics associated with self-purification processes in hypereutrophic urban rivers, and and may be of important for the application of biofilm bioreactor in natural urban river.},
}
@article {pmid31537970,
year = {2019},
author = {Bali, EB and Türkmen, KE and Erdönmez, D and Sağlam, N},
title = {Comparative Study of Inhibitory Potential of Dietary Phytochemicals Against Quorum Sensing Activity of and Biofilm Formation by Chromobacterium violaceum 12472, and Swimming and Swarming Behaviour of Pseudomonas aeruginosa PAO1.},
journal = {Food technology and biotechnology},
volume = {57},
number = {2},
pages = {212-221},
doi = {10.17113/ftb.57.02.19.5823},
pmid = {31537970},
issn = {1330-9862},
abstract = {Quorum sensing (QS) and biofilm formation are important mechanisms related to antibiotic resistance of many pathogens. Alternative treatments are needed to prevent recurrent or chronic infections caused by multi-resistant pathogens. Therefore, the aim of this study is to investigate and compare the inhibitory potential of the dietary phytochemicals: curcumin, quercetin, apigenin, pyrogallol, gallic acid and luteolin against QS of and biofilm formation by Chromobacterium violaceum ATCC 12472 and the swimming and swarming abilities of Pseudomonas aeruginosa PAO1. Anti-QS potential of the phytochemicals was evaluated qualitatively and quantitatively using C. violaceum via the disk diffusion assay based on violacein pigment inhibition at the subminimal inhibitory concentrations ranging from 46.87 to 750 µg/mL. The results of anti-QS and antibiofilm activities on C. violaceum demonstrated that all the phytochemicals except pyrogallol and gallic acid inhibited violacein production (from (11.0±0.1) to (88.2±0.1) %) in a concentration-dependent manner. In addition, the biofilm formation was also significantly inhibited (p<0.05) in the presence of all the phytochemicals ((1.38±0.08)-(84.2±0.2) %). In the present study, the results revealed that quercetin, curcumin, apigenin and luteolin could be promising QS and biofilm inhibitory agents against the C. violaceum 12472 biosensor system. Our findings also suggest that all the phytochemicals, especially curcumin, quercetin and pyrogallol, might be anti-pathogenic agents against P. aeruginosa PAO1 infections due to the ability to control QS. However, more comprehensive studies at the molecular level, explaining their anti-QS mechanisms, need to be conducted to confirm these results and identify the genes involved.},
}
@article {pmid31536440,
year = {2019},
author = {Abushahba, F and Söderling, E and Aalto-Setälä, L and Hupa, L and Närhi, TO},
title = {Air-Abrasion with bioactive glass eradicates S. mutans biofilm from sandblasted and acid etched titanium surface.},
journal = {The Journal of oral implantology},
volume = {},
number = {},
pages = {},
doi = {10.1563/aaid-joi-D-18-00324},
pmid = {31536440},
issn = {0160-6972},
abstract = {Streptococcus mutans is able to form a high-affinity biofilm on material surfaces. S. mutans has also been detected around infected implants. Bioactive glasses have been shown to possess antibacterial effects against S. mutans and other microorganisms. This in vitrostudy was performed to investigate the influence of bioactive glass air-abrasion on S. mutans biofilm on sandblasted and acid etched titanium surfaces. Sandblasted and acid etched commercially pure titanium discs were used as substrates for bacteria (n=107). The discs were immersed in an S. mutans solution and incubated for 21 h to form S. mutans biofilm. Twenty colonized discs were subjected to air-abrasion with the Bioglass®45S5 (45S5 BAG), experimental zinc oxide containing bioactive glass (Zn4 BAG) and inert glass. After the abrasion, the discs were incubated for 5 h in an anaerobic chamber followed by an assessment of viable S. mutans cells. Surface morphology was evaluation using SEM (n=12). Thrombogenicity of the glass particle abraded discs (n=75) was evaluated spectrophotometrically using whole blood clotting measurement at predetermined time points. Air-abrasion with 45S5 and Zn4 bioactive glass eradicated S. mutans biofilm. Significantly less viable S. mutans cells were found on discs abraded with the 45S5 or Zn4 BAGs compared to the inert glass (p<0.001). No significant differences were found in thrombogenicity since blood clotting was achieved for all substrates in min 40. Air-abrasion with BAG particles is effective in the eradication of S. mutans biofilm from sandblasted and acid etched titanium surfaces. Zn4 and 45S5 BAGs had similar biofilm eradicating effects but the Zn4 BAG could be more tissue-friendly. In addition, the steady release of zinc ions from the Zn4 may enhance the bone regeneration around the titanium implant and may thus have the potential to be used in the treatment of peri-implantitis. The use of either BAGs did not enhance the speed of blood coagulation.},
}
@article {pmid31535222,
year = {2019},
author = {Mello, DCR and de Oliveira, JR and Cairo, CAA and Ramos, LSB and Vegian, MRDC and de Vasconcellos, LGO and de Oliveira, FE and de Oliveira, LD and de Vasconcellos, LMR},
title = {Titanium alloys: in vitro biological analyzes on biofilm formation, biocompatibility, cell differentiation to induce bone formation, and immunological response.},
journal = {Journal of materials science. Materials in medicine},
volume = {30},
number = {9},
pages = {108},
doi = {10.1007/s10856-019-6310-2},
pmid = {31535222},
issn = {1573-4838},
support = {2012/20311-8//Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)/ ; },
abstract = {Biological effects of titanium (Ti) alloys were analyzed on biofilms of Candida albicans, Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus mutans, and Streptococcus sanguinis, as well as on osteoblast-like cells (MG63) and murine macrophages (RAW 264.7). Standard samples composed of aluminum and vanadium (Ti-6Al-4V), and sample containing niobium (Ti-35Nb) and zirconium (Ti-13Nb-13Zr) were analyzed. Monomicrobial biofilms were formed on the Ti alloys. MG63 cells were grown with the alloys and the biocompatibility (MTT), total protein (TP) level, alkaline phosphatase (ALP) activity, and mineralization nodules (MN) formation were verified. Levels of interleukins (IL-1β and IL-17), tumor necrosis factor alpha (TNF-α), and oxide nitric (NO) were checked, from RAW 264.7 cells supernatants. Data were statically analyzed by one-way analysis of variance (ANOVA) and Tukey's test, or T-test (P ≤ 0.05). Concerning the biofilm formation, Ti-13Nb-13Zr alloy showed the best inhibitory effect on E. faecalis, P. aeruginosa, and S. aureus. And, it also acted similarly to the Ti-6Al-4V alloy on C. albicans and Streptococcus spp. Both alloys were biocompatible and similar to the Ti-6Al-4V alloy. Additionally, Ti-13Nb-13Zr alloy was more effective for cell differentiation, as observed in the assays of ALP and MN. Regarding the stimulation for release of IL-1β and TNF-α, Ti-35Nb and Ti-13Nb-13Zr alloys inhibited similarly the synthesis of these molecules. However, both alloys stimulated the production of IL-17. Additionally, all Ti alloys showed the same effect for NO generation. Thus, Ti-13Nb-13Zr alloy was the most effective for inhibition of biofilm formation, cell differentiation, and stimulation for release of immune mediators.},
}
@article {pmid31535132,
year = {2019},
author = {Oktay, EA and Ersahan, S and Sabuncuoglu, FA and Tort, H and Karaoglanoglu, S},
title = {Impact of various finishing and polishing techniques and composite materials on Candida albicans biofilm formation.},
journal = {Medical mycology},
volume = {},
number = {},
pages = {},
doi = {10.1093/mmy/myz095},
pmid = {31535132},
issn = {1460-2709},
abstract = {Candida albicans biofilms are commonly associated with severe oral infections. In dentistry, prosthetic and restorative materials are potential structures for the adhesion of C. albicans facilitating the formation of Candida biofilm and infection. Three composite resins (Charisma Classic, Sonic Fill, Estelite ∑ Quick) and two finishing-polishing systems (Biscover LV, Dental Finishing Disc) were evaluated for Candida biofilm formation. A Candida biofilm assay showed that both the resin and the finishing/polishing procedures affect Candida biofilm formation. Specifically, Candida biofilm formation was significantly lower in Sonic Fill resin than both Charisma Classic and Estelite ∑ Quick (P = .021). The type of finishing and polishing procedure also significantly affected the Candida biofilm formation to composite material (P < .001). Candida biofilm formation was more advanced after Biscover LV procedure than Dental Finishing Disc procedure.},
}
@article {pmid31534648,
year = {2019},
author = {Craft, KM and Nguyen, JM and Berg, LJ and Townsend, SD},
title = {Methicillin-resistant Staphylococcus aureus (MRSA): antibiotic-resistance and the biofilm phenotype.},
journal = {MedChemComm},
volume = {10},
number = {8},
pages = {1231-1241},
doi = {10.1039/c9md00044e},
pmid = {31534648},
issn = {2040-2511},
abstract = {Staphylococcus aureus (S. aureus) is an asymptomatic colonizer of 30% of all human beings. While generally benign, antibiotic resistance contributes to the success of S. aureus as a human pathogen. Resistance is rapidly evolved through a wide portfolio of mechanisms including horizontal gene transfer and chromosomal mutation. In addition to traditional resistance mechanisms, a special feature of S. aureus pathogenesis is its ability to survive on both biotic and abiotic surfaces in the biofilm state. Due to this characteristic, S. aureus is a leading cause of human infection. Methicillin-resistant S. aureus (MRSA) in particular has emerged as a widespread cause of both community- and hospital-acquired infections. Currently, MRSA is responsible for 10-fold more infections than all multi-drug resistant (MDR) Gram-negative pathogens combined. Recently, MRSA was classified by the World Health Organization (WHO) as one of twelve priority pathogens that threaten human health. In this targeted mini-review, we discuss MRSA biofilm production, the relationship of biofilm production to antibiotic resistance, and front-line techniques to defeat the biofilm-resistance system.},
}
@article {pmid31533204,
year = {2019},
author = {Weng, PL and Ramli, R and Hamat, RA},
title = {Antibiotic Susceptibility Patterns, Biofilm Formation and esp Gene among Clinical Enterococci: Is There Any Association?.},
journal = {International journal of environmental research and public health},
volume = {16},
number = {18},
pages = {},
doi = {10.3390/ijerph16183439},
pmid = {31533204},
issn = {1660-4601},
abstract = {Enterococci are commonly found in humans, animals and environments. Their highly adaptive mechanisms are related to several virulent determinants and their ability to resist antibiotics. Data on the relationship between the esp gene, biofilm formation and antibiotic susceptibility profiles may differ between countries. This cross-sectional study was conducted to determine the proportion of esp gene and biofilm formation among Enterococcus faecalis and Enterococcus faecium clinical isolates. We also investigated the possible association between the esp gene with antibiotic susceptibility patterns and biofilm formation. The isolates were collected from clinical samples and identified using biochemical tests and 16SRNA. Antibiotic susceptibility patterns and a biofilm assay were conducted according to the established guidelines. Molecular detection by PCR was used to identify the esp gene using established primers. In total, 52 and 28 of E. faecalis and E. faecium were identified, respectively. E. faecium exhibited higher resistance rates compared to E. faecalis as follows: piperacillin/tazobactam (100% versus 1.9%), ampicillin (92.8% versus 1.9%), high-level gentamicin resistance (HLGR) (89.3% versus 25.0%) and penicillin (82.1% versus 7.7%). E. faecium produced more biofilms than E. faecalis (59.3% versus 49.0%). E. faecium acquired the esp gene more frequently than E. faecalis (78.6% versus 46.2%). Interestingly, the associations between ampicillin and tazobactam/piperacillin resistance with the esp gene were statistically significant (X2 = 4.581, p = 0.027; and X2 = 6.276, p = 0.012, respectively). Our results demonstrate that E. faecium exhibits high rates of antimicrobial resistance, esp gene acquisition and biofilm formation. These peculiar traits of E. faecium may have implications for the management of enterococcal infections in hospitals. Thus, concerted efforts by all parties in establishing appropriate treatment and effective control measures are warranted in future.},
}
@article {pmid31533083,
year = {2019},
author = {Preetham, E and Rubeena, AS and Vaseeharan, B and Chaurasia, MK and Arockiaraj, J and Olsen, RE},
title = {Anti-biofilm properties and immunological response of an immune molecule lectin isolated from shrimp Metapenaeus monoceros.},
journal = {Fish &amp; shellfish immunology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.fsi.2019.09.032},
pmid = {31533083},
issn = {1095-9947},
abstract = {The study is carried out to understand the antimicrobial and immunological response of a potential immune molecule lectin, MmLec isolated from haemolymph of Speckled shrimp, Metapenaeus monoceros. MmLec was purified using mannose coupled Sepharose CL-4B affinity chromatography, which was further subjected on SDS-PAGE to ascertain the distribution of their molecular weight. Sugar binding specificity assay was conducted at various pH and temperatures to investigate the binding affinity of MmLec towards the specific carbohydrate molecule. Functional analysis of immune molecule MmLec included haemagglutination assays performed using human erythrocytes and yeast agglutination activity against Saccharomyces cerevisiae which, were analyzed using light microscopy. In order to study the antimicrobial activity, two Gram-negative (Vibrio parahaemolyticus and Aeromonas hydrophila) and two Gram-positive (Staphylococcus aureus and Enterococcus faecalis) bacteria were treated with purified MmLec. Moreover, these bacterial species were also treated at different concentration of the MmLec to speculate the antibiofilm properties of MmLec which was analyzed under Light Microscopy and Confocal Laser Scanning Microscopy. In addition, other functional characterization of MmLec showed the uniqueness of MmLec in agglutination of human erythrocyte as well as the cells of yeast Saccharomyces cerevisiae. Also, the phenoloxidase activity and encapsulation assay was evaluated. MTT assay displayed that MmLec are potent in anticancer activity. The study will help to understand the immunological interference and antimicrobial nature of MmLec which would be supportive in establishing a potential therapeutic tool and to develop better and novel disease control strategies in shrimp and farmed aquaculture industries as well as in health management.},
}
@article {pmid31533077,
year = {2019},
author = {Vijayakumar, K and Ramanathan, T},
title = {Musa acuminata and its bioactive metabolite 5-Hydroxymethylfurfural mitigates quorum sensing (las and rhl) mediated biofilm and virulence production of nosocomial pathogen Pseudomonas aeruginosa in vitro.},
journal = {Journal of ethnopharmacology},
volume = {},
number = {},
pages = {112242},
doi = {10.1016/j.jep.2019.112242},
pmid = {31533077},
issn = {1872-7573},
abstract = {Musa acuminata, a tropical plant belongs to the family Musaceae. The fruit peels of this plant have been well documented for their therapeutic value in Asia and Africa. It has also been previously reported for numerous biological applications such as antimicrobial, antioxidant, itching, psoriasis and anti-diarrheal activities. Moreover, M. acuminata peels have been well known for its anti-healing and antiseptic properties and most commonly used for healing wounds and heat burns in South Asian and African traditional medicines.<br><br>AIM OF THE STUDY: To evaluate the QS-mediated antibiofilm and antivirulence potential of M. acuminata, and its bioactive metabolites 5-Hydroxymethylfurfural (5HMF) against Pseudomonas aeruginosa.<br><br>MATERIALS AND METHODS: The M. acuminata peel methanol extract (MAM) was evaluated for its antibiofilm potential against P. aeruginosa with increasing concentration. Besides, biofilm related phenomenon's such as total biofilm proteins, microcolony formation exopolysaccharides (EPS) and cell surface hydrophobicity (CSH) productions were also examined to support the antibiofilm potential of MAM. Further, MAM was evaluated for its antivirulence efficacy against P. aeruginosa by assessing the protease, LasA protease, LasB elastase, pyocyanin, alginate and rhamnolipid productions at 400 μg ml-1 concentration. Transcriptional analysis of QS regulated virulence genes expression level was also done by real-time PCR analysis. Then, the MAM was subjected to column chromatography for further fractions and the bioactive compounds present in MAM were identified by gas chromatograph-mass spectrometry analysis. Further, the major compounds such as 5-hydroxymethylfurfural, vaccenic acid and pentanoic acid identified from active fraction of MAM were evaluated for their antibiofilm and antivirulence potential against P. aeruginosa.<br><br>RESULTS: MAM significantly inhibited the biofilm formation in P. aeruginosa at 400 μg ml-1 concentration which also inhibited the production of biofilm proteins, biofilm adherence, EPS and CSH productions to the level of 79%, 82% and 77% respectively. Further, the antivirulence potential was confirmed through numerous virulence inhibition assays. The MAM at 400 μg ml-1 concentration inhibited the QS-mediated virulence production such as protease, LasA protease, LasB elastase, pyocyanin, alginate and rhamnolipid productions to the level of 77%, 75%, 68%, 80%, 78% and 69% respectively. Moreover, the results of qPCR analysis confirmed the downregulation of QS regulated virulence genes expression upon treatment with MAM. The chromatographic analysis revealed the presence of 5-Hydroxymethylfurfural (5HMF), vaccenic acid and pentanoic acid in MAM and the potential bioactive compounds with antibiofilm and antivirulence was identified as 5-hydroxymethylfurfural, without exerting any growth inhibition in P. aeruginosa.<br><br>CONCLUSION: This study investigated the ideal antibiofilm and antivirulence potential of MAM and its bioactive compound 5HMF, and confirms the ethnopharmacological value of these peels against P. aeruginosa infections.},
}
@article {pmid31532581,
year = {2019},
author = {She, P and Wang, Y and Liu, Y and Tan, F and Chen, L and Luo, Z and Wu, Y},
title = {Effects of exogenous glucose on Pseudomonas aeruginosa biofilm formation and antibiotic resistance.},
journal = {MicrobiologyOpen},
volume = {},
number = {},
pages = {e933},
doi = {10.1002/mbo3.933},
pmid = {31532581},
issn = {2045-8827},
support = {20150309//The New Xiangya Talent Project of The Third Xiangya Hospital of Central South University/ ; },
abstract = {Pseudomonas aeruginosa is commonly found in nosocomial and life-threatening infections in patients. Biofilms formed by P. aeruginosa exhibit much greater resistance to antibiotics than the planktonic form of the bacteria. Few groups have studied the effects of glucose, a major carbon source, and metabolite, on P. aeruginosa biofilm formation and on its metabolic pathways. In this study, we investigated the effect of glucose on the biofilm formation ability of P. aeruginosa and carried out a metabolomic analysis to identify whether glucose alters the metabolic activity of P. aeruginosa in biofilms. We found that glucose efficiently promoted P. aeruginosa biofilm formation by upregulating the expression of the extracellular polysaccharide-related gene pslA. Treatment with glucose caused an increase in 7 metabolites (including 3-hydroxypropionic acid, glucose-6-phosphate, and 2,3-dimethylsuccinic acid) and a decrease in 18 metabolites (including myo-inositol, glutamine, and methoxamedrine) in the biofilm. In addition, there was a synergistic effect between glucose and horse serum on biofilm formation when the two were added in combination, which also increased the resistance of biofilm to levofloxacin therapy. Thus, our work sheds light on the underlying mechanisms by which glucose may enhance biofilm formation and identifies novel targets for developing strategies to counteract biofilm formation.},
}
@article {pmid31532251,
year = {2019},
author = {Wang, H and Palmer, J and Flint, S},
title = {Function of pYV Plasmid on Biofilm Formation of Yersinia enterocolitica ERL032123 in the Presence of Ca2.},
journal = {Journal of food protection},
volume = {},
number = {},
pages = {1683-1687},
doi = {10.4315/0362-028X.JFP-19-018},
pmid = {31532251},
issn = {1944-9097},
abstract = {The effect of the virulence plasmid pYV and calcium ions on biofilm of Yersinia enterocolitica biofilm formation was determined using a microtiter plate assay. Loss of the pYV plasmid prevented biofilm formation and the presence of Ca2+ enhanced biofilm formation in cultures containing the pYV plasmid. Scanning electron microscopy supported the result from the microtiter plate assay showing that in the presence of Ca2+, the wild-type Y. enterocolitica strain formed a strong biofilm on a polycarbonate surface. The results implied that Ca2+ promotes Y. enterocolitica biofilm formation through the function of the pYV plasmid.},
}
@article {pmid31531452,
year = {2019},
author = {Baumeister, TUH and Staudinger, M and Wirgenings, M and Pohnert, G},
title = {Halogenated anilines as novel natural products from a marine biofilm forming microalga.},
journal = {Chemical communications (Cambridge, England)},
volume = {},
number = {},
pages = {},
doi = {10.1039/c9cc05992j},
pmid = {31531452},
issn = {1364-548X},
abstract = {The toxic halogenated anilines 2,4,6-tribromoaniline, 2,4,6-trichloroaniline and their dibromochloro and bromodichloro derivatives were considered as compounds of exclusive synthetic origin. Labeling studies and kinetic experiments confirmed that these substances are also biosynthesized by a marine biofilm forming microalga. They represent a novel class of halogenated natural products.},
}
@article {pmid31531409,
year = {2019},
author = {Hwang, G and Paula, AJ and Hunter, EE and Liu, Y and Babeer, A and Karabucak, B and Stebe, K and Kumar, V and Steager, E and Koo, H},
title = {Catalytic antimicrobial robots for biofilm eradication.},
journal = {Science robotics},
volume = {4},
number = {29},
pages = {},
doi = {10.1126/scirobotics.aaw2388},
pmid = {31531409},
issn = {2470-9476},
abstract = {Magnetically driven robots can perform complex functions in biological settings with minimal destruction. However, robots designed to damage deleterious biostructures could also have important impact. In particular, there is an urgent need for new strategies to eradicate bacterial biofilms as we approach a post-antibiotic era. Biofilms are intractable and firmly attached structures ubiquitously associated with drug-resistant infections and destruction of surfaces. Existing treatments are inadequate to both kill and remove bacteria leading to reinfection. Here we design catalytic antimicrobial robots (CARs) that precisely and controllably kill, degrade and remove biofilms with remarkable efficiency. CARs exploit iron oxide nanoparticles (NPs) with dual catalytic-magnetic functionality that (i) generate bactericidal free radicals, (ii) breakdown the biofilm exopolysaccharide (EPS) matrix, and (iii) remove the fragmented biofilm debris via magnetic field driven robotic assemblies. We develop two distinct CAR platforms. The first platform, the biohybrid CAR, is formed from NPs and biofilm degradation products. After catalytic bacterial killing and EPS disruption, magnetic field gradients assemble NPs and the biodegraded products into a plow-like superstructure. When driven with an external magnetic field, the biohybrid CAR completely removes biomass in a controlled manner, preventing biofilm regrowth. Biohybrid CARs can be swept over broad swathes of surface or can be moved over well-defined paths for localized removal with microscale precision. The second platform, the 3D molded CAR, is a polymeric soft robot with embedded catalytic-magnetic NPs, formed in a customized 3D printed mold to perform specific tasks in enclosed domains. Vane-shaped CARs remove biofilms from curved walls of cylindrical tubes, and helicoid-shaped CARs drill through biofilm clogs, while simultaneously killing bacteria. In addition, we demonstrate applications of CARs to target highly confined anatomical surfaces in the interior of human teeth. These 'kill-degrade-and-remove' CARs systems could have significant impact in fighting persistent biofilm-infections and in mitigating biofouling of medical devices and diverse surfaces.},
}
@article {pmid31531109,
year = {2019},
author = {Veloz, JJ and Alvear, M and Salazar, LA},
title = {Evaluation of Alternative Methods to Assess the Biological Properties of Propolis on Metabolic Activity and Biofilm Formation in Streptococcus mutans.},
journal = {Evidence-based complementary and alternative medicine : eCAM},
volume = {2019},
number = {},
pages = {1524195},
doi = {10.1155/2019/1524195},
pmid = {31531109},
issn = {1741-427X},
abstract = {Several biological activities have been reported for the Chilean propolis, among their antimicrobial and antibiofilm properties, due to its high polyphenol content. In this study, we evaluate alternative methods to assess the effect of Chilean propolis on biofilm formation and metabolic activity of Streptococcus mutans (S. mutans), a major cariogenic agent in oral cavity. Biofilm formation was studied by using crystal violet and by confocal microscopy. The metabolic activity of biofilm was evaluated by MTT and by flow cytometry analysis. The results show that propolis reduces biofilm formation and biofilm metabolic activity in S. mutans. When the variability of the methods to measure biofilm formation was compared, the coefficient of variation (CV) fluctuated between 12.8 and 23.1% when using crystal violet methodology. On the other hand, the CV ranged between 2.2 and 3.3% with confocal microscopy analysis. The CV for biofilm's metabolic activity measured by MTT methodology ranged between 5.0 and 11.6%, in comparison with 1.9 to 3.2% when flow cytometry analysis was used. Besides, it is possible to conclude that the methods based on colored compounds presented lower precision to study the effect of propolis on biofilm properties. Therefore, we recommend the use of flow cytometry and confocal microscopy in S. mutans biofilm analysis.},
}
@article {pmid31530887,
year = {2019},
author = {Marbach, H and Mayer, K and Vogl, C and Lee, JYH and Monk, IR and Sordelli, DO and Buzzola, FR and Ehling-Schulz, M and Grunert, T},
title = {Within-host evolution of bovine Staphylococcus aureus selects for a SigB-deficient pathotype characterized by reduced virulence but enhanced proteolytic activity and biofilm formation.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {13479},
doi = {10.1038/s41598-019-49981-6},
pmid = {31530887},
issn = {2045-2322},
support = {FWF-P29304-B22//Austrian Science Fund (Fonds zur F&amp;#x00F6;rderung der Wissenschaftlichen Forschung)/ ; PP14311265//Veterin&amp;#x00E4;rmedizinische Universit&amp;#x00E4;t Wien (University of Veterinary Medicine, Vienna)/ ; },
abstract = {Staphylococcus aureus is a major cause of bovine mastitis, commonly leading to long-lasting, persistent and recurrent infections. Thereby, S. aureus constantly refines and permanently adapts to the bovine udder environment. In this work, we followed S. aureus within-host adaptation over the course of three months in a naturally infected dairy cattle with chronic, subclinical mastitis. Whole genome sequence analysis revealed a complete replacement of the initial predominant variant by another isogenic variant. We report for the first time within-host evolution towards a sigma factor SigB-deficient pathotype in S. aureus bovine mastitis, associated with a single nucleotide polymorphism in rsbU (G368A → G122D), a contributor to SigB-functionality. The emerged SigB-deficient pathotype exhibits a substantial shift to new phenotypic traits comprising strong proteolytic activity and poly-N-acetylglucosamine (PNAG)-based biofilm production. This possibly unlocks new nutritional resources and promotes immune evasion, presumably facilitating extracellular persistence within the host. Moreover, we observed an adaptation towards attenuated virulence using a mouse infection model. This study extends the role of sigma factor SigB in S. aureus pathogenesis, so far described to be required for intracellular persistence during chronic infections. Our findings suggest that S. aureus SigB-deficiency is an alternative mechanism for persistence and underpin the clinical relevance of staphylococcal SigB-deficient variants which are consistently isolated during human chronic infections.},
}
@article {pmid31529027,
year = {2019},
author = {Bjarnsholt, T and Østrup Jensen, P and Alhede, M},
title = {Revival of Krebs-Ringer balanced salt solution for the investigation of polymorphonuclear leukocytes and Pseudomonas aeruginosa biofilm interaction.},
journal = {Pathogens and disease},
volume = {},
number = {},
pages = {},
doi = {10.1093/femspd/ftz052},
pmid = {31529027},
issn = {2049-632X},
abstract = {To study the interaction between aggregating bacteria and polymorphonuclear leukocytes (PMNs) in vitro the chosen medium must favor both the isolated PMNs and the bacteria. To investigate the best-suited medium for the in vitro survival of isolated unactivated human PMNs, we compared three different mammalian cell media: Krebs-Ringer balanced salt solution (BSS), Hanks' BSS (HBSS) and Roswell Park Memorial Institute (RPMI) 1640. The death of PMNs was estimated as the release of lactate dehydrogenase activity. Furthermore, two types of serum, human (HS) and fetal bovine (FBS), were compared at different concentrations (0%, 2%, 5%, 10%) and at three different time points (2, 4, 20 h). We show that Krebs-Ringer BSS prolonged the survival of PMNs compared to HBSS and RPMI1640 and that the addition of 10% FBS significantly enhanced long-term survival (20 h) compared to HS. Furthermore, we observed aggregation of Pseudomonas aeruginosa when grown in the presence of either a mixture of histones, histone H3, arginine or lysine. In this study, we show that the use of Krebs-Ringer BSS is highly relevant for the study of the interaction of bacteria and PMNs in relation to novel treatment strategies of biofilm infections due to the reproduction of bacterial aggregation as seen in chronic bacterial infections.},
}
@article {pmid31528252,
year = {2019},
author = {Song, YG and Lee, SH},
title = {Efficacy of newly developed denture cleaning device on physical properties of denture material and Candida biofilm.},
journal = {Journal of dental sciences},
volume = {14},
number = {3},
pages = {248-254},
doi = {10.1016/j.jds.2019.01.011},
pmid = {31528252},
issn = {2213-8862},
abstract = {Background/purpose: Electrolyzed water has antimicrobial activity against oral microbes. The purpose of this study was to investigate the effects of a denture cleaning device that uses electrolyzed water on Candida biofilm on denture base-material and the physical properties of the denture material.<br><br>Materials and methods: Denture base-resin disks were prepared with Polymethyl methacrylate. After the formation of Candida albicans biofilm on the resin disks, the antimicrobial activity of the denture cleaning device and the chemical cleanser against C. albicans biofilm was compared. The resin disks were also treated with the cleaning device and the chemical cleanser for 150 days, and the physical properties were analyzed by an atomic force microscope, Vickers hardness tester, and colorimeter.<br><br>Results: The denture cleaning device and the chemical cleanser reduced the levels of C. albicans biofilm on the denture resin. Upon immersing of the resin disks for 150 days, the electrolyzed water of the denture cleaning device did not significantly change the surface roughness of the specimens, but significantly reduced its Vickers hardness compared to the initial value. The color changes of the resin disk were 0.477 ± 0.076, 0.612 ± 0.095 and 0.562 ± 0.096 after treating with tap water, the chemical cleanser, and the denture cleaning device, respectively.<br><br>Conclusion: The denture cleaning device may be suitable for use by the elderly to clean dentures without side effects caused by the misuse of chemical cleanser.},
}
@article {pmid31528123,
year = {2019},
author = {Thieme, L and Hartung, A and Tramm, K and Klinger-Strobel, M and Jandt, KD and Makarewicz, O and Pletz, MW},
title = {MBEC Versus MBIC: the Lack of Differentiation between Biofilm Reducing and Inhibitory Effects as a Current Problem in Biofilm Methodology.},
journal = {Biological procedures online},
volume = {21},
number = {},
pages = {18},
doi = {10.1186/s12575-019-0106-0},
pmid = {31528123},
issn = {1480-9222},
abstract = {Background: Biofilms are communities of aggregated, matrix-embedded microbial cells showing a high tolerance to an in principle adequate antibiotic therapy, often resulting in treatment failure. A major challenge in the management of biofilm-associated infections is the development of adequate, standardized biofilm susceptibility testing assays that are clinically meaningful, i.e. that their results correlate with treatment outcome. Different biofilm susceptibility endpoint parameters like the minimal biofilm eradication concentration (MBEC) or the minimal biofilm inhibitory concentration (MBIC) have been suggested as a guide for treatment of biofilm-associated infections, however with inconsistent perception and use among biofilm researchers, leading to confusion and contradictions among different anti-biofilm component studies and clinical trials.<br><br>Findings: Evaluation of anti-biofilm effects is mostly based on the untreated reference growth control biofilm measured at the same endpoint as the treated biofilm, neglecting the possible change of the untreated reference biofilm from the time point of pre-antimicrobial exposure to the measured endpoint. In this commentary, we point out the importance of individual quantification of mature, established biofilms before antimicrobial treatment for each biofilm model in order to draw conclusions on the measured biofilm effect size, i.e. biofilm reducing (MBEC) or biofilm inhibitory (MBIC) effects.<br><br>Conclusion: The assessment of pre-treatment biofilms contributes to a standardized use of biofilm susceptibility endpoint parameters, which is urgently needed to improve the clinical validity of future anti-biofilm assays.},
}
@article {pmid31527127,
year = {2019},
author = {Sultan, AR and Hoppenbrouwers, T and Lemmens-den Toom, NA and Snijders, SV and van Neck, JW and Verbon, A and de Maat, MPM and van Wamel, WJB},
title = {During the Early Stages of Staphylococcus aureus Biofilm Formation, induced Neutrophil Extracellular Traps (NETs) are degraded by Autologous Thermonuclease.},
journal = {Infection and immunity},
volume = {},
number = {},
pages = {},
doi = {10.1128/IAI.00605-19},
pmid = {31527127},
issn = {1098-5522},
abstract = {Staphylococcus aureus extracellular DNA (eDNA) plays a crucial role in the structural stability of biofilms during bacterial colonization, on the contrary, host immune responses can be induced by bacterial eDNA. Previously we observed production of S. aureus thermonuclease during the early stages of biofilm formation in a mammalian cell culture medium. Using a fluorescence resonance energy transfer (FRET)-based assay, we detected thermonuclease activity of S. aureus biofilms grown in Iscove's modified Dulbecco's medium (IMDM) earlier compared to widely-studied tryptic soy broth (TSB) grown biofilms. The thermonuclease found was Nuc1, confirmed by mass spectrometry and competitive Luminex assay. These results indicate that biofilm development in IMDM may not rely on eDNA for structural stability. A bacterial viability assay in combination with wheat germ agglutinin (WGA) staining confirmed the accumulation of dead cells and eDNA in biofilms grown in TSB. However, in IMDM-grown biofilms minimal amounts of eDNA were found and instead, polysaccharide intercellular adhesin (PIA) was detected. To investigate if this early production of thermonuclease plays a role in immune modulation by biofilm, we studied the effect of thermonuclease on human neutrophil extracellular traps (NETs) formation using a nuc knockout and complemented strain. We confirmed that thermonuclease produced by early stages biofilms grown in IMDM degraded biofilm-induced NETs. Additionally, neither the presence of biofilms nor thermonuclease stimulated an increase in reactive oxygen species (ROS) production by neutrophils. Our findings indicated that S. aureus, during the early stages of biofilm formation, actively evades the host immune responses by producing thermonuclease.},
}
@article {pmid31525949,
year = {2019},
author = {Wang, ZH and Liu, JM and Li, CY and Wang, D and Lv, H and Lv, SW and Zhao, N and Ma, H and Wang, S},
title = {Bacterial Biofilm Bioinspired Persistent Luminescence Nanoparticles with Gut-Oriented Drug Delivery for Colorectal Cancer Imaging and Chemotherapy.},
journal = {ACS applied materials &amp; interfaces},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsami.9b12853},
pmid = {31525949},
issn = {1944-8252},
abstract = {Colorectal cancer (CRC) now comes to be one of the leading causes of cancer incidence and mortality. Although nanomaterial-based drug delivery has been used for the treatment of colorectal cancer, inferior targeting ability of existing nanocarriers leads to inefficient treatment and side effects. Moreover, the majority of intravenously administered nanomaterials aggregate into the reticuloendothelial system, leaving certain hidden risk to human health. All those problems gave great demands for further construction of well-performed and biocompatible nanomaterials for in vivo theranostics. In the present work, from a biomimetic point of view, Lactobacillus reuteri biofilm (LRM) was coated on the surface of trackable zinc gallogermanate (ZGGO) near-infrared persistent luminescence mesoporous silica to create the bacteria bioinspired nanoparticles (ZGGO@SiO2@LRM), which hold the inherit capability of withstanding the digestion of gastric acid and targeted release 5-FU to colorectum. Through the background-free persistent luminescence bioimaging of ZGGO, the coating of LRM facilitated the localization of ZGGO@SiO2@LRM to the tumor area of colorectum for more than 24 h after intragastric administration. Furthermore, ZGGO@SiO2@LRM hardly entered the blood, which avoided possible damage to immune organs such as liver and spleen. In vivo chemotherapy experiment clearly demonstrated the number of tumors per mouse in ZGGO@SiO2@LRM group decreased by one-half compared with the 5-FU group (P < 0.001). To sum up, this LRM bioinspired nanoparticles could tolerate the digestion of gastric acid, aviod aggregation by the immune system, favor gut-oriented drug delivery, and targeted release oral 5-FU into colorectum for more than 24 h, which may give new application prospects for targeted delivery of oral drugs into the colorectum.},
}
@article {pmid31524581,
year = {2019},
author = {Brown, JL and Johnston, W and Delaney, C and Short, B and Butcher, MC and Young, T and Butcher, J and Riggio, M and Culshaw, S and Ramage, G},
title = {Polymicrobial oral biofilm models: simplifying the complex.},
journal = {Journal of medical microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1099/jmm.0.001063},
pmid = {31524581},
issn = {1473-5644},
abstract = {Over the past century, numerous studies have used oral biofilm models to investigate growth kinetics, biofilm formation, structure and composition, antimicrobial susceptibility and host-pathogen interactions. In vivo animal models provide useful models of some oral diseases; however, these are expensive and carry vast ethical implications. Oral biofilms grown or maintained in vitro offer a useful platform for certain studies and have the advantages of being inexpensive to establish and easy to reproduce and manipulate. In addition, a wide range of variables can be monitored and adjusted to mimic the dynamic environmental changes at different sites in the oral cavity, such as pH, temperature, salivary and gingival crevicular fluid flow rates, or microbial composition. This review provides a detailed insight for early-career oral science researchers into how the biofilm models used in oral research have progressed and improved over the years, their advantages and disadvantages, and how such systems have contributed to our current understanding of oral disease pathogenesis and aetiology.},
}
@article {pmid31523511,
year = {2019},
author = {Pelyuntha, W and Chaiyasut, C and Kantachote, D and Sirilun, S},
title = {Cell-free supernatants from cultures of lactic acid bacteria isolated from fermented grape as biocontrol against Salmonella Typhi and Salmonella Typhimurium virulence via autoinducer-2 and biofilm interference.},
journal = {PeerJ},
volume = {7},
number = {},
pages = {e7555},
doi = {10.7717/peerj.7555},
pmid = {31523511},
issn = {2167-8359},
abstract = {Background: Salmonella Typhi and Salmonella Typhimurium are the causative pathogens of salmonellosis, and they are mostly found in animal source foods (ASF). The inappropriate use of antibiotics enhances the possibility for the emergence of antibiotic resistance in pathogens and antibiotic residue in ASF. One promising alternative to antibiotics in animal farming is the use of lactic acid bacteria (LAB).<br><br>Methods: The present study was carried out the cells and/or the cell-free culture supernatants (CFCS) from beneficial LAB against S. Typhi and S. Typhimurium. The antibacterial mechanisms of LAB-CFCS as biocontrol agents against both Salmonella serovars were investigated through the analysis of anti-salmonella growth activity, biofilm inhibition and quorum quenching activity.<br><br>Results: Among 146 LAB strains isolated from 110 fermented food samples, the 2 strong inhibitory effect strains (WM33 and WM36) from fermented grapes against both Salmonella serovars were selected. Out of the selected strains, WM36 was the most effective inhibitor, which indicated S. Typhi by showing 95.68% biofilm inhibition at 20% biofilm inhibition concentration (BIC) and reduced 99.84% of AI-2 signaling interference. The WM33 was the best to control S. Typhimurium by producing 66.46% biofilm inhibition at only 15% BIC and 99.99% AI-2 signaling a reduction. The 16S rDNA was amplified by a polymerase chain reaction (PCR). The selected isolates were identified as Weissella viridescens WM33 and Weissella confusa WM36 based on nucleotide homology and phylogenetic analysis.<br><br>Conclusion: The metabolic extracts from Weissella spp. inhibit Salmonella serovars with the potential to be used as biocontrol agents to improve microbiological safety in the production of ASF.},
}
@article {pmid31523409,
year = {2019},
author = {Saidi, N and Owlia, P and Marashi, SMA and Saderi, H},
title = {Inhibitory effect of probiotic yeast Saccharomyces cerevisiae on biofilm formation and expression of α-hemolysin and enterotoxin A genes of Staphylococcus aureus.},
journal = {Iranian journal of microbiology},
volume = {11},
number = {3},
pages = {246-254},
pmid = {31523409},
issn = {2008-3289},
abstract = {Background and Objectives: Staphylococcus aureus, as an opportunistic pathogen, is the cause of a variety of diseases from mild skin infections to severe invasive infections and food poisoning. Increasing antibiotic resistance in S. aureus isolates has become a major threat to public health. The use of compounds produced by probiotics can be a solution to this problem. Thus, the purpose of this study was to investigate the effect of Saccharomyces cerevisiae on some virulence factors (biofilm, α-hemolysin, and enterotoxin A) of S. aureus.<br><br>Materials and Methods: Supernatant and lysate extracts were prepared from S. cerevisiae S3 culture. Sub-MIC concentrations of both extracts were separately applied to S. aureus ATCC 29213 (methicillin-sensitive S. aureus; MSSA) and S. aureus ATCC 33591 (methicillin-resistant S. aureus; MRSA) strains. Biofilm formation of these strains was measured by microtiter plate assay and expression level of α-hemolysin and enterotoxin A genes (hla and sea, respectively) using real-time PCR technique.<br><br>Results: The supernatant extract has reduced both biofilm formation and expression of sea and hla genes, while lysate extract had only anti-biofilm effects. The MRSA strain showed more susceptibility to yeast extracts than MSSA strain in all tests.<br><br>Conclusion: The present study exhibited favorable antagonistic effects of S. cerevisiae S3, as a probiotic yeast, on MSSA and MRSA strains. Based on the findings of this study, the compounds produced by this yeast can be used to control S. aureus infections; however, further similar studies should be conducted to confirm the findings of the present study.},
}
@article {pmid31523169,
year = {2019},
author = {Liu, J and Cai, M and Yan, H and Fu, J and Wu, G and Zhao, Z and Zhao, Y and Wang, Y and Sun, Y and You, Y and Lin, L and Huang, J and Huang, R and Zeng, J},
title = {Yunnan Baiyao reduces hospital-acquired pressure ulcers via suppressing virulence gene expression and biofilm formation of Staphylococcus aureus.},
journal = {International journal of medical sciences},
volume = {16},
number = {8},
pages = {1078-1088},
doi = {10.7150/ijms.33723},
pmid = {31523169},
issn = {1449-1907},
abstract = {Yunnan Baiyao (YB) as a kind of famous Chinese herbal medicine, possessed hemostatic, invigorating the circulation of blood, and anti-inflammatory effects. Identifying strategies to protect patients at risk for hospital-acquired pressure ulcers (HAPU) is essential. Herein, our results showed that YB treatment can effectively reduce the acne wound area and improve efficacy in a comparative study of 60 cases HAPU patients with S. aureus positive of acne wound pathogens. Furthermore, YB inhibited HIa expression and suppressed accessory gene regulator (agr) system controlled by regulatory RNA II and RNA III molecule using pALC1740, pALC1742 and pALC1743 S. aureus strain linked to gfpuvr reporter gene. Moreover, YB downregulated cao mRNA expression and inhibited coagulase activity by RT-PCR, slide and tube coagulase test. Additionally, YB downregulated seb, sec, sed, and tsst-1 mRNA expression to suppress enterotoxin and tsst-1 secretion and adhesion function related genes sarA, icaA, and cidA mRNA expression. Taken together, the data suggest that YB may reduce HAPU via suppressing virulence gene expression and biofilm formation of S. aureus.},
}
@article {pmid31521779,
year = {2019},
author = {Alfa, MJ and Singh, H},
title = {Impact of wet storage and other factors on biofilm formation and contamination of patient-ready endoscopes: a narrative review.},
journal = {Gastrointestinal endoscopy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.gie.2019.08.043},
pmid = {31521779},
issn = {1097-6779},
abstract = {The 2019 Food and Drug Administration report indicates that the clinical studies undertaken by the 3 main GI endoscope manufacturers demonstrate 5.4% of patient-ready duodenoscopes remain culture positive for high-concern organisms. The root causes of this persistent contamination are poorly understood. The objectives of this review include summarizing (1) the impact of inadequate manual cleaning, and inadequate drying during storage on the formation of build-up biofilm in endoscope channels, (2) the impact of de-foaming agents used during patient procedures on drying efficacy, (3) the data showing the importance of build-up biofilm on persistent microbial survival, and (4) potential impact of implementation of a Quality Systems approach in GI endoscopy reprocessing.},
}
@article {pmid31521732,
year = {2019},
author = {Horiuchi, A and Kokubu, E and Warita, T and Ishihara, K},
title = {Synergistic biofilm formation by Parvimonas micra and Fusobacterium nucleatum.},
journal = {Anaerobe},
volume = {},
number = {},
pages = {102100},
doi = {10.1016/j.anaerobe.2019.102100},
pmid = {31521732},
issn = {1095-8274},
abstract = {Parvimonas micra is frequently isolated from lesions of apical periodontitis and is a major disease-related pathogen. One of the main causes of apical periodontitis is extraradicular biofilm. In this study, we investigated polymicrobial biofilm formation by P. micra and species associated with apical periodontitis. The coaggregation activity of P. micra with partner strains was investigated by visual assays. Synergistic biofilm formation was evaluated by cocultures of P. micra and partner strains. Growth of planktonic cells was measured by evaluating the absorbance at OD660, and biofilm formation was examined by staining with crystal violet. The effects of soluble components on synergistic biofilm formation and planktonic cell growth were examined after coculture of P. micra and other strains separated with a 0.4-μm pore-size porous membrane. P. micra coaggregated with Fusobacterium nucleatum, Porphyromonas gingivalis, or Capnoctyophaga ochracea. P. micra showed no coaggregation with Staphylococcus aureus, S. epidermidis, or Prevotella intermedia. In mixed cultures, biofilm formation by P. micra and F. nucleatum was greater than that by P. micra and P. gingivalis or C. ochracea. In separated cocultures, planktonic cell growth of P. micra was enhanced by each of the three species. Biofilm formation by P. micra was enhanced by F. nucleatum and C. ochracea; however, no significant enhancement was observed with P. gingivalis. These data indicated that P. micra and F. nucleatum had synergistic effects in biofilm formation and that these effects may be important for colonization by these two species in apical periodontitis lesions.},
}
@article {pmid31520957,
year = {2019},
author = {Cheng, H and Cheng, D and Mao, J and Lu, T and Hong, PY},
title = {Identification and characterization of core sludge and biofilm microbiota in anaerobic membrane bioreactors.},
journal = {Environment international},
volume = {133},
number = {Pt A},
pages = {105165},
doi = {10.1016/j.envint.2019.105165},
pmid = {31520957},
issn = {1873-6750},
abstract = {An analysis of sludge (i.e., 63 samples) and biofilm (i.e., 79 samples) sampled from 13 anaerobic membrane bioreactors (AnMBR) was conducted. Predominant microbial community identification and multivariate analysis indicate that these reactors showed different microbial community structure, but these differences had no impact on the overall AnMBR performance. Instead, core microbial genera which occurred in ≥90% of sludge (20 genera) and biofilm (12 genera) samples could potentially account for the AnMBR performance. A further calculation on net growth rate (NGR) of core genera in sludge suggested distribution into two main groups (i.e., I: low relative abundance and NGR, II: high relative abundance or high NGR). Consistent positive correlations between bacterial genera were observed among those that exhibited either high relative abundance or high NGR. The anaerobic microbial consortium in both sludge and biofilm were largely affected by stochastic dispersal and migration processes (i.e., neutral assembly). However, Acinetobacter spp. and Methanobacterium spp. occurred consistently in higher frequency in the biofilm but in lower occurrence frequency in the AnMBR permeate. Findings from this study suggest first, specific core microorganisms exist in the sludge regardless of the operating conditions of the AnMBRs, and second, prevention of biofoulant layer on anaerobic membranes can be devised by minimizing attachment of microbes on surfaces in a non-selective manner.},
}
@article {pmid31520885,
year = {2019},
author = {Yuan, Z and Tao, B and He, Y and Mu, C and Liu, G and Zhang, J and Liao, Q and Liu, P and Cai, K},
title = {Remote eradication of biofilm on titanium implant via near-infrared light triggered photothermal/photodynamic therapy strategy.},
journal = {Biomaterials},
volume = {223},
number = {},
pages = {119479},
doi = {10.1016/j.biomaterials.2019.119479},
pmid = {31520885},
issn = {1878-5905},
abstract = {Biofilm formation is a main challenge in treatment of bone-implant-associated infections, resulting in tolerance to immune system and antibiotics. However, smart non-surgical or non-invasive treatment methods of combating established biofilm on an implant have been less reported. Herein, a therapeutic system consisting of mesoporous polydopamine nanoparticles (MPDA) to combat biofilm is reported for the first time. We develop a synergistic photothermal/photodynamic therapy (PTT/PDT) strategy aiming for biofilms eradication on titanium (Ti) implant, which is integrated with MPDA loading with photosensitizer Indocyanine Green (ICG) by π-π stacking. Specifically, MPDA is functionalized with RGD peptide to endow the modified Ti sample (Ti-M/I/RGD) with good cytocompatibility. More importantly, Ti-M/I/RGD implant remarkably kills Staphylococcus aureus (S. aureus) biofilm with an efficiency of 95.4% in vivo upon near infrared (NIR). After biofilm eradication, implant still displays great performance regarding osteogenesis and osseointegration. Overall, this study provides a PTT/PDT strtategy for the development of antibacterial Ti implants for potential orthpediac application.},
}
@article {pmid31519064,
year = {2019},
author = {Widiasih Widiyanto, T and Chen, X and Iwatani, S and Chibana, H and Kajiwara, S},
title = {Role of MFS transporter Qdr2p in biofilm formation by Candida glabrata.},
journal = {Mycoses},
volume = {},
number = {},
pages = {},
doi = {10.1111/myc.13005},
pmid = {31519064},
issn = {1439-0507},
abstract = {BACKGROUND: Candida glabrata represents the second-most frequent cause of candidiasis infections of the mucosa, bloodstream, and genito-urinary tract in immunocompromised individuals. The incidence of C. glabrata infection has increased significantly in the last two decades, mainly due to this species' abilities to resist various antifungal drugs and to form biofilms.<br><br>OBJECTIVES: We focused on the relationship between biofilm formation and the product of QDR2, a C. glabrata member of the Major Facilitator Superfamily (MFS) gene family, given that fungal biofilm formation limits drug penetration and is associated with persistent infection.<br><br>METHODS: The fungal cells in biofilms were compared between a C. glabrata ∆qdr2 mutant and its wild-type strain. Cells were analyzed for metabolism activity and drug susceptibility (using tetrazolium assay), adhesion activity, growth assay, and intracellular pH (using flow cytometry).<br><br>RESULTS: Compared to the wild-type, the C. glabrata ∆qdr2 showed lower adhesion activity and higher fluconazole susceptibility when assessed as a biofilm. The mutant also showed decreased metabolic activity during biofilm formation. Furthermore, the mutant grew more slowly under neutral-basic pH conditions. The qdr2 deletion in C. glabrata resulted in an impaired ability to maintain pH homeostasis, which led in turn to a reduction of cell growth and of adherence to an artificial matrix.<br><br>CONCLUSION: These results suggested that the Qdr2p function is needed for proper biofilm formation and biofilm maintenance in C. glabrata as well as biofilm drug resistance towards fluconazole. Qdr2p may play an important role in C. glabrata's ability to form biofilms on implanted medical devices in human bodies.},
}
@article {pmid31518800,
year = {2019},
author = {Iannacone, F and Di Capua, F and Granata, F and Gargano, R and Pirozzi, F and Esposito, G},
title = {Effect of carbon-to-nitrogen ratio on simultaneous nitrification denitrification and phosphorus removal in a microaerobic moving bed biofilm reactor.},
journal = {Journal of environmental management},
volume = {250},
number = {},
pages = {109518},
doi = {10.1016/j.jenvman.2019.109518},
pmid = {31518800},
issn = {1095-8630},
abstract = {In this study, long-term simultaneous nitrification denitrification (SND) and phosphorous removal were investigated in a continuous-flow microaerobic MBBR (mMBBR) operated at a dissolved oxygen (DO) concentration of 1.0 (±0.2) mg L-1. The mMBBR performance was evaluated at different feed carbon-to-nitrogen (C/N) ratios (2.7, 4.2 and 5.6) and HRTs (2 days and 1 day). Stable long-term mMBBR operation and chemical oxygen demand (COD), total inorganic nitrogen (TIN) and phosphorous (P-PO43-) removal efficiencies up to 100%, 68% and 72%, respectively, were observed at a feed C/N ratio of 4.2. Lower TIN removal efficiency and unstable performance were observed at feed C/N ratios of 2.7 and 5.6, respectively. HRT decrease from 2 days to 1 day resulted in transient NH4+ accumulation and higher NO2-/NO3- ratio in the effluent. Batch activity tests showed that biofilm cultivation at a feed C/N ratio of 4.2 resulted in the highest denitrifying activity (189 mg N gVSS-1 d-1), whereas the highest nitrifying activity (316 mg N gVSS-1 d-1) was observed after cultivation at a feed C/N ratio of 2.7. Thermodynamic modeling with Visual MINTEQ and stoichiometric evaluations revealed that P removal was mainly biological and can be attributed to the P-accumulating capacity of denitrifying bacteria.},
}
@article {pmid31518447,
year = {2019},
author = {Kettles, RA and Tschowri, N and Lyons, KJ and Sharma, P and Hengge, R and Webber, MA and Grainger, DC},
title = {The Escherichia coli MarA protein regulates the ycgZ-ymgABC operon to inhibit biofilm formation.},
journal = {Molecular microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/mmi.14386},
pmid = {31518447},
issn = {1365-2958},
abstract = {The Escherichia coli marRAB operon is a paradigm for chromosomally encoded antibiotic resistance. The operon exerts its effect via an encoded transcription factor called MarA that modulates efflux pump and porin expression. In this work we show that MarA is also a regulator of biofilm formation. Control is mediated by binding of MarA to the intergenic region upstream of the ycgZ-ymgABC operon. The operon, known to influence the formation of curli fibres and colanic acid, is usually expressed during periods of starvation. Hence, the ycgZ-ymgABC promoter is recognised by σ38 (RpoS) associated RNA polymerase. We show that MarA does not influence σ38 dependent transcription. Instead, MarA drives transcription by the housekeeping σ70 associated RNA polymerase. The effects of MarA on ycgZ-ymgABC expression are coupled to biofilm formation by the rcsCDB phosphorelay system, with YcgZ, YmgA and YmgB forming a complex that directly interacts with the histidine kinase domain of RcsC.},
}
@article {pmid31516325,
year = {2019},
author = {Farrag, HA and Hosny, AEMS and Hawas, AM and Hagras, SAA and Helmy, OM},
title = {Potential efficacy of garlic lock therapy in combating biofilm and catheter-associated infections; experimental studies on an animal model with focus on toxicological aspects.},
journal = {Saudi pharmaceutical journal : SPJ : the official publication of the Saudi Pharmaceutical Society},
volume = {27},
number = {6},
pages = {830-840},
doi = {10.1016/j.jsps.2019.05.004},
pmid = {31516325},
issn = {1319-0164},
abstract = {Background: Life-threatening central venous catheter-related infections are primarily initiated by biofilm formation on the catheter surface. Antibiotic lock therapy is recommended for eradicating intraluminal biofilm. In the era of antibiotic resistance, antibiotics of natural origins provide an effective and cheap option for combating resistant strains. Garlic especially stole the spotlight because of its impressive antimicrobial effectiveness against such superbugs.<br><br>Aim: Is to estimate the potential use of fresh garlic extract (FGE) as a lock agent against multi-drug resistant (MDR) bacteria.<br><br>Methods: The agar well diffusion and broth microdilution techniques were employed to test the antimicrobial activities of FGE against five MDR strains; E. coli, Pseudomonas aeruginosa (P. aeruginosa), Klebsiella pneumoniae (K. pneumoniae), Serratia marscens (S. marscens) and Methicillin-resistant Staphylococcus aureus (MRSA). Then the protective and therapeutic efficiencies of FGE against bacterial biofilms were in-vitro evaluated; at concentrations of 100, 75, 50 and 25%; in tissue culture plate (TCP) and on the polyurethane (PU) sheets using the crystal violet (CV) assay and colony-forming unit (CFU), respectively. Scanning electron microscopy (SEM) was also used to confirm eradication of biofilms on PU sheets. Finally, systemic and deep tissue infections by P. aeruginosa and MRSA were induced in mice that were then treated by FGE at either 100 or 200 mg/kg for seven days. Where the antibacterial activity was assessed by tissue and blood culturing at the end of the treatment period. Biochemical, hematological and histological parameters were also investigated.<br><br>Results: FGE exhibited potent in-vitro and in-vivo antibacterial and antibiofilm activities against MDR strains. It not only didn't exhibit toxicological effects at the hematological and the histological levels but also provided protective effects as demonstrated by the significant drop in the biochemical parameters.<br><br>Conclusion: FGE has the potential to be used as a prophylactic and/or therapeutic lock agent against biofilm-associated infections caused by MDR bacteria.},
}
@article {pmid31515923,
year = {2019},
author = {Røder, HL and Liu, W and Sørensen, SJ and Madsen, JS and Burmølle, M},
title = {Interspecies interactions reduce selection for a biofilm optimized variant in a four-species biofilm model.},
journal = {Environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1462-2920.14802},
pmid = {31515923},
issn = {1462-2920},
abstract = {Multispecies biofilms are structured and spatially defined communities, where interspecies interactions impact assembly and functionality. Here we compared the spatial organization and growth of bacterial cells in differently composed biofilm communities over time to determine links between interspecies interactions and selection for biofilm phenotypes of individual species. An established model community consisting of Stenotrophomonas rhizophila, Xanthomonas retroflexus, Microbacterium oxydans and Paenibacillus amylolyticus was used. It was found that interspecies interactions led to varying levels of selection for a new colony phenotype of X. retroflexus, depending on the presence/absence of other species. When M. oxydans was absent, X. retroflexus was not able to establish in the top layers of the biofilm, which led to selection for a hyper-matrix forming phenotype of X. retroflexus that successfully established in the biofilm top layers. No such phenotypic X. retroflexus variants were identified in the presence of M. oxydans. These findings indicate that interspecies interactions may lead to favourable localization of individual species in a multispecies biofilm and thereby reduce selection for competitive phenotypes. This article is protected by copyright. All rights reserved.},
}
@article {pmid31515192,
year = {2019},
author = {Kim, A and Jung, JH and Lee, YJ and Park, JW and Pyon, JK},
title = {Minimally invasive salvage of infected breast tissue expanders: A continuous closed irrigation technique based on surface biofilm disruption.},
journal = {Journal of plastic, reconstructive &amp; aesthetic surgery : JPRAS},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.bjps.2019.07.020},
pmid = {31515192},
issn = {1878-0539},
abstract = {BACKGROUND: Removal of the infected device has been the general treatment for device-associated infection in antibiotic failure. There have been anecdotal attempts to salvage infected medical devices by introducing a continuous closed irrigation system.<br><br>OBJECTIVE: This study examines whether continuous closed irrigation of an infected device is a successful alternative to removal in patients with recalcitrant device-associated infection.<br><br>METHODS: Patients who were diagnosed with recalcitrant periexpander infections during the course of expander-implant breast reconstruction from 2010 to 2018 were enrolled in a retrospective case-control study. Patients who failed antibiotics before 2017 underwent expander removal, but patients since 2017 underwent continuous closed irrigation of the infected expanders. Treatment details and clinical outcomes were compared. Rationale for expander irrigation was based on review of the current literature on biofilm research.<br><br>RESULTS: During the study period, 21 out of the 1176 patients were diagnosed with periexpander infection recalcitrant to antibiotic therapy. Among the 21 patients, 16 underwent expander removal and five underwent expander irrigation. Clinical outcomes were comparable in terms of resolution of infection signs. The irrigation group showed fewer patients who abandoned reconstruction after infection treatment (removal = 11/16, irrigation = 1/5). Literature review revealed that expander irrigation might have induced hydrodynamic disruption of the biofilm structure.<br><br>CONCLUSION: Expander irrigation was less invasive than removal and effective in suppressing severe recalcitrant periexpander infection. Continuous closed irrigation of infected expander devices may be a successful antibiofilm strategy in treating device-associated infections in select patients.},
}
@article {pmid31514534,
year = {2019},
author = {Braga, AS and Girotti, LD and de Melo Simas, LL and Pires, JG and Pelá, VT and Buzalaf, MAR and Magalhães, AC},
title = {Effect of commercial herbal toothpastes and mouth rinses on the prevention of enamel demineralization using a microcosm biofilm model.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-9},
doi = {10.1080/08927014.2019.1662897},
pmid = {31514534},
issn = {1029-2454},
abstract = {This work evaluated the effects of commercial toothpastes and mouth rinses containing natural/herbal agents on biofilm viability, extracellular polysaccharide (EPS) production and on enamel demineralization in vitro. Microcosm biofilm was produced on bovine enamel for 5 days and treated daily with: Orgânico natural® (toothpaste/mouth rinse), Boni Natural Menta &amp; Malaleuca® (toothpaste/mouth rinse), Propolis &amp; Myrrh® (toothpaste), Colgate Total 12 Clean Mint® (toothpaste, positive control), Malvatricin® Plus (mouth rinse), PerioGard® (mouth rinse, positive control) or PBS (negative control). Tom's Propolis &amp; Myrrh® and Colgate Total 12® toothpastes and Malvatricin® Plus and PerioGard® mouth rinses significantly reduced biofilm viability (p < 0.05). Only PerioGard® had significant effects on biofilm thickness and EPS. Despite the indication that Tom's Propolis &amp; Myrrh® significantly reduced lesion depth, only Colgate Total 12® significantly reduced mineral loss. Malvatricin® Plus significantly reduced mineral loss and lesion depth, as did PerioGard®. Some herbal products, Malvatricin® Plus and Tom's Propolis &amp; Myrrh®, showed anticaries effects.},
}
@article {pmid31514307,
year = {2019},
author = {Balázs, VL and Horváth, B and Kerekes, E and Ács, K and Kocsis, B and Varga, A and Böszörményi, A and Nagy, DU and Krisch, J and Széchenyi, A and Horváth, G},
title = {Anti-Haemophilus Activity of Selected Essential Oils Detected by TLC-Direct Bioautography and Biofilm Inhibition.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {18},
pages = {},
doi = {10.3390/molecules24183301},
pmid = {31514307},
issn = {1420-3049},
support = {NKFI 18 K 128217//NKFI (National Research, Development and Innovation Office)/ ; },
abstract = {Essential oils (EOs) are becoming increasingly popular in medical applications because of their antimicrobial effect. Direct bioautography (DB) combined with thin layer chromatography (TLC) is a screening method for the detection of antimicrobial compounds in plant extracts, for example, in EOs. Due to their lipophilic character, the common microbiological assays (etc. disk diffusion) could not provide reliable results. The aim of this study was the evaluation of antibacterial and anti-biofilm properties of the EO of cinnamon bark, clove, peppermint, thyme, and their main components against Haemophilus influenzae and H. parainfluenzae. Oil in water (O/W) type Pickering nano-emulsions stabilized with silica nanoparticles from each oil were prepared to increase their water-solubility. Samples with Tween80 surfactant and absolute ethanol were also used. Results showed that H. influenzae was more sensitive to the EOs than H. parainfluenzae (except for cinnamon bark oil). In thin layer chromatography-direct bioautography (TLC-DB) the ethanolic solutions of thyme oil presented the best activity against H. influenzae, while cinnamon oil was the most active against H. parainfluenzae. Pickering nano-emulsion of cinnamon oil inhibited the biofilm formation of H. parainfluenzae (76.35%) more efficiently than samples with Tween80 surfactant or absolute ethanol. In conclusion, Pickering nano-emulsion of EOs could inhibit the biofilm production effectively.},
}
@article {pmid31514119,
year = {2019},
author = {Zhang, Q and Yu, Z and Jin, S and Zhu, L and Liu, C and Zheng, H and Zhou, T and Liu, Y and Ruan, R},
title = {Lignocellulosic residue as bio-carrier for algal biofilm growth: Effects of carrier physicochemical proprieties and toxicity on algal biomass production and composition.},
journal = {Bioresource technology},
volume = {293},
number = {},
pages = {122091},
doi = {10.1016/j.biortech.2019.122091},
pmid = {31514119},
issn = {1873-2976},
abstract = {Five types of lignocellulosic materials were applied as the bio-carriers for low-cost algal biofilm cultivation of three algal strains. The effects of bio-carrier physicochemical properties and toxicity on algal cells growth and attachment were investigated. Rougher and hydrophilic bio-carrier could yield more algal biomass than smoother and hydrophobic bio-carrier. Pine sawdust (diameter: 0.420-0.595 mm) performed the best when cultured Diplosphaera sp. (9.61 g·m-2·day-1) biofilm. Meanwhile, bio-carriers could be leached by the culture medium during cultivation, and their energy conversion proprieties could be improved due to the reduced ash contents and the decreased crystallinities. In addition, Chlorella vulgaris growth tests indicated that pine sawdust (15.45%) leachate promoted cell growth, whereas rick husk (15.48%) and sugarcane bagasse (13.19%) leachate inhibited cell growth. And bio-carriers leachates also modified the chemical compositions (lipid, protein and carbohydrate) of algal cells and increased the corresponding saturated fatty acids methyl ester content (from 48.71 to 55.58-57.08%).},
}
@article {pmid31514099,
year = {2019},
author = {Wang, G and Liu, Y and Wu, M and Zong, W and Yi, X and Zhan, J and Liu, L and Zhou, H},
title = {Coupling the phenolic oxidation capacities of a bacterial consortium and in situ-generated manganese oxides in a moving bed biofilm reactor (MBBR).},
journal = {Water research},
volume = {166},
number = {},
pages = {115047},
doi = {10.1016/j.watres.2019.115047},
pmid = {31514099},
issn = {1879-2448},
abstract = {Phenolic wastewater containing phenol and 4-chlorophenol pose a risk to the environment and to human health. Treating them using chemical-biological coupling method is challenging. In this study, manganese oxidizing bacteria (MnOB) were enriched in moving bed biofilm reactor (MBBR) using synthetic phenol wastewater (800 mg L-1) to facilitate in situ production of biogenic manganese oxides (BioMnOx) after 90 days of operation. Then, 4-chlorophenol (4-CP) was added to the MBBR to simulate mixed phenolic wastewater. Comparing the MBBR (R1) without feeding Mn(II) and the MBBR with BioMnOx (R2) production, R2 exhibited robust phenol and 4-CP removal performance. 16S rRNA gene sequencing was employed to determine the microbial community. Subsequently, a batch experiment demonstrated that partly purified BioMnOx does not exhibits a capacity for phenol removal, but can efficiently remove 4-CP. Interestingly, 5-chloro-2-hydroxymuconic semialdehyde was found in the products of 4-CP degradation, which was the unique product of 4-CP degradation by catechol 2,3-dioxygenase (C23O). In both reactors, only catechol 1,2-dioxygenase (C12O) activity from microbes can be detected, indicating that the existence of BioMnOx provide an alternative pathway in addition to microbe driven 4-CP degradation. Overall, MBBR based MnOB enrichment under high phenol concentration was achieved, and 4-CP/phenol removal can be accelerated by in situ-formed BioMnOx. Considering the C23O-like activity of BioMnOx, our results suggest a new coupling strategy that involves nanomaterials and a microbial consortium.},
}
@article {pmid31513898,
year = {2019},
author = {Thiruvengadam, M and Venkidasamy, B and Karuppasamy, P and Subramanian, U},
title = {'Biofilm Clippers'- enzyme formulation for bovine mastitic biofilm therapy.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {103740},
doi = {10.1016/j.micpath.2019.103740},
pmid = {31513898},
issn = {1096-1208},
abstract = {Mastitis is one of the most important diseases that are threatening modern dairy farms. Biofilms of mastitic teat canal have serious clinical implications because of colonized pathogens having the ability to construct an extracellular polymeric substance (EPS) with increased tolerance to antimicrobials leads to difficulty in eradicating the infection. In this study, we investigated the synergistic biofilm disruptive effect of a combination of carbohydrate hydrolases targeting extracellular polysaccharides of biofilm matrix and we termed it as 'Biofilm Clippers (BC)'. Our findings demonstrate that the BC formulation exhibits intense biofilm-disrupting activity against Staphylococcus aureus biofilms. The results of the study showed that BC enables activity equivalent to physiologically achievable concentrations in disrupting biofilms of S. aureus in vitro. The synergistic anti-biofilm activities of BC on S. aureus biofilms demonstrated that the biofilm matrix is predominant of complex polysaccharides. Further, the confocal microscopic analysis demonstrates that the BC formulation is highly effective compared to the single treatment of either of the enzymes in disrupting the biofilm. To the best of our knowledge, this is the first report on the synergistic anti-biofilm activity of a class of enzyme formulation against mastitic biofilm mass. Even though a small study showed a promising effect on mastitic teat canal, further extensive investigation on a large number of bovines for mastitis therapeutic potential of this BC-derived product is now warranted.},
}
@article {pmid31513491,
year = {2019},
author = {Roes, C and Calladine, L and Morris, C},
title = {Biofilm management using monofilament fibre debridement technology: outcomes and clinician and patient satisfaction.},
journal = {Journal of wound care},
volume = {28},
number = {9},
pages = {608-622},
doi = {10.12968/jowc.2019.28.9.608},
pmid = {31513491},
issn = {0969-0700},
abstract = {OBJECTIVE: Best practice in wound bed preparation and biofilm-based wound management includes debridement to create a clean wound bed and to assist in minimising the redevelopment of biofilm. Biofilm that is not removed inhibits healing and redevelops if not prevented from doing so with topical antimicrobial agents. Monofilament fibre debriding technology (MFDT) is used for effective and rapid mechanical debridement of loose material, slough and biofilm. The objective of this evaluation was to determine the clinical effect and consequential levels of health professional and patient satisfaction with the results of a biofilm pathway that included MFDT to achieve debridement.<br><br>METHODS: This non-comparative, open label evaluation was conducted in static and non-static wounds that required debridement. MFDT was used to debride in a two-week evaluation of a biofilm pathway. Wounds were debrided three times in week one and twice in week two. Each debridement was followed by treatment with an antimicrobial dressing. Other care included secondary dressings and compression delivered according to local practice, guidelines and formularies. After the clinical evaluation, health professionals were invited to complete an online survey of the clinical outcomes and their satisfaction with the biofilm pathway.<br><br>RESULTS: There were 706 health professionals who provided answers to the survey questions. Wound types evaluated were leg ulcers (67.4%), pressure ulcers (10%), dehisced surgical wounds (1.7%), diabetic foot ulcers (7.4%) and other wounds (13.4%). Of the wounds, 9% were reported as non-static despite the eligibility criteria. Not all wounds followed the pathway. The most frequently-used antimicrobial was silver. Non-antimicrobial products used included all-in-one dressings, other secondary dressings and compression. There was a change in 77% of wounds overall after two weeks. Change was reported almost equally for both static and non-static wounds. Health professionals who did or did not follow the pathway were 'completely satisfied' or 'satisfied' with the overall clinical outcome 96% and 95%, respectively. Of the patients, 77% were 'completely satisfied' or 'satisfied' with healing after following the pathway, as reported by the treating health professional.<br><br>CONCLUSION: The biofilm pathway that includes MFDT appears effective. Wounds managed on the pathway were debrided effectively and healing progressed to the satisfaction of both health professionals and patients.},
}
@article {pmid31512521,
year = {2019},
author = {Jiang, X and Yan, X and Gu, S and Yang, Y and Zhao, L and He, X and Chen, H and Ge, J and Liu, D},
title = {Biosurfactants of Lactobacillus helveticus for biodiversity inhibit the biofilm formation of Staphylococcus aureus and cell invasion.},
journal = {Future microbiology},
volume = {14},
number = {},
pages = {1133-1146},
doi = {10.2217/fmb-2018-0354},
pmid = {31512521},
issn = {1746-0921},
abstract = {Aim: This study aimed to evaluate the differences of biosurfactants produced by two Lactobacillus helveticus strains against the biofilm formation of Staphylococcus aureus in vitro and in vivo. Materials &amp; methods: Scanning electron microscopy, Real time-quantitative PCR (RT-qPCR) and cell assay were used to analyze the inhibiting effect of biosurfactants against biofilm formation. Results &amp; conclusion: Results showed that the biosurfactants have anti-adhesive and inhibiting effects on biofilm formation in vivo and in vitro. The biofilm-formative genes and autoinducer-2 signaling regulated these characteristics, and the biosurfactant L. helveticus 27170 is better than that of 27058. Host cell adhesion and invasion results indicated that the biosurfactants L. helveticus prevented the S. aureus invading the host cell, which may be a new strategy to eliminate biofilms.},
}
@article {pmid31511592,
year = {2019},
author = {Lu, H and Que, Y and Wu, X and Guan, T and Guo, H},
title = {Metabolomics Deciphered Metabolic Reprogramming Required for Biofilm Formation.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {13160},
doi = {10.1038/s41598-019-49603-1},
pmid = {31511592},
issn = {2045-2322},
support = {2017YFC1308600, 2017YFC1308605//Ministry of Science and Technology of the People&amp;apos;s Republic of China (Chinese Ministry of Science and Technology)/ ; WF220441502//Shanghai Jiao Tong University (SJTU)/ ; 81274175, 31670031//National Natural Science Foundation of China (National Science Foundation of China)/ ; },
abstract = {Biofilm formation plays a key role in many bacteria causing infections, which mostly accounts for high-frequency infectious recurrence and antibiotics resistance. In this study, we sought to compare modified metabolism of biofilm and planktonic populations with UTI89, a predominant agent of urinary tract infection, by combining mass spectrometry based untargeted and targeted metabolomics methods, as well as cytological visualization, which enable us to identify the driven metabolites and associated metabolic pathways underlying biofilm formation. Surprisingly, our finding revealed distinct differences in both phenotypic morphology and metabolism between two patterns. Furthermore, we identified and characterized 38 differential metabolites and associated three metabolic pathways involving glycerolipid metabolism, amino acid metabolism and carbohydrate metabolism that were altered mostly during biofilm formation. This discovery in metabolic phenotyping permitted biofilm formation shall provide us a novel insight into the dissociation of biofilm, which enable to develop novel biofilm based treatments against pathogen causing infections, with lower antibiotic resistance.},
}
@article {pmid31510757,
year = {2019},
author = {Papadopoulou, D and Dabrowska, A and Harries, PG and Webb, JS and Allan, RN and Salib, RJ},
title = {Evaluation of a Bioengineered Honey and Its Synthetic Equivalent as Novel Staphylococcus aureus Biofilm-Targeted Topical Therapies in Chronic Rhinosinusitis.},
journal = {American journal of rhinology &amp; allergy},
volume = {},
number = {},
pages = {1945892419874700},
doi = {10.1177/1945892419874700},
pmid = {31510757},
issn = {1945-8932},
}
@article {pmid31508379,
year = {2019},
author = {Miao, X and Liu, H and Zheng, Y and Guo, D and Shi, C and Xu, Y and Xia, X},
title = {Inhibitory Effect of Thymoquinone on Listeria monocytogenes ATCC 19115 Biofilm Formation and Virulence Attributes Critical for Human Infection.},
journal = {Frontiers in cellular and infection microbiology},
volume = {9},
number = {},
pages = {304},
doi = {10.3389/fcimb.2019.00304},
pmid = {31508379},
issn = {2235-2988},
abstract = {This study aimed to determine the antimicrobial activity of thymoquinone (TQ) against Listeria monocytogenes, and to examine its inhibitory effects on biofilm formation, motility, hemolysin production, and attachment-invasion of host cells. The minimum inhibitory concentrations (MICs) of TQ against eight different L. monocytogenes strains ranged from 6.25-12.50 μg/mL. Crystal violet staining showed that TQ clearly reduced biofilm biomass at sub-MICs in a dose-dependent manner. Scanning electron microscopy suggested that TQ inhibited biofilm formation on glass slides and induced an apparent collapse of biofilm architecture. At sub-MICs, TQ effectively inhibited the motility of L. monocytogenes ATCC 19115, and significantly impacted adhesion to and invasion of human colon adenocarcinoma cells as well as the secretion of listeriolysin O. Supporting these findings, real-time quantitative polymerase chain reaction analysis revealed that TQ down-regulated the transcription of genes associated with motility, biofilm formation, hemolysin secretion, and attachment-invasion in host cells. Overall, these findings confirm that TQ has the potential to be used to combat L. monocytogenes infection.},
}
@article {pmid31508278,
year = {2019},
author = {Li, M and Li, L and Su, K and Liu, X and Zhang, T and Liang, Y and Jing, D and Yang, X and Zheng, D and Cui, Z and Li, Z and Zhu, S and Yeung, KWK and Zheng, Y and Wang, X and Wu, S},
title = {Highly Effective and Noninvasive Near-Infrared Eradication of a Staphylococcus aureus Biofilm on Implants by a Photoresponsive Coating within 20 Min.},
journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)},
volume = {6},
number = {17},
pages = {1900599},
doi = {10.1002/advs.201900599},
pmid = {31508278},
issn = {2198-3844},
abstract = {Biofilms have been related to the persistence of infections on medical implants, and these cannot be eradicated because of the resistance of biofilm structures. Therefore, a biocompatible phototherapeutic system is developed composed of MoS2, IR780 photosensitizer, and arginine-glycine-aspartic acid-cysteine (RGDC) to safely eradicate biofilms on titanium implants within 20 min. The magnetron-sputtered MoS2 film possesses excellent photothermal properties, and IR780 can produce reactive oxygen species (ROS) with the irradiation of near-infrared (NIR, λ = 700-1100 nm) light. Consequently, the combination of photothermal therapy (PTT) and photodynamic therapy (PDT), assisted by glutathione oxidation accelerated by NIR light, can provide synergistic and rapid killing of bacteria, i.e., 98.99 ± 0.42% eradication ratio against a Staphylococcus aureus biofilm in vivo within 20 min, which is much greater than that of PTT or PDT alone. With the assistance of ROS, the permeability of damaged bacterial membranes increases, and the damaged bacterial membranes become more sensitive to heat, thus accelerating the leakage of proteins from the bacteria. In addition, RGDC can provide excellent biosafety and osteoconductivity, which is confirmed by in vivo animal experiments.},
}
@article {pmid31507562,
year = {2019},
author = {Olsen, NMC and Røder, HL and Russel, J and Madsen, JS and Sørensen, SJ and Burmølle, M},
title = {Priority of Early Colonizers but No Effect on Cohabitants in a Synergistic Biofilm Community.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1949},
doi = {10.3389/fmicb.2019.01949},
pmid = {31507562},
issn = {1664-302X},
abstract = {The arrival order of different species to a habitat can strongly impact community assembly and succession dynamics, thus influencing functionality. In this study, we asked how prior colonization of one community member would influence the assembly of a synergistic multispecies biofilm community grown in vitro. We expected that the prior arrival would confer an advantage, in particular for good biofilm formers. Yet, we did not know if the cohabitants would be impaired or benefit from the pre-colonization of one member, depending on its ability to form biofilm. We used a consortium consisting of four soil bacteria; Stenotrophomonas rhizophila, Xanthomonas retroflexus, Microbacterium oxydans and Paenibacillus amylolyticus. This consortium has been shown to act synergistically when grown together, thus increasing biofilm production. The results showed that the two good biofilm formers gained a fitness advantage (increase in abundance) when allowed prior colonization on an abiotic surface before the arrival of their cohabitants. Interestingly, the significantly higher number of the pre-colonized biofilm formers did not affect the resulting composition in the subsequent biofilm after 24 h.},
}
@article {pmid31507548,
year = {2019},
author = {Bisht, K and Wakeman, CA},
title = {Discovery and Therapeutic Targeting of Differentiated Biofilm Subpopulations.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1908},
doi = {10.3389/fmicb.2019.01908},
pmid = {31507548},
issn = {1664-302X},
abstract = {The association of microorganisms into biofilms produces functionally organized microbial structures that promote community survival in a wide range of environments. Much like when individual cells within a multicellular organism express different genes from the same DNA blueprint, individual microbial cells located within different regions of a biofilm structure can exhibit distinct genetic programs. These spatially defined regions of physiologically differentiated cells are reminiscent of the role of tissues in multicellular organisms, with specific subpopulations in the microbial community serving defined roles to promote the overall health of the biofilm. The functions of these subpopulations are quite diverse and can range from dormant cells that can withstand antibiotic onslaughts to cells actively producing extracellular polymeric substances providing integrity to the entire community. The purpose of this review is to discuss the diverse roles of subpopulations in the stability and function of clonal biofilms, the methods for studying these subpopulations, and the ways these subpopulations can potentially be exploited for therapeutic intervention.},
}
@article {pmid31505984,
year = {2019},
author = {Lee, JH and Kim, YG and Raorane, CJ and Ryu, SY and Shim, JJ and Lee, J},
title = {The anti-biofilm and anti-virulence activities of trans-resveratrol and oxyresveratrol against uropathogenic Escherichia coli.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-10},
doi = {10.1080/08927014.2019.1657418},
pmid = {31505984},
issn = {1029-2454},
abstract = {Uropathogenic Escherichia coli (UPEC) is the primary causative agent of urinary tract infections, which are one of the most common infectious disease types in humans. UPEC infections involve bacterial cell adhesion to bladder epithelial cells, and UPEC can also form biofilms on indwelling catheters that are often tolerant to common antibiotics. In this study, the anti-biofilm activities of t-stilbene, stilbestrol, t-resveratrol, oxyresveratrol, ε-viniferin, suffruticosol A, and vitisin A were investigated against UPEC. t-Resveratrol, oxyresveratrol, and ε-viniferin, suffruticosol A, and vitisin A significantly inhibited UPEC biofilm formation at subinhibitory concentrations (10-50 μg ml-1). These findings were supported by observations that t-resveratrol and oxyresveratrol reduced fimbriae production and the swarming motility in UPEC. Furthermore, t-resveratrol and oxyresveratrol markedly diminished the hemagglutinating ability of UPEC, and enhanced UPEC killing by human whole blood. The findings show that t-resveratrol, oxyresveratrol, and resveratrol oligomers warrant further attention as antivirulence strategies against persistent UPEC infections.},
}
@article {pmid31505413,
year = {2019},
author = {Cao, J and Wang, Q and Ma, T and Bao, K and Yu, X and Duan, Z and Shen, X and Li, C},
title = {Effect of EGCG-gelatin biofilm on the quality and microbial composition of tilapia fillets during chilled storage.},
journal = {Food chemistry},
volume = {305},
number = {},
pages = {125454},
doi = {10.1016/j.foodchem.2019.125454},
pmid = {31505413},
issn = {1873-7072},
abstract = {The effects of the (-)-Epigallocatechin gallate (EGCG)-gelatin biofilm treatment (EGT) on microbial composition and quality of tilapia fillets stored at low temperatures were evaluated. The changes in mechanical properties, microbial reproduction, as well as lipid and protein oxidation during fillets storage were determined. The results showed that EGT reduced the microbial count and the relative abundance of the fillets. And EGT delayed the rate of lipid oxidation and protein denaturation in fillets. Compared with the control group, EGT samples had lower K values (74% on 18 d) and biogenic amines (39 mg/kg for putrescine and 50 mg/kg for cadaverine on 21 d). According to sensory evaluation, the shelf life of tilapia fillets was extended by 6 d in the EGT group. Therefore, EGT improved the quality of cryopreserved tilapia fillets and could be considered as a potential method for fish fillet preservation.},
}
@article {pmid31505403,
year = {2019},
author = {Ren, L and McCuskey, SR and Moreland, A and Bazan, GC and Nguyen, TQ},
title = {Tuning Geobacter sulfurreducens biofilm with conjugated polyelectrolyte for increased performance in bioelectrochemical system.},
journal = {Biosensors &amp; bioelectronics},
volume = {144},
number = {},
pages = {111630},
doi = {10.1016/j.bios.2019.111630},
pmid = {31505403},
issn = {1873-4235},
abstract = {Bioelectrochemical systems (BESs) are emerging as a platform technology with great application potentials such as wastewater remediation and power generation. Materials for electrode/microorganism modification are being examined in order to improve the current production in BESs. Herein, we report that the current production increased almost one fold in single-chamber BES reactors, by adding a conjugated polyelectrolyte (CPE-K) in the growth medium to co-form the anodic biofilm with Geobacter sulfurreducens cells. The CPE-K treated BESs had a maximum current density as high as 12.3 ± 0.5 A/m2, with that of the controls being 6.2 ± 0.7 A/m2. Improved current production was sustained even after CPE-K was no longer added to the medium. It was demonstrated that increased current resulted from improvement of certain biofilm properties. Analysis using electrochemical impedance spectroscopy (EIS) showed that CPE-K addition decreased the charge transfer resistance at the cell/electrode interface and the diffusion resistance through the biofilm. Protein quantification showed increased biomass growth on the electrode surface, and confocal scanning microscopy images revealed enhanced biofilm permeability. These results demonstrated for the first time that conjugated polyelectrolytes could be used for G. sulfurreducens biofilm augmentation to achieve high electricity production through tuning the anodic biofilm in BESs.},
}
@article {pmid31505308,
year = {2019},
author = {Cui, YX and Biswal, BK and van Loosdrecht, MCM and Chen, GH and Wu, D},
title = {Long term performance and dynamics of microbial biofilm communities performing sulfur-oxidizing autotrophic denitrification in a moving-bed biofilm reactor.},
journal = {Water research},
volume = {166},
number = {},
pages = {115038},
doi = {10.1016/j.watres.2019.115038},
pmid = {31505308},
issn = {1879-2448},
abstract = {Sulfide-oxidizing autotrophic denitrification (SOAD) implemented in a moving-bed biofilm reactor (MBBR) is a promising alternative to conventional heterotrophic denitrification in mainstream biological nitrogen removal. The sulfide-oxidation intermediate - elemental sulfur - is crucial for the kinetic and microbial properties of the sulfur-oxidizing bacterial communities, but its role is yet to be studied in depth. Hence, to investigate the performance and microbial communities of the aforementioned new biosystem, we operated for a long term a laboratory-scale (700 d) SOAD MBBR to treat synthetic saline domestic sewage, with an increase of the surface loading rate from 8 to 50 mg N/(m2·h) achieved by shortening the hydraulic retention time from 12 h to 2 h. The specific reaction rates of the reactor were eventually increased up to 0.37 kg N/(m3·d) and 0.73 kg S/(m3·d) for nitrate reduction and sulfide oxidation with no significant sulfur elemental accumulation. Two sulfur-oxidizing bacterial (SOB) clades, Sox-independent SOB (SOBI) and Sox-dependent SOB (SOBII), were responsible for indirect two-step sulfur oxidation (S2-→S0→SO42-) and direct one-step sulfur oxidation (S2-→SO42-), respectively. The SOBII biomass-specific electron transfer capacity could be around 2.5 times greater than that of SOBI (38 mmol e-/(gSOBII·d) versus 15 mmol e-/(gSOBI·d)), possibly resulting in the selection of SOBII over SOBI under stress conditions (such as a shorter HRT). Further studies on the methods and mechanism of selecting of SOBII over SOBI in biofilm reactors are recommended. Overall, the findings shed light on the design and operation of MBBR-based SOAD processes for mainstream biological denitrification.},
}
@article {pmid31504755,
year = {2019},
author = {Juin, C and Perrin, F and Puy, T and Bernard, C and Mollichella, ML and Girardot, M and Costa, D and Guillard, J and Imbert, C},
title = {Anti-biofilm activity of a semi-synthetic molecule obtained from resveratrol against Candida albicans biofilm.},
journal = {Medical mycology},
volume = {},
number = {},
pages = {},
doi = {10.1093/mmy/myz087},
pmid = {31504755},
issn = {1460-2709},
abstract = {Candida albicans can form biofilm on tissues and medical devices, becoming, in that case, less susceptible to antifungal agents. Treatment of candidiasis associated with the formation of C. albicans biofilms is restricted to echinocandins and lipid forms of amphotericin B. This study investigated the activity of micafungin and resveratrol modified molecule (EB487) against C. albicans biofilms. The anti-biofilm growth (Bgrowth) and anti-preformed biofilm (Bpreformed) activities of micafungin (0 to 3.94 μM) and EB487 (0 to 20.32 mM) were comparatively studied separately and combined, using XTT, flow cytometry and cell counts approaches. Concentrations causing 50% inhibition of the studied steps (IC50) were evaluated. When tested separately, IC50 Bgrowth was obtained for 4.8 mM and 0.13 μM of EB487 and micafungin respectively, and IC50 Bpreformed for 3.6 mM and 0.06 μM of EB487 and micafungin respectively. Micafungin used alone was not able to totally eradicate fungi. Micafungin combined with EB487 displayed synergistic activity (both anti-growth- and anti-preformed biofilm-activities). Optimal combination concentrations were EB487 (≤9.12 mM -strain ATCC 28367™ or ≤8.12 mM -strain CAI4-p), micafungin (≤0.05 μM for both) and caused a total eradication of fungi. Dose reduction indexes obtained using these concentrations were at least 9 (micafungin) and 3.2 (EB487) for both anti-biofilm growth- and anti-preformed biofilm-activities. Combinations indexes were consistently below one, demonstrating a synergistic relationship between micafungin and EB487 in these conditions. This study demonstrated the strong anti-biofilm activity of EB487 and highlighted its synergistic potential when combined with micafungin. EB487 is a promising semi-synthetic molecule with prophylactic and curative interests in fighting C. albicans biofilms.},
}
@article {pmid31503362,
year = {2019},
author = {Chan, WY and Hickey, EE and Page, SW and Trott, DJ and Hill, PB},
title = {Biofilm production by pathogens associated with canine otitis externa, and the antibiofilm activity of ionophores and antimicrobial adjuvants.},
journal = {Journal of veterinary pharmacology and therapeutics},
volume = {},
number = {},
pages = {},
doi = {10.1111/jvp.12811},
pmid = {31503362},
issn = {1365-2885},
support = {LP130100736//ARC Linkage Grant/ ; //Ministry of Higher Education/ ; //Universiti Putra Malaysia/ ; },
abstract = {Otitis externa (OE) is a frequently reported disorder in dogs associated with secondary infections by Staphylococcus, Pseudomonas and yeast pathogens. The presence of biofilms may play an important role in the resistance of otic pathogens to antimicrobial agents. Biofilm production of twenty Staphylococcus pseudintermedius and twenty Pseudomonas aeruginosa canine otic isolates was determined quantitatively using a microtiter plate assay, and each isolate was classified as a strong, moderate, weak or nonbiofilm producer. Minimum biofilm eradication concentration (MBEC) of two ionophores (narasin and monensin) and three adjuvants (N-acetylcysteine (NAC), Tris-EDTA and disodium EDTA) were investigated spectrophotometrically (OD570nm) and quantitatively (CFU/ml) against selected Staphylococcus and Pseudomonas biofilm cultures. Concurrently, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of planktonic cultures were assessed. 16/20 of the S. pseudintermedius clinical isolates were weak biofilm producers. 19/20 P. aeruginosa clinical isolates produced biofilms and were distributed almost equally as weak, moderate and strong biofilm producers. While significant antibiofilm activity was observed, no MBEC was achieved with narasin or monensin. The MBEC for NAC ranged from 5,000-10,000 µg/ml and from 20,000-80,000 µg/ml against S. pseudintermedius and P. aeruginosa, respectively. Tris-EDTA eradicated P. aeruginosa biofilms at concentrations ranging from 6,000/1,900 to 12,000/3,800 µg/ml. The MBEC was up to 16-fold and eightfold higher than the MIC/MBC of NAC and Tris-EDTA, respectively. Disodium EDTA reduced biofilm growth of both strains at concentrations of 470 µg/ml and higher. It can be concluded that biofilm production is common in pathogens associated with canine OE. NAC and Tris-EDTA are effective antibiofilm agents in vitro that could be considered for the treatment of biofilm-associated OE in dogs.},
}
@article {pmid31502909,
year = {2019},
author = {Silva, MD and Sillankorva, S},
title = {Otitis media pathogens - A life entrapped in biofilm communities.},
journal = {Critical reviews in microbiology},
volume = {},
number = {},
pages = {1-18},
doi = {10.1080/1040841X.2019.1660616},
pmid = {31502909},
issn = {1549-7828},
abstract = {Otitis media is a group of inflammatory diseases of the middle ear with great impact on children worldwide. The most common reported bacterial pathogens are Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. Over the last years, the role of biofilms formed by otopathogens that contribute to otitis media recurrence and chronicity has been established. An improved understanding of the properties of biofilms formed by these bacteria, which factors influence them, and how these affect the host inflammatory response is important for the development of novel strategies for the treatment of otitis media. This review focuses on the biofilm nature that the most prevalent otopathogens adopt in otitis media infections. In addition, new treatment approaches targeting biofilms are highlighted.},
}
@article {pmid31502331,
year = {2019},
author = {Ayyash, M and Shehabi, A and Mahmoud, NN and Al Bakri, AG},
title = {Anti-Biofilm Properties of Triclosan with EDTA or Cranberry as Foley Catheter Lock Solutions.},
journal = {Journal of applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jam.14439},
pmid = {31502331},
issn = {1365-2672},
abstract = {AIMS: To investigate the efficiency of triclosan, ethylenediaminetetraacetic acid (EDTA) and cranberry alone or in combinations against Escherichia coli (E. coli) strains as urinary catheter lock solutions to reduce catheter associated urinary tract infections.<br><br>METHODS AND RESULTS: Viable counting was used to assess anti-biofilm activities for triclosan, EDTA and cranberry alone or in combinations against E. coli strains embedded in biofilm onto all-silicon Foley catheter surface. The results revealed that combination of triclosan (10 mg/mL/ EDTA (30 mg/mL) when filling the catheter balloon was able to eradicate and prevent biofilm formation among all tested E.coli including the resistant strains, while triclosan (8.5 mg/mL)/ cranberry (103 mg/mL) combination was a successful catheter lock solution by preventing all tested strains from adhering onto catheter surface when filled via the eye hole.<br><br>CONCLUSIONS: The combinations of triclosan/EDTA and triclosan/cranberry were significantly effective in eradicating and preventing biofilm formation of the tested E. coli strains on Foley catheters.<br><br>Combinations of triclosan/EDTA and triclosan/cranberry have a promising application as non-antibiotic catheter lock solution.},
}
@article {pmid31501280,
year = {2019},
author = {Stewart, PS and White, B and Boegli, L and Hamerly, T and Williamson, KS and Franklin, MJ and Bothner, B and James, GA and Fisher, S and Vital-Lopez, FG and Wallqvist, A},
title = {Conceptual Model of Biofilm Antibiotic Tolerance that Integrates Phenomena of Diffusion, Metabolism, Gene Expression, and Physiology.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00307-19},
pmid = {31501280},
issn = {1098-5530},
abstract = {Transcriptomic, metabolomic, physiological, and computational modeling approaches were integrated to gain insight into the mechanisms of antibiotic tolerance in an in vitro biofilm system. Pseudomonas aeruginosa biofilms were grown in drip-flow reactors on a medium composed to mimic the exudate from a chronic wound. After four days, the biofilm was 114 μm thick with 9.45 log10 cfu cm-2 These biofilms exhibited tolerance, relative to exponential-phase planktonic cells, to subsequent treatment with ciprofloxacin. The biofilm specific growth rate was estimated via elemental balances to be approximately 0.37 h-1 and with a reaction-diffusion model to be 0.32 h-1 or one-third of the planktonic maximum specific growth rate. Global analysis of gene expression indicated decreased transcription of ribosomal genes and other anabolic functions in biofilms compared to exponential-phase planktonic cells and revealed the induction of multiple stress responses in biofilm cells including those associated with growth arrest, zinc limitation, hypoxia, and acyl-homoserine lactone quorum sensing. Metabolic pathways for phenazine biosynthesis and denitrification were transcriptionally activated in biofilms. A customized reaction-diffusion model predicted that steep oxygen concentration gradients form when these biofilms are thicker than about 40 μm. Mutant strains that were deficient in Psl polysaccharide synthesis, stringent response, stationary phase response, and membrane stress response exhibited increased ciprofloxacin susceptibility when cultured in biofilms. These results support a sequence of phenomena leading to biofilm antibiotic tolerance involving oxygen limitation, electron acceptor starvation and growth arrest, induction of associated stress responses, and differentiation into protected cell states.IMPORTANCE Bacteria in biofilms are protected from killing by antibiotics and this reduced susceptibility contributes to the persistence of infections such as those in the cystic fibrosis lung and chronic wounds. A generalized conceptual model of biofilm antimicrobial tolerance with these mechanistic steps is proposed: 1) establishment of concentration gradients in metabolic substrates and products; 2) active biological responses to these changes in the local chemical microenvironment; 3) entry of biofilm cells into a spectrum of states involving alternative metabolisms, stress responses, slow growth, cessation of growth, or dormancy (all prior to antibiotic treatment); 4) adaptive responses to antibiotic exposure; and 5) reduced susceptibility of microbial cells to antimicrobial challenges in some of the physiological states accessed through these changes.},
}
@article {pmid31501144,
year = {2019},
author = {Richards, JP and Cai, W and Zill, NA and Zhang, W and Ojha, AK},
title = {Adaptation of Mycobacterium tuberculosis to biofilm growth is genetically linked to drug tolerance.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.01213-19},
pmid = {31501144},
issn = {1098-6596},
abstract = {Mycobacterium tuberculosis (Mtb) spontaneously grows at the air-medium interface forming pellicle biofilms, which harbor more drug tolerant persisters than planktonic cultures. The underlying basis for increased persisters in Mtb biofilms is unknown. Using a Tn-seq approach, we show here that multiple genes that are necessary for fitness of Mtb cells within biofilms, but not in planktonic cultures, are also implicated in tolerance of bacilli to a diverse set of stressors and antibiotics. Thus, development of Mtb biofilms appears to be associated with an enrichment of population, in which challenging growth conditions within biofilm architecture select for cells that maintain intrinsic tolerance to exogenous stresses including antibiotic exposure. We further observed that the intrinsic drug tolerance of constituent cells of a biofilm determines the frequency of persisters. These findings together allow us to propose that the selection of elite cells during biofilm development promotes the frequency of persisters. Furthermore, probing the possibility that the population enrichment is an outcome of unique environment within biofilms, we demonstrate biofilm-specific induction in the synthesis of isonitrile lipopeptides (INLP). Mutation analysis indicates that INLP is necessary for the architecture development of Mtb biofilms. In summary, the study offers an insight into persistence of Mtb biofilms under antibiotic exposure, while identifying INLP as a potential biomarker for further investigation of this phenomenon.},
}
@article {pmid31500093,
year = {2019},
author = {Ratka, C and Weigl, P and Henrich, D and Koch, F and Schlee, M and Zipprich, H},
title = {The Effect of In Vitro Electrolytic Cleaning on Biofilm-Contaminated Implant Surfaces.},
journal = {Journal of clinical medicine},
volume = {8},
number = {9},
pages = {},
doi = {10.3390/jcm8091397},
pmid = {31500093},
issn = {2077-0383},
abstract = {PURPOSE: Bacterial biofilms are a major problem in the treatment of infected dental and orthopedic implants. The purpose of this study is to investigate the cleaning effect of an electrolytic approach (EC) compared to a powder-spray system (PSS) on titanium surfaces.<br><br>MATERIALS AND METHODS: The tested implants (different surfaces and alloys) were collated into six groups and treated ether with EC or PSS. After a mature biofilm was established, the implants were treated, immersed in a nutritional solution, and streaked on Columbia agar. Colony-forming units (CFUs) were counted after breeding and testing (EC), and control (PSS) groups were compared using a paired sample t-test.<br><br>RESULTS: No bacterial growth was observed in the EC groups. After thinning to 1:1,000,000, 258.1 ± 19.9 (group 2), 264.4 ± 36.5 (group 4), and 245.3 ± 40.7 (group 6) CFUs could be counted in the PSS groups. The difference between the electrolytic approach (test groups 1, 3, and 5) and PSS (control groups 2, 4, and 6) was statistically extremely significant (p-value < 2.2 × 10-16).<br><br>CONCLUSION: Only EC inactivated the bacterial biofilm, and PSS left reproducible bacteria behind. Within the limits of this in vitro test, clinical relevance could be demonstrated.},
}
@article {pmid31500048,
year = {2019},
author = {de Carvalho, FG and Magalhães, TC and Teixeira, NM and Gondim, BLC and Carlo, HL and Dos Santos, RL and de Oliveira, AR and Denadai, ÂML},
title = {Synthesis and characterization of TPP/chitosan nanoparticles: Colloidal mechanism of reaction and antifungal effect on C. albicans biofilm formation.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {104},
number = {},
pages = {109885},
doi = {10.1016/j.msec.2019.109885},
pmid = {31500048},
issn = {1873-0191},
abstract = {In the present study chitosan (Chit) nanoparticles were synthetized by the ionic gelation process, using tripolyphosphate (TPP) as crosslinking agent. The TPP/Chit nanoparticle formation was evaluated by titrations, measuring electrical conductivity (k), zeta potential (ZP), hydrodynamic diameter (Dh), viscosity (η) and heat by isothermal calorimetry (ITC). The antifungal effects were evaluated by C. albicans time-kill assays, inhibition of C. albicans initial adhesion and biofilm formation in comparison with nystatin and chitosan. Conductometric titration exhibited a typical precipitation profile, with an inflection at molar ratio of [TPP]/[Chitmon] ≈ 0.3, suggesting a 1:3.3 stoichiometry. The highest Dh, ZP and η values were shown at the beginning of titrations, due to the intramolecular repulsion between Chit-Chit. With addition of TPP, the values showed gradual reduction, with an intermediary transition at [TPP]/[Chitmon] ≈ 0.16, which was attributed to the partial breakdown of interchain crosslinking and formation of discrete charged aggregates. After this point, reaction should occur by neutralization of these assemblies, causing new reduction in values of Dh, ZP and η until [TPP]/[Chitmon] ≈ 0.3, when they reached their lowest values. ITC experiment also showed the occurrence of two bindings (K1 = 3.6 × 103 and K2 = 7.7 × 104), which were entropy driven. Biological results showed lower C. albicans viability for TPP/Chit over 24 h compared with chitosan and nystatin at MIC and 2 MIC. Moreover, TPP/Chit showed 25-50% inhibition of C. albicans adhesion and biofilm formation. The results showed that TPP/Chit nanoparticles reduced the initial adhesion and biofilm formation of C. albicans and demonstrated potential for use in a formulation for the treatment of oral candidiasis.},
}
@article {pmid31500022,
year = {2019},
author = {Jung, J and Li, L and Yeh, CK and Ren, X and Sun, Y},
title = {Amphiphilic quaternary ammonium chitosan/sodium alginate multilayer coatings kill fungal cells and inhibit fungal biofilm on dental biomaterials.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {104},
number = {},
pages = {109961},
doi = {10.1016/j.msec.2019.109961},
pmid = {31500022},
issn = {1873-0191},
abstract = {Formation of fungal biofilms on health care-related materials causes serious clinical consequences. This study reports a novel fungal repelling strategy to control fungal biofilm formation on denture biomaterials through layer-by-layer self-assembly (LBL). Amphiphilic quaternary ammonium chitosans (CS612) were synthesized and used as the antimicrobial positive layer, and sodium alginate (SA) was chosen as the negative layer to construct LBL multilayers on poly (methyl methacrylate) (PMMA)-based denture materials. The presence of LBL multilayers on denture disc was confirmed and characterized by surface zeta potential, water contact angle, AFM, and FT-IR analyses. The multilayer coatings, especially CS612 as the outmost layer, effectively prevented the fungal initial adhesion and biofilm formation. The Candida cells avoided the multilayer coatings and suspended in broth solution instead of forming biofilms, suggesting that the LBL multilayers had fungal repelling effects. The LBL multilayers were biocompatible toward mammalian cells. In stability tests, after immersion in PBS for 4 weeks under constant shaking and repeated brushing with a denture brush for up to 3000 times, the biofilm-controlling effects of the LBL multilayers were not affected, pointing to a novel long-term strategy in controlling fungal biofilms on denture and other related biomaterials.},
}
@article {pmid31499329,
year = {2019},
author = {Brück, HL and Delvigne, F and Dhulster, P and Jacques, P and Coutte, F},
title = {Molecular strategies for adapting Bacillus subtilis 168 biosurfactant production to biofilm cultivation mode.},
journal = {Bioresource technology},
volume = {293},
number = {},
pages = {122090},
doi = {10.1016/j.biortech.2019.122090},
pmid = {31499329},
issn = {1873-2976},
abstract = {Biofilm bioreactors have already been proven to be efficient systems for microbial lipopeptide production since they avoid foam formation. However, the cell adhesion capacities of the laboratory strain B.subtilis 168 to the biofilm bioreactor support are limited. In this work, we present a novel approach for increasing cell adhesion through the generation of filamentous and/or exopolysaccharide producing B.subtilis 168 mutants by genetic engineering. The single cell growth behavior was analyzed using time-lapse microscopy and the colonization capacities were investigated under continuous flow conditions in a drip-flow reactor. Cell adhesion could be increased three times through filamentous growth in lipopeptide producing B. subtilis 168 derivatives strains. Further restored exopolysaccharide production increased up to 50 times the cell adhesion capacities. Enhanced cell immobilization resulted in 10 times increased surfactin production. These findings will be of particular interest regarding the design of more efficient microbial cell factories for biofilm cultivation.},
}
@article {pmid31498302,
year = {2019},
author = {Depetris, A and Wiedmer, A and Wagner, M and Schäfer, S and Battin, TJ and Peter, H},
title = {Automated 3D Optical Coherence Tomography to Elucidate Biofilm Morphogenesis Over Large Spatial Scales.},
journal = {Journal of visualized experiments : JoVE},
volume = {},
number = {150},
pages = {},
doi = {10.3791/59356},
pmid = {31498302},
issn = {1940-087X},
abstract = {Biofilms are a most successful microbial lifestyle and prevail in a multitude of environmental and engineered settings. Understanding biofilm morphogenesis, that is the structural diversification of biofilms during community assembly, represents a remarkable challenge across spatial and temporal scales. Here, we present an automated biofilm imaging system based on optical coherence tomography (OCT). OCT is an emerging imaging technique in biofilm research. However, the amount of data that currently can be acquired and processed hampers the statistical inference of large scale patterns in biofilm morphology. The automated OCT imaging system allows covering large spatial and extended temporal scales of biofilm growth. It combines a commercially available OCT system with a robotic positioning platform and a suite of software solutions to control the positioning of the OCT scanning probe, as well as the acquisition and processing of 3D biofilm imaging datasets. This setup allows the in situ and non-invasive automated monitoring of biofilm development and may be further developed to couple OCT imaging with macrophotography and microsensor profiling.},
}
@article {pmid31497539,
year = {2019},
author = {Singh, VK and Mishra, A and Jha, B},
title = {Corrigendum: Anti-quorum Sensing and Anti-biofilm Activity of Delftia tsuruhatensis Extract by Attenuating the Quorum Sensing-Controlled Virulence Factor Production in Pseudomonas aeruginosa.},
journal = {Frontiers in cellular and infection microbiology},
volume = {9},
number = {},
pages = {308},
doi = {10.3389/fcimb.2019.00308},
pmid = {31497539},
issn = {2235-2988},
abstract = {[This corrects the article DOI: 10.3389/fcimb.2017.00337.].},
}
@article {pmid31493577,
year = {2019},
author = {Zhu, L and Chen, T and Xu, L and Zhou, Z and Feng, W and Liu, Y and Chen, H},
title = {Effect and mechanism of quorum sensing on horizontal transfer of multidrug plasmid RP4 in BAC biofilm.},
journal = {The Science of the total environment},
volume = {698},
number = {},
pages = {134236},
doi = {10.1016/j.scitotenv.2019.134236},
pmid = {31493577},
issn = {1879-1026},
abstract = {The widespread emergence of antibiotic resistance genes (ARGs) in drinking water systems endangers human health, and may be exacerbated by their horizontal gene transfer (HGT) among microbiota. In our previous study, Quorum sensing (QS) molecules produced by bacteria from biological activated carbon (BAC) biofilms were demonstrated to influence the transfer efficiency of a model conjugative plasmid, here RP4. In this study, we further explored the effect and mechanism of QS on conjugation transfer. The results revealed that Acyl-homoserine lactones producing (AHL-producing) bacteria isolated from BAC biofilm play a role in the propagation of ARGs. We selected several quorum sensing inhibitors (QSIs) to study their effects on AHL-producing bacteria, including the formation of biofilm and the regulating effect on conjugation transfer. In addition, the possible molecular mechanisms for AHLs that promote conjugative transfer were attributable to enhancing the mRNA expression, which involved altered expressions of conjugation-related genes. We also found that QSIs could inhibit conjugative transfer by downregulating the conjugation-relevant genes. We believe that this is the first insightful exploration of the mechanism by which AHLs will facilitate and QSIs will inhibit the conjugative transfer of ARGs. These results provide creative insight into ARG pollution control that involves blocking QS during BAC treatment in drinking water systems.},
}
@article {pmid31493571,
year = {2019},
author = {Ngan, WY and Habimana, O},
title = {From farm-scale to lab-scale: The characterization of engineered irrigation water distribution system biofilm models using an artificial freshwater source.},
journal = {The Science of the total environment},
volume = {698},
number = {},
pages = {134025},
doi = {10.1016/j.scitotenv.2019.134025},
pmid = {31493571},
issn = {1879-1026},
abstract = {Contaminants in freshwater environments, as well as the associated negative impacts on agricultural produce, have emerged as a critical theme of the water-energy-food nexus affecting food safety and irrigation management. Agricultural produce exposed to irrigation with questionable freshwater can internalize and concentrate pollutants. However, the potential risks posed by the ubiquitous presence of biofilms within irrigation water distribution systems (IWDS) remains overlooked, even though such biofilms may harbor and spread pathogenic, chemical, and other environmental pollutants. Our limited knowledge about the role and functional attributes of IWDS biofilms can be blamed mostly to experimental challenges encountered during attempted studies of these biofilms in their natural environments. Hence, a laboratory-based experimental system designed to simulate a freshwater environment was combined with a biofilm reactor capable of recreating the piping environments in water distribution systems. This experimental system was then tested to assess the robustness and repeatability of experimental early-stage biofilms with respect to physical structure and microbial community, using state-of-the-art confocal microscopy and next-generation sequencing, respectively. The results demonstrated the suitability of this laboratory-based experimental system for studying the impacts of selected pollutants on irrigation water distribution systems.},
}
@article {pmid31493408,
year = {2019},
author = {Milton, ME and Draughn, GL and Bobay, BG and Stowe, SD and Olson, AL and Feldmann, EA and Thompson, RJ and Myers, KH and Santoro, MT and Kearns, DB and Cavanagh, J},
title = {The Solution Structures and Interaction of SinR and SinI: Elucidating the Mechanism of Action of the Master Regulator Switch for Biofilm Formation in Bacillus subtilis.},
journal = {Journal of molecular biology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jmb.2019.08.019},
pmid = {31493408},
issn = {1089-8638},
abstract = {Bacteria have developed numerous protection strategies to ensure survival in harsh environments, with perhaps the most robust method being the formation of a protective biofilm. In biofilms, bacterial cells are embedded within a matrix that is composed of a complex mixture of polysaccharides, proteins and DNA. The Gram-positive bacterium Bacillus subtilis has become a model organism for studying regulatory networks directing biofilm formation. The phenotypic transition from a planktonic to biofilm state is regulated by the activity of the transcriptional repressor, SinR, and its inactivation by its primary antagonist, SinI. In this work, we present the first full-length structural model of tetrameric SinR using a hybrid approach combining high-resolution solution NMR, chemical crosslinking, mass spectrometry, and molecular docking. We also present the solution NMR structure of the antagonist SinI dimer, and probe the mechanism behind the SinR-SinI interaction using a combination of biochemical and biophysical techniques. As a result of these findings, we propose that SinI utilizes a residue replacement mechanism to block SinR multimerization, resulting in diminished DNA binding and concomitant decreased repressor activity. Finally, we provide an evidence-based mechanism that confirms how disruption of the SinR tetramer by SinI regulates gene expression.},
}
@article {pmid31493142,
year = {2019},
author = {Memariani, H and Memariani, M and Ghasemian, A},
title = {An overview on anti-biofilm properties of quercetin against bacterial pathogens.},
journal = {World journal of microbiology &amp; biotechnology},
volume = {35},
number = {9},
pages = {143},
doi = {10.1007/s11274-019-2719-5},
pmid = {31493142},
issn = {1573-0972},
abstract = {Bacterial biofilms are multicellular aggregates enclosed in a self-created biopolymer matrix. Biofilm-producing bacteria have become a great public health problem worldwide because biofilms enable these microorganisms to evade several clearance mechanisms produced by host and synthetic sources. Over the past years, different flavonoids including quercetin have engrossed considerable interest among researchers owing to their potential anti-biofilm properties. To our knowledge, there is no review regarding effects of quercetin towards bacterial biofilms, prompting us to summarize experimental evidence on its anti-biofilm properties. Quercetin inhibits biofilm development by a diverse array of bacterial pathogens such as Enterococcus faecalis, Staphylococcus aureus, Streptococcus mutans, Escherichia coli, and Pseudomonas aeruginosa. Prevention of bacterial adhesion, suppression of quorum-sensing pathways, disruption or alteration of plasma membrane, inhibition of efflux pumps, and blocking nucleic acid synthesis have been documented as major anti-biofilm mechanisms of quercetin. Overall, anti-biofilm activity of quercetin can open up new horizons in a wide range of biomedical areas, from food industry to medicine.},
}
@article {pmid31492289,
year = {2020},
author = {Harpale, K and Jagtap, K and Bankar, A and Dhole, S and More, M},
title = {Synthesis, Characterization and Anti-Biofilm Efficacy of Polypyrrole-Zinc Oxide Composites.},
journal = {Journal of nanoscience and nanotechnology},
volume = {20},
number = {4},
pages = {2639-2644},
doi = {10.1166/jnn.2020.17367},
pmid = {31492289},
issn = {1533-4899},
abstract = {A nanocomposite of Polypyrrole (PPy) and zinc oxide (ZnO), termed as PPy-ZnO, was synthesized by two step route. In the first step, synthesis of PPy was carried out by chemical oxidative route. In the second step, the PPy-ZnO nanocomposite was synthesized under hydrothermal conditions. The as-synthesized PPy-ZnO nanocomposites were characterized using X-ray Diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infra-red (FTIR) and Ultra violetvisible (UV-vis) spectroscopy to reveal the phase, morphology, chemical and optical properties. The physical and chemical characterizations confirmed presence of both PPy and ZnO phases in the nanocomposite. In the present work, antimicrobial activity of the PPy-ZnO nanocomposite against human pathogen Y. lipolytica has been investigated. Attempts have been made to reveal the influence of PPy percentage on the antimicrobial activity. Interestingly, all PPy-ZnO nanocomposites, irrespective of PPy percentage, showed 90 to 95% inhibited growth of Yarrowia lipolytica. The results obtained herein imply the potential of PPy-ZnO biofilm in inhibiting the growth of Y. lipolytica and thus preventing infections caused due to Y. lipolytica in humans.},
}
@article {pmid31491442,
year = {2019},
author = {Goeres, DM and Walker, DK and Buckingham-Meyer, K and Lorenz, L and Summers, J and Fritz, B and Goveia, D and Dickerman, G and Schultz, J and Parker, AE},
title = {Development, standardization, and validation of a biofilm efficacy test: The single tube method.},
journal = {Journal of microbiological methods},
volume = {},
number = {},
pages = {105694},
doi = {10.1016/j.mimet.2019.105694},
pmid = {31491442},
issn = {1872-8359},
abstract = {Methods validated by a standard setting organization enable public, industry and regulatory stakeholders to make decisions on the acceptability of products, devices and processes. This is because standard methods are demonstrably reproducible when performed in different laboratories by different researchers, responsive to different products, and rugged when small (usually inadvertent) variations from the standard procedure occur. The Single Tube Method (ASTM E2871) is a standard method that measures the efficacy of antimicrobials against biofilm bacteria that has been shown to be reproducible, responsive and rugged. In support of the reproducibility assessment, a six-laboratory study was performed using three antimicrobials: a sodium hypochlorite, a phenolic and a quaternary/alcohol blend, each tested at low and high efficacy levels. The mean log reduction in viable bacteria in this study ranged from 2.32 to 4.58 and the associated reproducibility standard deviations ranged from 0.89 to 1.67. Independent follow-up testing showed that the method was rugged with respect to deviations in sonication duration and sonication power but slightly sensitive to sonicator reservoir degassing and tube location within the sonicator bath. It was also demonstrated that when a coupon was dropped into a test tube, bacteria can splash out of reach of the applied antimicrobials, resulting in substantial bias when estimating log reductions for the products tested. Bias can also result when testing products that hinder the harvesting of microbes from test surfaces. The culmination of this work provided recommended changes to the early version of the standard method E2871-13 (ASTM, 2013b) including use of splashguards and microscopy checks. These changes have been incorporated into a revised ASTM method E2871-19 (ASTM 2019) that is the basis for the first regulatory method (ATMP-MB-20) to substantiate &quot;kills biofilm&quot; claims for antimicrobials registered and sold in the US.},
}
@article {pmid31490650,
year = {2019},
author = {Wang, JH and Zhao, Y and Chen, XY and Yang, Y and Wang, W and Wu, C and Yang, B and Zhang, Z and Zhang, LW and Liu, Y and Du, X and Li, W and Qiu, L and Jiang, P and Mou, XZ and Li, YQ},
title = {pH-Switchable Antimicrobial Nanofiber Networks of Hydrogel Eradicate Biofilm and Rescue Stalled Healing in Chronic Wound.},
journal = {ACS nano},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsnano.9b05608},
pmid = {31490650},
issn = {1936-086X},
abstract = {Biofilm infections can induce chronic inflammation and stall normal orchestrated course of wound healing cascades. Herein pH-switchable antimicrobial hydrogel with nanofiber networks for biofilm eradication and rescuing stalled healing in chronic wound is reported based on the self-assembly of a designed octapeptide (IKFQFHFD) at neutral pH. This hydrogel is biocompatible and exhibits acidic pH (pathological environment of infected chronic wounds)-switchable broad-spectrum antimicrobial effect via a mechanism involving cell wall and membrane disruption. The antimicrobial activity of hydrogel is derived from its acidic pH-dependent nanofiber networks destabilization and activated release of IKFQFHFD which is antimicrobial only at acidic pH due to the antimicrobial peptides-like molecular structure. In addition, supramolecular nanofiber networks loaded with drugs of cypate (photothermal agent) and proline (procollagen component) are further developed. In vitro experiments show that loaded drugs exhibit acidic pH (pH ~5.5)-responsive release profiles, and synergistic biofilm eradication and subsequent healing cascades activation of cells proliferation is achieved based on the supramolecular nanofiber networks. Remarkably, the nanofiber networks of hydrogel enables in vivo complete healing of MRSA biofilm-infected wound in diabetic mice within 20 days, showing great potential as promising chronic wound dressings. The proposed synergistic strategy for eradicating biofilm and activating subsequent healing cascades may offer a powerful modality for the management of clinical chronic wounds.},
}
@article {pmid31489410,
year = {2019},
author = {Wang, J and Zhao, S and Ran, SJ and Sun, Z and Liang, JP},
title = {[In vitro study of antimicrobial efficacy of different irrigations on Enterococcus faecalis biofilm formation in root canal].},
journal = {Shanghai kou qiang yi xue = Shanghai journal of stomatology},
volume = {28},
number = {3},
pages = {246-250},
pmid = {31489410},
issn = {1006-7248},
abstract = {PURPOSE: To compare the antimicrobial effect of different irrigations on Enterococcus faecalis biofilms in extracted teeth and evaluate the antimicrobial activity of irrigating solutions residual against E. faecalis biofilms formation, in order to provide a better strategy for clinician.<br><br>METHODS: Extracted human premolar teeth with single root canal were clearly autoclaved. These teeth were contaminated with E. faecalis（ATCC33186） and incubated for 60 days. The samples were randomly assigned to 4 experimental groups. During biomechanical instrumentation, the root canal was irrigated with different irrigating agents. The bacteria samples were collected with sterile paper points before and after instrumentation to F2. Then, samples that had been instrumented and autoclaved again were randomly divided into 2 groups treated with normal saline and 1%NaOCl for 30 min. E. faecalis was used to contaminate these root canals. The bacteria samples were collected with sterile paper points after 2, 6, 24, 48 h. SPSS19.0 software package was used for statistical analysis.<br><br>RESULTS: Group using 1% NaOCI with ultrasound devices was significantly more effective than NS alone groups. 1% NaOCI groups showed a better residual activity than NS group.<br><br>CONCLUSIONS: NaOCl is still the most important irrigating solutions, and it could be a better choice after biomechanical instrumentation, because of its long time substantivity achieves residual antimicrobial activity. Ultrasound devices is recommended to coordinate with irrigation.},
}
@article {pmid31489127,
year = {2019},
author = {Abdullah, N and Al-Marzooq, F and Mohamad, S and Abd Rahman, N and Chi Ngo, H and Perera Samaranayake, L},
title = {Intraoral appliances for in situ oral biofilm growth: a systematic review.},
journal = {Journal of oral microbiology},
volume = {11},
number = {1},
pages = {1647757},
doi = {10.1080/20002297.2019.1647757},
pmid = {31489127},
issn = {2000-2297},
abstract = {Background: Oral biofilms are the root cause of major oral diseases. As in vitro biofilms are not representative of the intraoral milieu, various devices have been manufactured over the years to develop Appliance Grown Oral Biofilm (AGOB). Objective: To review various intraoral appliances used to develop AGOB for microbiological analysis, and to judge the optimal means for such analyses. Design: Four databases (PubMed, Science Direct, Scopus and Medline) were searched by two independent reviewers, and articles featuring the key words 'device' OR 'splint' OR 'appliance'; 'Oral biofilm' OR 'dental plaque'; 'in vivo' OR 'in situ'; 'Microbiology' OR 'Bacteria' OR 'microbiome'; were included. The standard Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) were adopted for data gathering. Results: Of the 517 articles which met the initial inclusion criteria, 24 were deemed eligible for review. The age of the AGOB, sampled at various intervals, ranged from 30 min to 28 days. The most commonly used microbiome analytical methods were fluorescence microscopy, total cell count using conventional, and molecular tools including Next Generation Sequencing (NGS) platforms. Conclusions: No uniformly superior method for collecting AGOB could be discerned. NGS platforms are preferable for AGOB analyses.},
}
@article {pmid31487498,
year = {2019},
author = {Sheraton, MV and Melnikov, VR and Sloot, PMA},
title = {Prediction and Quantification of Bacterial Biofilm Detachment Using Glazier-Graner-Hogeweg Method Based Model Simulations.},
journal = {Journal of theoretical biology},
volume = {},
number = {},
pages = {109994},
doi = {10.1016/j.jtbi.2019.109994},
pmid = {31487498},
issn = {1095-8541},
abstract = {Morphological changes in bacterial biofilm structures arise from the fluid-structure interactions between the biofilm and the surrounding fluid. Depending on the magnitude of the force acting on the structure, the bacteria rearrange to attain an equilibrium shape or get washed away by the moving fluid. Understanding the dynamics behind the evolution of such equilibrium or failed states can aid in development of tools for biofilm removal or eradication. We develop a Glazier-Graner-Hogeweg method-based model to explore the collective evolution of biofilm morphology arising from cell-cell and cell-fluid interactions. We show that low adherence and high motility of the cells leads to sloughing of biofilms. Also, streamers are found to form under laminar flow conditions in tightly packed biofilms. In mixed species biofilms, we found that a species with less cell-cell binding affinity gets eroded faster than its counterpart. Therefore, we hypothesize that in nature these less-adherent species should be present encapsulated within the biofilm structure to maximize their chances of survival.},
}
@article {pmid31487117,
year = {2019},
author = {Malone, M and Schwarzer, S and Radzieta, M and Jeffries, T and Walsh, A and Dickson, HG and Micali, G and Jensen, SO},
title = {Effect on total microbial load and community composition with two vs six-week topical Cadexomer Iodine for treating chronic biofilm infections in diabetic foot ulcers.},
journal = {International wound journal},
volume = {},
number = {},
pages = {},
doi = {10.1111/iwj.13219},
pmid = {31487117},
issn = {1742-481X},
support = {//Smith and Nephew/ ; },
abstract = {This study compares two vs six weeks of topical antimicrobial therapy with Cadexomer Iodine in patients with diabetic foot ulcers (DFUs) complicated by chronic biofilm infections. Patients with non-healing DFUs with suspected chronic biofilm infections were eligible for enrolment. Patients were randomised to receive either two or six weeks of treatment with topical Cadexomer Iodine. Tissue biopsies from the ulcers were obtained pre-and-post treatment and underwent DNA sequencing and real-time quantitative polymerase chain reaction (PCR) to determine the total microbial load, community composition, and diversity of bacteria. Scanning electron microscopy confirmed biofilm in all 18 ulcers with suspected chronic biofilm infections. Cadexomer Iodine resulted in 14 of 18 (78%) samples achieving a mean 0.5 log10 reduction in microbial load. Regardless of treatment duration, there was no statistical difference in the reduction of total microbial loads. No difference in the rate of wound healing in the two groups was seen at 6 weeks. Cadexomer Iodine reduces the total microbial load in DFUs with chronic biofilm infections and affects microbial community composition and diversity. All ulcers in both groups showed an initial reduction in wound size with application of Cadexomer Iodine, which might reflect its effect on biofilms.},
}
@article {pmid31485973,
year = {2019},
author = {Vergis, J and Malik, SVS and Pathak, R and Kumar, M and Sunitha, R and Barbuddhe, SB and Rawool, DB},
title = {Efficacy of Indolicidin, Cecropin A (1-7)-Melittin (CAMA) and Their Combination Against Biofilm-Forming Multidrug-Resistant Enteroaggregative Escherichia coli.},
journal = {Probiotics and antimicrobial proteins},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12602-019-09589-8},
pmid = {31485973},
issn = {1867-1314},
support = {CAAST-ACLH (NAHEP/CAAST/2018-19)//NAHEP programme of ICAR/ ; },
abstract = {The present study examined the anti-biofilm efficacy of two short-chain antimicrobial peptides (AMPs), namely, indolicidin and cecropin A (1-7)-melittin (CAMA) against biofilm-forming multidrug-resistant enteroaggregative Escherichia coli (MDR-EAEC) isolates. The typical EAEC isolates re-validated by PCR and confirmed using HEp-2 cell adherence assay was subjected to antibiotic susceptibility testing to confirm its MDR status. The biofilm-forming ability of MDR-EAEC isolates was assessed by Congo red binding, microtitre plate assays and hydrophobicity index; broth microdilution technique was employed to determine minimum inhibitory concentrations (MICs) and minimum biofilm eradication concentrations (MBECs). The obtained MIC and MBEC values for both AMPs were evaluated alone and in combination against MDR-EAEC biofilms using crystal violet (CV) staining and confocal microscopy-based live/dead cell quantification methods. All the three MDR-EAEC strains revealed weak to strong biofilm-forming ability and were found to be electron-donating and weakly electron-accepting (hydrophobicity index). Also, highly significant (P < 0.001) time-dependent hydrodynamic growth of the three MDR-EAEC strains was observed at 48 h of incubation in Dulbecco's modified Eagle's medium (DMEM) containing 0.45% D-glucose. AMPs and their combination were able to inhibit the initial biofilm formation at 24 h and 48 h as evidenced by CV staining and confocal quantification. Further, the application of AMPs (individually and combination) against the preformed MDR-EAEC biofilms resulted in highly significant eradication (P < 0.001) at 24 h post treatment. However, significant differences were not observed between AMP treatments (individually or in combination). The AMPs seem to be an effective candidates for further investigations such as safety, stability and appropriate biofilm-forming MDR-EAEC animal models.},
}
@article {pmid31485710,
year = {2019},
author = {Raouia, H and Hamida, B and Khadidja, A and Ahmed, L and Abdelwaheb, C},
title = {Effect of static magnetic field (200 mT) on biofilm formation in Pseudomonas aeruginosa.},
journal = {Archives of microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00203-019-01719-8},
pmid = {31485710},
issn = {1432-072X},
abstract = {Several studies have investigated the effects of ionizing and non-ionizing radiations on microorganisms. However, the interaction between the magnetic field radiations and bacteria is less studied. The aim of our study was to study the effect of static magnetic field on the biofilm formation in Pseudomonas aeruginosa and its isogenic sod mutants. Our results revealed that the exposure to the static magnetic field (200 mT) increases significantly the swarming in the wild strain. The fliC gene expression did not show significant difference after 6 h exposure of the wild-type strain. The release of some compounds of the biofilm matrix such as rhamnolipids has been considerably enhanced after 6 h of exposure in the wild type. On the other hand, the pyocyanin and biofilm production was increased significantly in all strains compared to controls. Furthermore, our results revealed that the biofilm formation was confirmed by the pslA and ppyR gene expressions.},
}
@article {pmid31485510,
year = {2019},
author = {Hemdan, BA and El-Liethy, MA and ElMahdy, MEI and El-Taweel, GE},
title = {Metagenomics analysis of bacterial structure communities within natural biofilm.},
journal = {Heliyon},
volume = {5},
number = {8},
pages = {e02271},
doi = {10.1016/j.heliyon.2019.e02271},
pmid = {31485510},
issn = {2405-8440},
abstract = {The bacterial profiles of natural household biofilm have not been widely investigated. The majorities of these bacterial lineages are not cultivable. Thus, this study aims (i) to enumerate some potential bacterial lineages using culture based method within biofilm samples and confirmed using Biolog GEN III and polymerase chain reaction (PCR). (ii) To investigate the bacterial profiles of communities in two biofilm samples using next generation sequencing (NGS). Forty biofilm samples were cultured and colonies of each selected prevailing potential lineages (E. coli, Salmonella entrica, Pseudomonas aeruginosa, Staphylococcus aureus and Listeria monocytogenes) were selected for confirmation. From obtained results, the counts of the tested bacterial lineages in kitchen biofilm samples were greater than those in bathroom samples. Precision of PCR was higher than Biolog GEN III to confirm the bacterial isolates. Using NGS analysis, the results revealed that a total of 110,554 operational taxonomic units (OTUs) were obtained for two biofilm samples, representing kitchen and bathroom biofilm samples. The numbers of phyla in the kitchen biofilm sample (35 OTUs) was higher than that in bathroom sample (18 OTUs). A total of 435 genera were observed in the bathroom biofilm sample compared to only 256 in the kitchen sample. Evidences have shown that the empirical gadgets for biofilm investigation are becoming convenient and affordable. Many distinct bacterial lineages observed in biofilm are one of the most significant issues that threaten human health and lead to disease outbreaks.},
}
@article {pmid31485170,
year = {2019},
author = {Al-Shabib, NA and Husain, FM and Khan, RA and Khan, MS and Alam, MZ and Ansari, FA and Laeeq, S and Zubair, M and Shahzad, SA and Khan, JM and Alsalme, A and Ahmad, I},
title = {Interference of phosphane copper (I) complexes of β-carboline with quorum sensing regulated virulence functions and biofilm in foodborne pathogenic bacteria: A first report.},
journal = {Saudi journal of biological sciences},
volume = {26},
number = {2},
pages = {308-316},
doi = {10.1016/j.sjbs.2018.04.013},
pmid = {31485170},
issn = {1319-562X},
abstract = {Foodborne pathogens are one of the major cause of food-related diseases and food poisoning. Bacterial biofilms and quorum sensing (QS) mechanism of cell-cell communication have also been found to be associated with several outbreaks of foodborne diseases and are great threat to food safety. Therefore, In the present study, we investigated the activity of three tetrahedrally coordinated copper(I) complexes against quorum sensing and biofilms of foodborne bacteria. All the three complexes demonstrated similar antimicrobial properties against the selected pathogens. Concentration below the MIC i.e. at sub-MICs all the three complexes interfered significantly with the quorum sensing regulated functions in C. violaceum (violacein), P. aeruginosa (elastase, pyocyanin and alginate production) and S. marcescens (prodigiosin). The complexes demonstrated potent broad-spectrum biofilm inhibition in Pseudomonas aeruginosa, E. coli, Chromobacterium violaceum, Serratia marcescens, Klebsiella pneumoniae and Listeria monocytogenes. Biofilm inhibition was visualized using SEM and CLSM images. Action of the copper(I) complexes on two key QS regulated functions contributing to biofilm formation i.e. EPS production and swarming motility was also studied and statistically significant reduction was recorded. These results could form the basis for development of safe anti-QS and anti-biofilm agents that can be utilized in the food industry as well as healthcare sector to prevent food-associated diseases.},
}
@article {pmid31484626,
year = {2019},
author = {Cusumano, JA and Caffrey, AR and Daffinee, KE and Luther, MK and Lopes, V and LaPlante, KL},
title = {Weak biofilm formation among carbapenem-resistant Klebsiella pneumoniae.},
journal = {Diagnostic microbiology and infectious disease},
volume = {},
number = {},
pages = {114877},
doi = {10.1016/j.diagmicrobio.2019.114877},
pmid = {31484626},
issn = {1879-0070},
abstract = {Biofilm formation of multidrug and extensively drug resistant Klebsiella pneumoniae isolates is poorly understood. We investigated 139 diverse clinical K. pneumoniae isolates that possess various resistance patterns to evaluate the relationship between biofilm formation and resistance. Antimicrobial resistance was compared among a diverse collection of weak versus strong biofilm-forming K. pneumoniae, and predictors of strong biofilm formation were identified. Multi-drug resistant isolates were more common among weak (97.9%) versus strong biofilm formers (76%; P = 0.002). Carbapenem-resistant K. pneumoniae were 91% less likely to form strong biofilm (odds ratio 0.09; 95% confidence interval 0.02-0.33). The statistically significant inverse relationship between biofilm formation and antibiotic resistance suggests that virulence may be a trade-off for survival.},
}
@article {pmid31484288,
year = {2019},
author = {Nilsson, M and Givskov, M and Twetman, S and Tolker-Nielsen, T},
title = {Inactivation of the pgmA Gene in Streptococcus mutans Significantly Decreases Biofilm-Associated Antimicrobial Tolerance.},
journal = {Microorganisms},
volume = {7},
number = {9},
pages = {},
doi = {10.3390/microorganisms7090310},
pmid = {31484288},
issn = {2076-2607},
support = {DFF - 1323-00177//Natur og Univers, Det Frie Forskningsråd/ ; 11/1596//Tandlægefonden/ ; },
abstract = {Screening of a Streptococcus mutans mutant library indicated that pgmA mutants displayed a reduced biofilm-associated tolerance toward gentamicin. The biofilms formed by the S. mutanspgmA mutant also displayed decreased tolerance towards linezolid and vancomycin compared to wild-type biofilms. On the contrary, the resistance of planktonic S. mutanspgmA cells to gentamycin, linezolid, and vancomycin was more similar to wild-type levels. Investigations of biofilms grown in microtiter trays and on submerged glass slides showed that pgmA mutants formed roughly the same amount of biofilm as the wild type, indicating that the reduced antimicrobial tolerance of these mutants is not due to diminished biofilm formation. The pgmA gene product is known to be involved in the synthesis of precursors for cell wall components such as teichoic acids and membrane glycolipids. Accordingly, the S. mutanspgmA mutant showed increased sensitivity to Congo Red, indicating that it has impaired cell wall integrity. A changed cell wall composition of the S. mutanspgmA mutant may play a role in the increased sensitivity of S. mutanspgmA biofilms toward antibiotics.},
}
@article {pmid31484093,
year = {2019},
author = {Zhang, M and Yu, M and Wang, Y and He, C and Pang, J and Wu, J},
title = {Operational optimization of a three-stage nitrification moving bed biofilm reactor (NMBBR) by obtaining enriched nitrifying bacteria: Nitrifying performance, microbial community, and kinetic parameters.},
journal = {The Science of the total environment},
volume = {697},
number = {},
pages = {134101},
doi = {10.1016/j.scitotenv.2019.134101},
pmid = {31484093},
issn = {1879-1026},
abstract = {A two-sludge system consisting of A2/O (Anaerobic Anoxic Oxic) and NMBBR (Nitrification Moving Bed Biofilm Reactor) was developed. Stable and efficient denitrifying phosphorus removal can be realized by high-efficiency utilization of carbon sources in A2/O reactor with the electron acceptors of NOx--N in a three-stage NMBBR (consisting of N1, N2, N3). The three-stage NMBBR was successfully started within 18 days without additional inoculation sludge. Then a long-term operation (22-120 d) for the optimization of nitrifying performance, microbial community, and kinetic parameters was investigated. The biofilm characteristics (MLSS and biofilm thickness) and real-time control parameters (DO and pH) initially revealed the differences of three stages, while FISH results confirmed the optimizing nitrifying bacteria populations including AOB, Nitrobacteria and Nitrospira (N1: 5.94 ± 0.12%; N2: 8.26 ± 0.42%; N3: 10.06 ± 0.27% on day 50), basically consisting with the qPCR results (N1: 4.05%; N2: 8.04%; N3: 14.14%). The specific ammonium oxidation rate (SAOR: 3.24-10.02 mg/(gMLSS·h)) and temperature coefficient (θ: 1.008-1.011) based on temperature variation (15-35 °C) exhibited a strong resistant ability to low temperature operation. Moreover, half-saturation constants (KN,AOB, KN,NOB, KO,AOB and KO,NOB) fitted by Monod equation proved that DO diffusion played a significant role than substrate utilization (NH4+-N and NO2--N), but the diffusion resistance was negligible for flocs size smaller than 70 μm. Additionally, the dominant NOB (mainly Nitrospira) due to a higher KN,NOB and KO,NOB was more sensitive to mass transfer and diffusion resistance, which was helpful to understand the microbial competition for short-cut nitrification between AOB and NOB. Based on the above mechanism analysis, the MBBR optimization for the design and operation was put forward.},
}
@article {pmid31483869,
year = {2019},
author = {Wu, M and Xu, L and Cai, Z and Huang, S and Li, Y and Lei, L and Huang, X},
title = {Disinfection of Cariogenic Pathogens in Planktonic Lifestyle, Biofilm, and Carious Dentine with Antimicrobial Photodynamic Therapy.},
journal = {Photochemistry and photobiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/php.13161},
pmid = {31483869},
issn = {1751-1097},
abstract = {Antimicrobial photodynamic therapy (aPDT) has been recommended for clinical application. Its antibacterial effect on bacteria remained in dentinal tubule was seldom investigated. Here we evaluated the antibacterial effects of aPDT on Streptococcus mutans (S. mutans) and Lactobacillus acidophilus (L. acidophilus) in planktonic lifestyle, biofilm, and carious dentine. Mono-species biofilms or dentinal caries formed on human dentine slices or slabs. Bacterial suspension, biofilms, and dentine caries were treated with 0.1 mg/mL Toluidine Blue O followed by irradiation with a light emission diode (λ - 635±10 nm; 500 mW; 31.5 J/cm2 ; 60s) and 0.12% chlorhexidine (CHX), respectively. Residual bacteria were determined by microbial culture analysis and scanning electron microscopy. One-way analysis of variance (ANOVA) was performed to detect the significance of the variables. Both treatments significantly reduced the number of L. acidophilus in planktonic state, biofilm, and carious dentine (p < 0.05). For S. mutans, CHX was only bactericidal against suspension (p < 0.05) while aPDT was effective on both suspension and biofilm (p < 0.05) while not for dentin caries (p > 0.05). Under the experimental conditions assessed, aPDT could be an alternative disinfection method for superficial layer of caries cavity. Its disinfection on bacteria in dentinal tubule of deep layer was deficient. This article is protected by copyright. All rights reserved.},
}
@article {pmid31482327,
year = {2019},
author = {Bonsaglia, ECR and Latosinski, GS and Rossi, RS and Rossi, BF and Possebon, FS and Pantoja, JCF and Fernandes Júnior, A and Rall, VLM},
title = {Biofilm production under different atmospheres and growth media by Streptococcus agalactiae isolated from milk of cows with subclinical mastitis.},
journal = {Archives of microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00203-019-01727-8},
pmid = {31482327},
issn = {1432-072X},
abstract = {Different methods to analyze Streptococcus agalactiae biofilm formation have been investigated, but standardized protocols have not been developed. We compared S. agalactiae biofilm production among different atmospheres and growth media. Biofilm formation was studied in 32 isolates from bovine mastitis cases grown in Tryptone Soy Broth (TSB), Todd Hewitt Broth (THB), Luria Bertani Broth (LB) and Brain Heart Infusion (BHI), under two atmospheres, aerobic and 5% CO2. Regardless of the culture medium, growth under 5% CO2 resulted in a greater proportion of biofilm formation (65.63%), as compared with aerobic conditions (39.84%). Regardless of the atmosphere, the chances of biofilm formation were greater for isolates grown in TSB, as compared with THB [Odds ratio (OR) = 3.02], BHI (OR = 4.57), or LB (OR = 10.20). Thus, we suggest the use of 5% CO2 atmosphere and TSB in biofilm formation assays by Group-B streptococci (GBS) isolated from intramammary infections.},
}
@article {pmid31482119,
year = {2019},
author = {Wu, J and Li, F and Hu, X and Lu, J and Sun, X and Gao, J and Ling, D},
title = {Responsive Assembly of Silver Nanoclusters with a Biofilm Locally Amplified Bactericidal Effect to Enhance Treatments against Multi-Drug-Resistant Bacterial Infections.},
journal = {ACS central science},
volume = {5},
number = {8},
pages = {1366-1376},
doi = {10.1021/acscentsci.9b00359},
pmid = {31482119},
issn = {2374-7943},
abstract = {Bacterial biofilms pose a major threat to public health because they are resistant to most current therapeutics. Conventional antibiotics exhibit limited penetration and weakened activity in the acidic microenvironment of a biofilm. Here, the development of biofilm-responsive nanoantibiotics (rAgNAs) composed of self-assembled silver nanoclusters and pH-sensitive charge reversal ligands, whose bactericidal activity can be selectively boosted in the biofilm microenvironment, is reported. Under neutral physiological conditions, the bactericidal activity of rAgNAs is self-quenched because the toxic silver ions' release is largely inhibited; however, upon entry into the acidic biofilm microenvironment, the rAgNAs not only exhibit charge reversal to facilitate local accumulation and retention but also disassemble into small silver nanoclusters, thus enabling deep penetration and accelerated silver ions release for dramatically amplified bactericidal activity. The superior antibiofilm activity of rAgNAs is demonstrated both in vitro and in vivo, and the mortality rate of mice with multi-drug-resistant biofilm-induced severe pyomyositis can be significantly reduced by rAgNAs treatment, indicating the immense potential of rAgNAs as highly efficient nanoscale antibacterial agents to combat resistant bacterial biofilm-associated infections.},
}
@article {pmid31482007,
year = {2019},
author = {Keshvardoust, P and Huron, VAA and Clemson, M and Constancias, F and Barraud, N and Rice, SA},
title = {Biofilm formation inhibition and dispersal of multi-species communities containing ammonia-oxidising bacteria.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {22},
doi = {10.1038/s41522-019-0095-4},
pmid = {31482007},
issn = {2055-5008},
abstract = {Despite considerable research, the biofilm-forming capabilities of Nitrosomonas europaea are poorly understood for both mono and mixed-species communities. This study combined biofilm assays and molecular techniques to demonstrate that N. europaea makes very little biofilm on its own, and relies on the activity of associated heterotrophic bacteria to establish a biofilm. However, N. europaea has a vital role in the proliferation of mixed-species communities under carbon-limited conditions, such as in drinking water distribution systems, through the provision of organic carbon via ammonia oxidation. Results show that the addition of nitrification inhibitors to mixed-species nitrifying cultures under carbon-limited conditions disrupted biofilm formation and caused the dispersal of pre-formed biofilms. This dispersal effect was not observed when an organic carbon source, glucose, was included in the medium. Interestingly, inhibition of nitrification activity of these mixed-species biofilms in the presence of added glucose resulted in increased total biofilm formation compared to controls without the addition of nitrification inhibitors, or with only glucose added. This suggests that active AOB partially suppress or limit the overall growth of the heterotrophic bacteria. The experimental model developed here provides evidence that ammonia-oxidising bacteria (AOB) are involved in both the formation and maintenance of multi-species biofilm communities. The results demonstrate that the activity of the AOB not only support the growth and biofilm formation of heterotrophic bacteria by providing organic carbon, but also restrict and limit total biomass in mixed community systems.},
}
@article {pmid31481437,
year = {2019},
author = {Ribera, A and Benavent, E and El-Haj, C and Gomez-Junyent, J and Tubau, F and Rigo-Bonnin, R and Ariza, J and Murillo, O},
title = {Comparative anti-biofilm efficacy of meropenem alone and in combination with colistinin an in vitro pharmacodynamic model by extended-spectrum beta-lactamase-producing Klebsiella pneumoniae.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.01230-19},
pmid = {31481437},
issn = {1098-6596},
abstract = {We compared the efficacies of meropenem alone and in combination with colistin against two strains of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae, using an in vitro pharmacodynamic model that mimicked two different biofilm conditions. Meropenem in monotherapy achieved a remarkable efficacy (even a bactericidal effect) in all conditions, whereas colistin was almost inactive and resistance emerged. The addition of colistin to meropenem produced no relevant benefits in contrast with experiences with other microorganisms.},
}
@article {pmid31480443,
year = {2019},
author = {Gabe, V and Kacergius, T and Abu-Lafi, S and Zeidan, M and Abu-Farich, B and Austys, D and Masalha, M and Rayan, A},
title = {Suppressive Effects of Octyl Gallate on Streptococcus mutans Biofilm Formation, Acidogenicity, and Gene Expression.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {17},
pages = {},
doi = {10.3390/molecules24173170},
pmid = {31480443},
issn = {1420-3049},
abstract = {The accumulation of biofilm by Streptococcus mutans bacteria on hard tooth tissues leads to dental caries, which remains one of the most prevalent oral diseases. Hence, the development of new antibiofilm agents is of critical importance. The current study reports the results from testing the effectiveness of octyl gallate (C8-OG) against: (1) S. mutans biofilm formation on solid surfaces (polystyrene, glass), (2) acidogenicity, (3) and the expression of biofilm-related genes. The amount of biofilm formed by S. mutans bacteria was evaluated using the colorimetric method and optical profilometry. The pH of the biofilm growth medium was measured with microelectrode. A quantitative reverse transcription-polymerase chain reaction (RT-qPCR) was used to assess the expression of genes encoding glucan binding protein B (gbpB), glucosyltransferases B, -C, -D (gtfB, -C, -D), and the F-ATPase β subunit of the F1 protein (atpD). The results show that C8-OG significantly diminished biofilm formation by exposed S. mutans on solid surfaces and suppressed acidogenicity in a dose-dependent manner, compared to unexposed bacteria (p < 0.05). The C8-OG concentration of 100.24 µM inhibited S. mutans biofilm development on solid surfaces by 100% and prevented a decrease in pH levels by 99%. In addition, the RT-qPCR data demonstrate that the biofilm-producing bacteria treated with C8-OG underwent a significant reduction in gene expression in the case of the four genes under study (gbpB, gtfC, gtfD, and atpD), and there was a slight decrease in expression of the gtfB gene. However, C8-OG treatments did not produce significant expression change compared to the control for the planktonic cells, although there was a significant increase for the atpD gene. Therefore, C8-OG might be a potent antibiofilm and/or anticaries agent for oral formulations that aim to reduce the prevalence of dental caries.},
}
@article {pmid31479959,
year = {2019},
author = {Wu, Y and Cai, P and Jing, X and Niu, X and Ji, D and Ashry, NM and Gao, C and Huang, Q},
title = {Soil biofilm formation enhances microbial community diversity and metabolic activity.},
journal = {Environment international},
volume = {132},
number = {},
pages = {105116},
doi = {10.1016/j.envint.2019.105116},
pmid = {31479959},
issn = {1873-6750},
abstract = {Biofilms have been extensively studied in aquatic and clinical environments. However, the complexity of edaphic microenvironment hinders the advances toward understanding the environmental functionalities and ecological roles of soil biofilms. In this work, artificial soil was employed to investigate the soil biofilm formation and corresponding impacts on community structure and microbial activities. Our results showed that extracellular polymeric substances (EPS) production was significantly enhanced and micro-meter sized cell aggregates formed with high glucose amendment. Biofilm development exhibited significant effects on the soil microbial processes. 16S rRNA gene sequencing demonstrated the soils with biofilms and free-living cells shared similar microbial communities. But the Shannon diversity and evenness indices of communities with soil biofilms were significantly enhanced by 18.2% and 17.1%. The soil with biofilms also revealed a rapid response to nutrient provision and robust microbial activity, which consumed 65.4% more oxygen in the topsoil (0-1.5 mm). Kinetic respiration analysis showed that the enhanced metabolic activity was attributed to 23-times more active microbes in soil biofilms. In summary, this study revealed that soil biofilms can sustain a diverse and robust community to drive soil biogeochemical processes.},
}
@article {pmid31478651,
year = {2019},
author = {Dunsing, V and Irmscher, T and Barbirz, S and Chiantia, S},
title = {A purely polysaccharide-based biofilm matrix provides size-selective diffusion barriers for nanoparticles and bacteriophages.},
journal = {Biomacromolecules},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.biomac.9b00938},
pmid = {31478651},
issn = {1526-4602},
abstract = {Biofilms are complex mixtures of proteins, DNA and polysaccharides surrounding bacterial communities as protective barriers that can be biochemically modified during the bacterial life cycle. However, their compositional heterogeneity impedes a precise analysis of the contributions of individual matrix components to the biofilm structural organization. To investigate the structural properties of glycan-based biofilms, we analyzed the diffusion dynamics of nanometer-sized objects in matrices of the megadalton-sized anionic polysaccharide stewartan, the major biofilm component of the plant pathogen Pantoea stewartii. Fluorescence correlation spectroscopy and single particle tracking of nano-beads and bacteriophages indicated notable sub-diffusive dynamics dependent on probe size and stewartan concentration, in contrast to free diffusion of small molecules. Stewartan enzymatic depolymerization by bacteriophage tailspike proteins rapidly restored unhindered diffusion. We thus hypothesize that the glycan polymer stewartan determines major physico-chemical properties of the biofilm, which acts as a selective diffusion barrier for nanometer-sized objects and can be controlled by enzymes.},
}
@article {pmid31476321,
year = {2019},
author = {Tao, S and He, L and Xu, HHK and Weir, MD and Fan, M and Yu, Z and Zhang, M and Zhou, X and Liang, K and Li, J},
title = {Dentin remineralization via adhesive containing amorphous calcium phosphate nanoparticles in a biofilm-challenged environment.},
journal = {Journal of dentistry},
volume = {},
number = {},
pages = {103193},
doi = {10.1016/j.jdent.2019.103193},
pmid = {31476321},
issn = {1879-176X},
abstract = {OBJECTIVES: The remineralization of dentin at a bonded interface would help to strengthen the bonded interface and inhibit secondary caries, and would prolong the longevity of restoration. The aim of this study was to investigate the remineralization of demineralized human dentin in a dental biofilm environment via an adhesive containing nanoparticles of amorphous calcium phosphate (NACP).<br><br>METHODS: Dentin demineralization was promoted by subjecting samples to a Streptococcus mutans acidic biofilm for 24 h. Samples were divided into a control group, a commercial fluoride-releasing adhesive group, and an NACP adhesive group. All samples were subjected to a remineralization protocol consisting of 4-h exposure per 24-h period in brain heart infusion broth plus 1% sucrose (BHIS) followed by immersion in artificial saliva for the remaining period. The pH of BHIS after 4-h immersion was measured every other day. After 10 days, the biofilm was assessed for colony-forming unit (CFU) count, lactic acid production, live/dead staining, and calcium and phosphate content. The mineral changes in the demineralized dentin samples were analyzed by transverse microradiography, hardness measurement, X-ray diffraction characterization, and scanning electron microscopy.<br><br>RESULTS: The NACP adhesive achieved acid neutralization, decreased biofilm CFU count, decreased biofilm lactic acid production, and increased biofilm calcium and phosphate content (P < 0.05). The NACP adhesive group had higher remineralization value than the commercial fluoride-releasing adhesive group (P < 0.05).<br><br>CONCLUSIONS: The NACP adhesive was effective in remineralizing dentin lesions in a biofilm model. Its ability to protect bond interface, inhibit secondary caries, and prolong the longevity of restoration is promising.<br><br>CLINICAL SIGNIFICANCE: Using NACP-containing adhesives could be recommended because of the protective ability of its hybrid layer even under a biofilm-challenged environment.},
}
@article {pmid31475567,
year = {2019},
author = {Cheng, P and Osei-Wusu, D and Zhou, C and Wang, Y and Xu, Z and Chang, T and Huo, S},
title = {The effects of refractory pollutants in swine wastewater on the growth of Scenedesmus sp. with biofilm attached culture.},
journal = {International journal of phytoremediation},
volume = {},
number = {},
pages = {1-10},
doi = {10.1080/15226514.2019.1658706},
pmid = {31475567},
issn = {1549-7879},
abstract = {Microalgae have been widely used for treatment of swine wastewater. However, the research on combined treatment of refractory pollutants ammonia nitrogen, Cu (II) and antibiotics from swine wastewater was still scattered. This study, the growth and removal efficiency of NH4Cl, CuSO4, tetracycline, norfloxacin and sulfadimidine with selected Scenedsmus sp. was investigated by biofilm attached culture. The results showed that low concentration of ammonia nitrogen had little effect on algae growth. The highest biomass productivity was 6.2 g/(m2d) at the concentration of NH4Cl of 50.0 mg/L, which was similar to that of a standard growth medium BG 11. Cu (II) concentration of 1.0 mg/L could accelerate the growth of Scenedsmus sp., and the highest biomass was 57.2 g/m2 in 8 days. Moreover, the highest biomass mean values was 59.5 g/m2, 57.1 g/m2, and 58.1 g/m2, respectively, when tetracycline concentration was 20.0 mg/L, norfloxacin concentration was 100.0 mg/L and sulfadimidine concentration was 10.0 mg/L. The removal efficiency of ammonia nitrogen, copper, tetracycline, norfloxacin and sulfadimidine with Scenedsmus sp. at their optimal initial concentration by biofilm attached culture was 85.2%, 64.6%, 74.6%,71.2%, and 62.3%, respectively. This study provides a theoretical basis for the purification of refractory substances from swine wastewater.},
}
@article {pmid31474100,
year = {2019},
author = {Aracri, FM and Cavalcanti, RM and Guimarães, LHS},
title = {Extracellular Tannase from Aspergillus ochraceus: Influence of the Culture Conditions on Biofilm Formation, Enzyme Production, and Application.},
journal = {Journal of microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.4014/jmb.1903.03060},
pmid = {31474100},
issn = {1738-8872},
abstract = {Aspergillus ochraceus biofilm, developed on an inert support, can produce tannase in Khanna medium containing 1.5% (w/v) tannic acid as the carbon source, at an initial pH of 5.0, for 72 h at 28 °C. Addition of 0.1% yeast extract increased enzyme production. The enzyme in the crude filtrate exhibited the highest activity at 30 °C and pH 6.0. At 50 °C, the half-life (T50) was 60 min and 260 min at pH 6.0. In general, addition of detergents and surfactants did not affect tannase activity significantly. Tannase has potential applications in various biotechnological processes such as the production of propyl gallate and in the treatment of tannin-rich effluents. The content of tannins and total phenolic compounds in effluents from leather treatment was reduced by 56-83% and 47-64%, respectively, after 2 h of enzyme treatment. The content of tannins and total phenolic compounds in the sorghum flour treated for 120 h with tannase were reduced by 61% and 17%, respectively. Interestingly, the same A. ochraceus biofilm was able to produce tannase for three sequential fermentative process. In conclusion, fungal biofilm is an interesting alternative to produce high levels of tannase with biotechnological potential to be applied in different industrial sectors.},
}
@article {pmid31472077,
year = {2019},
author = {Patry, B and Lessard, P and Vanrolleghem, PA},
title = {Nitrification in a biofilm-enhanced highly loaded aerated lagoon.},
journal = {Water environment research : a research publication of the Water Environment Federation},
volume = {},
number = {},
pages = {},
doi = {10.1002/wer.1234},
pmid = {31472077},
issn = {1554-7531},
abstract = {A full-scale biofilm-enhanced aerated lagoon using fixed submerged media was monitored using automated water quality monitoring stations over the span of one year to quantify its nitrification performance. The system was operating at a high organic loading rate averaging 5.8 g total CBOD5 /m2 of media per day (23.9 g total CBOD5 /m3 of lagoon per day), a total ammonia nitrogen loading rate averaging 0.9 g NH4 -N/m2 ∙d (3.7 g NH4 -N/m3 ∙d) and temperatures ranging from 1.6°C to 20.8°C. The system showed an extended seasonal nitrification period compared to a simulated aerated lagoon system of the same dimensions. This extension of complete nitrification with approximately 1 month was observed in the fall despite the decrease of operating temperature down to 4°C. During this maximum nitrification period, substantial denitrification occurred, and the effluent un-ionized ammonia ratio was reduced. A temporary loss of nitrification was also experienced in relation to an episode of elevated suspended solids concentration. Measured biofilm characteristics, namely the detachment dynamics and the biofilm thickness, were used to explain this temporary nitrification loss. During wintertime, a low nitrate production was still observed, suggesting year-long retention of nitrifying bacteria in the biofilm.},
}
@article {pmid31470914,
year = {2019},
author = {Nascimento, MM},
title = {Approaches to Modulate Biofilm Ecology.},
journal = {Dental clinics of North America},
volume = {63},
number = {4},
pages = {581-594},
doi = {10.1016/j.cden.2019.07.002},
pmid = {31470914},
issn = {1558-0512},
abstract = {Dental caries is closely related to a dysbiosis of the microbial consortia of supragingival oral biofilms driven by a sugar-frequent and acidic-pH environment. The pH is a key factor affecting the homeostasis of supragingival biofilms seen in health. There is increasing interest on the ecological dynamics of the oral microbiome and how a dysbiotic microbiota can be successfully replaced by health-beneficial flora. The concept of preventing the microbial dysbiosis related to caries through modulation of sugar intake and pH has fully emerged.},
}
@article {pmid31470085,
year = {2019},
author = {Sahal, G and Woerdenbag, HJ and Hinrichs, WLJ and Visser, A and Tepper, PG and Quax, WJ and van der Mei, HC and Bilkay, IS},
title = {Antifungal and biofilm inhibitory effect of Cymbopogon citratus (lemongrass) essential oil on biofilm forming by Candida tropicalis isolates; an in vitro study.},
journal = {Journal of ethnopharmacology},
volume = {},
number = {},
pages = {112188},
doi = {10.1016/j.jep.2019.112188},
pmid = {31470085},
issn = {1872-7573},
abstract = {Cymbopogon citratus (lemongrass) essential oil has been widely used as a traditional medicine and is well known for antimicrobial properties. Therefore, it might be a potent anti-infective and biofilm inhibitive against Candida tropicalis infections. Until now, no ideal coating or cleaning method based on an essential oil has been described to prevent biofilm formation of Candida strains on silicone rubber maxillofacial prostheses, voice prostheses and medical devices susceptible to C. tropicalis infections.<br><br>AIM OF THE STUDY: To investigate the antifungal and biofilm inhibitory effects of Cymbopogon citratus oil. Clinical isolates of C. tropicalis biofilms on different biomaterials were used to study the inhibitory effect.<br><br>MATERIALS AND METHODS: The efficacy of Cymbopogon citratus, Cuminum cyminum, Citrus limon and Cinnamomum verum essential oils were compared on biofilm formation of three C. tropicalis isolates on 24 well polystyrene plates. C. citratus oil coated silicone rubber surfaces were prepared using hypromellose ointment as a vehicle. The antifungal tests to determine minimum inhibitory and minimum fungicidal concentrations were assessed by a microbroth dilution method and biofilm formation was determined by a crystal violet binding assay.<br><br>RESULTS: C. tropicalis strains formed more biofilm on hydrophobic materials than on hydrophilic glass. C. citratus oil showed a high antifungal effect against all C. tropicalis strains. For comparison, C. limon oil and C. cyminum oil showed minor to no killing effect against the C. tropicalis strains. C. citratus oil had the lowest minimal inhibitory concentration of all essential oils tested and inhibited biofilm formation of all C. tropicalis strains. C. citratus oil coating on silicone rubber resulted in a 45-76% reduction in biofilm formation of all C. tropicalis strains.<br><br>CONCLUSION: Cymbopogon citratus oil has good potential to be used as an antifungal and antibiofilm agent on silicone rubber prostheses and medical devices on which C. tropicalis biofilms form a serious risk for skin infections and may cause a shorter lifespan of the prosthesis.},
}
@article {pmid31469956,
year = {2019},
author = {Zhu, C and Zhang, M and Tang, Q and Yang, Q and Li, J and He, X and Ye, Y},
title = {Structure and Activity of the Camellia Oleifera Sapogenin Derivatives on Growth and Biofilm Inhibition of Staphylococcus aureus and Escherichia coli.},
journal = {Journal of agricultural and food chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.jafc.9b03577},
pmid = {31469956},
issn = {1520-5118},
abstract = {Sapogenin is the main block of Camellia oleifera saponin, which was purified and structurally modified by C28 acylation reaction to synthesize 19 new derivatives. The growth and biofilm inhibition of Staphylococcus aureus and Escherichia coli was measured to evaluate their antibacterial effects. Three-dimensional quantitative structure-activity relationship (3D-QSAR) assay indicated that the antibacterial activities were significantly enhanced after the sapogenin was modified with aromatic ring or heterocyclic ring and electron-withdrawing substituents at the meta or para position. Among them the derivative of sapogenin with 2-mercapto-4-methyl -5-thiazolyl acetyl group obviously destroyed bacterial biofilm and made bacteria lysis. 3D-QSAR provides practical information for structural design of sapogenin derivatives with strong antibacterial activity, and the Camellia oleifera sapogenin derivative 28-O-(2-mercapto-4-methyl-5-thiazolyl)- 3β,16α,21β,22α-O- tetrahydroxy- oleantel- 2-Ene- 23-aldehyde (S-16) is an effective candidate of antibacterial agent for prevention of bacterial resistance against antibiotics.},
}
@article {pmid31469892,
year = {2019},
author = {Perov, S and Lidor, O and Salinas, N and Golan, N and Tayeb-Fligelman, E and Deshmukh, M and Willbold, D and Landau, M},
title = {Structural Insights into Curli CsgA Cross-β Fibril Architecture Inspire Repurposing of Anti-amyloid Compounds as Anti-biofilm Agents.},
journal = {PLoS pathogens},
volume = {15},
number = {8},
pages = {e1007978},
doi = {10.1371/journal.ppat.1007978},
pmid = {31469892},
issn = {1553-7374},
abstract = {Curli amyloid fibrils secreted by Enterobacteriaceae mediate host cell adhesion and contribute to biofilm formation, thereby promoting bacterial resistance to environmental stressors. Here, we present crystal structures of amyloid-forming segments from the major curli subunit, CsgA, revealing steric zipper fibrils of tightly mated β-sheets, demonstrating a structural link between curli and human pathological amyloids. D-enantiomeric peptides, originally developed to interfere with Alzheimer's disease-associated amyloid-β, inhibited CsgA fibrillation and reduced biofilm formation in Salmonella typhimurium. Moreover, as previously shown, CsgA fibrils cross-seeded fibrillation of amyloid-β, providing support for the proposed structural resemblance and potential for cross-species amyloid interactions. The presented findings provide structural insights into amyloidogenic regions important for curli formation, suggest a novel strategy for disrupting amyloid-structured biofilms, and hypothesize on the formation of self-propagating prion-like species originating from a microbial source that could influence neurodegenerative diseases.},
}
@article {pmid31469013,
year = {2019},
author = {Sidrim, JJ and Amando, BR and Gomes, FI and do Amaral, MS and de Sousa, PC and Ocadaque, CJ and Brilhante, RS and A Cordeiro, R and Rocha, MF and Scm Castelo-Branco, D},
title = {Chlorpromazine-impregnated catheters as a potential strategy to control biofilm-associated urinary tract infections.},
journal = {Future microbiology},
volume = {14},
number = {},
pages = {1023-1034},
doi = {10.2217/fmb-2019-0092},
pmid = {31469013},
issn = {1746-0921},
abstract = {Aim: This study proposes the impregnation of Foley catheters with chlorpromazine (CPZ) to control biofilm formation by Escherichia coli, Proteus mirabilis and Klebsiella pneumoniae. Materials &amp; methods: The minimum inhibitory concentrations (MICs) for CPZ and the effect of CPZ on biofilm formation were assessed. Afterward, biofilm formation and the effect of ciprofloxacin and meropenem (at MIC) on mature biofilms grown on CPZ-impregnated catheters were evaluated. Results: CPZ MIC range was 39.06-625 mg/l. CPZ significantly reduced (p < 0.05) biofilm formation in vitro and on impregnated catheters. In addition, CPZ-impregnation potentiated the antibiofilm activity of ciprofloxacin and meropenem. Conclusion: These findings bring perspectives for the use of CPZ as an adjuvant for preventing and treating catheter-associated urinary tract infections.},
}
@article {pmid31468360,
year = {2019},
author = {Cacaci, M and Martini, C and Cinzia, G and Torelli, R and Bugli, F and Sanguinetti, M},
title = {Graphene Oxide Coatings as Tools to Prevent Microbial Biofilm Formation on Medical Device.},
journal = {Advances in experimental medicine and biology},
volume = {},
number = {},
pages = {},
doi = {10.1007/5584_2019_434},
pmid = {31468360},
issn = {0065-2598},
abstract = {The clinical challenge on surface engineering of medical devices to prevent microorganisms adhesion and biofilm formation, has become an essential aspect for medical implants. Antibacterial properties of Graphene Oxide (GO) have been demonstrated across a broad spectrum of bacteria, and the different mechanisms of action with which this nanomaterial interacts with the microbial surface have been elucidated in detail. Innovative protective coatings based on graphene film and hydrogel could represent an innovative solution for the prevention of nosocomial pathogens colonization on implantable device. This brief review mainly focuses on the applications of graphene in nanomedicine with a particular deepening on the antibacterial properties of GO and GO-based nanomaterials. In order to evaluate the possible future applications of GO as an anti-biofilm coating material for medical devices, studies on the ability of graphene coated surface to prevent microbial adhesion are also discussed. A concise review on in vitro toxicity and in vivo safety is also presented.},
}
@article {pmid31468316,
year = {2019},
author = {Vuotto, C and Donelli, G},
title = {Novel Treatment Strategies for Biofilm-Based Infections.},
journal = {Drugs},
volume = {},
number = {},
pages = {},
doi = {10.1007/s40265-019-01184-z},
pmid = {31468316},
issn = {1179-1950},
abstract = {Biofilm-growing cells show an enhanced antimicrobial tolerance with respect to the same cells growing in a free-floating way. This is due to physical or chemical diffusion barriers and increased transfer of resistance markers. Thus, tissue- and medical device-related biofilms can be considered among the leading sources of antibiotic treatment failure, causing many of the deadliest chronic infections afflicting humans nowadays. To find a satisfying way to counteract this major health threat, a great effort has been made in recent years to develop safe, effective and fast-acting anti-biofilm strategies. In this review, we summarise and evaluate the most promising tools and molecules that have demonstrated their ability to modulate steps involved in biofilm formation or to disperse pre-formed biofilms, without conferring evolutionary pressure to microorganisms.},
}
@article {pmid31467861,
year = {2019},
author = {Heuschkel, I and Hoschek, A and Schmid, A and Bühler, B and Karande, R and Bühler, K},
title = {Mixed-trophies biofilm cultivation in capillary reactors.},
journal = {MethodsX},
volume = {6},
number = {},
pages = {1822-1831},
doi = {10.1016/j.mex.2019.07.021},
pmid = {31467861},
issn = {2215-0161},
abstract = {The biocatalytic application of photoautotrophic organisms is a promising alternative for the production of biofuels and value-added compounds as they do not rely on carbohydrates as a source of carbon, electrons, and energy. Although the photoautotrophic organisms hold potential for the development of sustainable processes, suitable reactor concepts that allow high cell density (HCD) cultivation of photoautotrophic microorganisms are limited. Such reactors need a high surface to volume ratio to enhance light availability. Furthermore, the accumulation of high oxygen concentrations as a consequence of oxygenic photosynthesis, and its inhibitory effect on cell growth needs to be prevented. Here, we present a method for HCD cultivation of oxygenic phototrophs based on the co-cultivation of different trophies in a biofilm format to avoid high oxygen partial-pressure and attain HCDs of up to 51.8 gBDW L-1 on a lab scale. In this article, we show: •A robust method for mixed trophies biofilm cultivation in capillary reactors•Set-up and operation of a biofilm capillary reactor•A method to quantify oxygen in the continuous biofilm capillary reactor.},
}
@article {pmid31467830,
year = {2019},
author = {Gozoua, E and Koffi-Nevry, R and Blache, Y},
title = {Biofilm formation in marine bacteria and biocidal sensitivity: interplay between a potent antibiofilm compound (AS162) and quorum-sensing autoinducers.},
journal = {3 Biotech},
volume = {9},
number = {9},
pages = {338},
doi = {10.1007/s13205-019-1866-6},
pmid = {31467830},
issn = {2190-572X},
abstract = {The capacity of two homoserine lactones to stimulate the marine bacteria Pseudoalteromonas ulvae (TC14 strain) for its capacity to form a biofilm when exposed to a potent antibiofilm compound AS162 is reported. Effective concentrations (EC50) of AS162 at 24 h, 48 h, and 72 h were, respectively, of 4.3, 4.4, and 6.0 µM. When tested in combination with HSLs, results showed that quorum-sensing signal molecules 3-oxo-C6 and 3-oxo-C8 homoserine lactones do not act directly on the biofilm formation, but are able to interfere positively with AS162 to promote biofilm growth with EC50 ranging from 30 to 50 µM. The same results were obtained with two other marine bacterial strains: Pseudoalteromonas lipolytica TC8 and Paracoccus sp. 4M6. These findings suggest that HSLs can significantly affect the biocidal sensitivity of marine bacteria to antifouling agents.},
}
@article {pmid31466323,
year = {2019},
author = {Senpuku, H and Nakamura, T and Iwabuchi, Y and Hirayama, S and Nakao, R and Ohnishi, M},
title = {Effects of Complex DNA and MVs with GTF Extracted from Streptococcus mutans on the Oral Biofilm.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {17},
pages = {},
doi = {10.3390/molecules24173131},
pmid = {31466323},
issn = {1420-3049},
support = {21390506, 24659821, 16K11537//Japan Society for the Promotion of Science/ ; 40105502//Japan Agency for Medical Research and Development/ ; },
abstract = {Streptococcus mutans is one of the principal pathogens for the development of dental caries. Oral biofilms formed by S. mutans are constructed of insoluble glucan formation induced by the principal enzymes, GTF-I and GTF-SI, in sucrose-containing conditions. However, as another means of biofilm formation, extracellular DNA (eDNA) and membrane vesicles (MVs) are also contributors. To explore the roles of eDNA and MVs for biofilm formation, short and whole size pure DNAs, two types of sub-purified DNAs and MVs were extracted from S. mutans by beads destruction, treatment of proteinase K, and ultracentrifugation of culture supernatant, and applied into the biofilm formation assay using the S. mutans UA159 gtfBC mutant, which lost GTF-I and GTF-SI, on a human saliva-coated 96 well microtiter plate in sucrose-containing conditions. Sub-purified DNAs after cell lysis by beads destruction for total 90 and 180 s showed a complex form of short-size DNA with various proteins and MVs associated with GTF-I and GTF-SI, and induced significantly higher biofilm formation of the S. mutans UA159.gtfBC mutant than no sample (p < 0.05). Short-size pure DNA without proteins induced biofilm formation but whole-size pure DNA did not. Moreover, the complex form of MV associated with GTFs and short-size DNA showed significantly higher biofilm formation of initial colonizers on the human tooth surface such as Streptococcus mitis than no sample (p < 0.05). The short-size DNAs associated with MVs and GTFs are important contributors to the biofilm formation and may be one of additional targets for the prevention of oral biofilm-associated diseases.},
}
@article {pmid31466002,
year = {2019},
author = {Herath, BS and Sathasivan, A},
title = {The chloramine stress induces the production of chloramine decaying proteins by microbes in biomass (biofilm).},
journal = {Chemosphere},
volume = {238},
number = {},
pages = {124526},
doi = {10.1016/j.chemosphere.2019.124526},
pmid = {31466002},
issn = {1879-1298},
abstract = {In this paper, for the first time, we show in chloraminated systems, the chloramine decaying proteins (CDP) play an important role in bulk water and biomass (biofilm) in resisting disinfectant. Extracellular polymeric substances in biofilm/biomass are known to protect microbes from disinfectants and toxic materials, but the exact mechanism(s) is/are not known. Starting with the seed from a nitrifying chloraminated reactor, two 5 L reactors were fed intermittently with either chloramine or ammonia containing nutrient solution. The degree of nitrification increased with time in both reactors despite an increase in soluble CDP in the chloraminated reactor, while soluble CDP decreased in the ammoniated one. The suspended biomass collected after eight months of operation from chloraminated reactor contained CDP and responded to short-term chloramine stress (1.5 h with initial 1.5 mg-Cl2·L-1) by the additional production of soluble CDP. The suspended biomass from ammoniated reactor neither contained CDP nor produced soluble CDP as a stress response. The production, release and accumulation of CDP in biomass (biofilm) could be one of several mechanisms microbes use to defend against disinfectants (stress). The new understanding will pave the way for better disinfection management and better design of experiments.},
}
@article {pmid31465921,
year = {2019},
author = {Fan, X and Peng, P and Huang, H and Peng, C and Gao, Y and Ren, H},
title = {Undesirable effects of exogenous N-acyl homoserine lactones on moving bed biofilm reactor treating medium-strength synthetic wastewater.},
journal = {The Science of the total environment},
volume = {696},
number = {},
pages = {134061},
doi = {10.1016/j.scitotenv.2019.134061},
pmid = {31465921},
issn = {1879-1026},
abstract = {Exogenous AHLs are gradually reported to facilitate biofilm growth, however, whether they play a universal role in promoting biofilm formation and pollutants removal remains to be investigated. The pollutant removal, biofilm properties, microbial community and the distribution of AHLs were investigated in three lab-scale MBBRs by continuous dosing 100 nM N-Hexanoyl-L-homoserine lactone (C6-HSL) and N-Octanoyl-L-homoserine lactone (C8-HSL) in synthetic wastewater under normal nutrition (40 mg/L NH4+-N with C/N = 20). Results showed that adding AHLs didn't affect organics removal and exogenous C6-HSL even significantly suppressed NH4+-N removal by 0.44-20.29% after 16 days (p < 0.05). The introduction of AHLs both facilitated biofilm growth and extracellular polymeric substances secretion while suppressed ATP production especially during the stable operation period, with 48.96% by C6-HSL (p < 0.05) and 27.25% by C8-HSL, respectively. Exogenous AHLs inhibited the proliferation of Chryseobacterium, resulting in improvement in biofilm growth and it probably mediated ATP synthesis through regulating the release of 3OHC12-HSL in aqueous phase. Organics removal and biofilm growth were mainly attributed to the combined actions of multitudinous AHLs in biofilm phase rather than that in aqueous phase. The counterintuitive conclusions obtained in this study highlighted the importance of legitimately applying exogenous AHLs to accelerate biofilm formation and the start-up of MBBR in wastewater treatment.},
}
@article {pmid31464096,
year = {2019},
author = {Hong, L and Liu, X and Tan, L and Cui, Z and Yang, X and Liang, Y and Li, Z and Zhu, S and Zheng, Y and Yeung, KWK and Jing, D and Zheng, D and Wang, X and Wu, S},
title = {Rapid Biofilm Elimination on Bone Implants Using Near-Infrared-Activated Inorganic Semiconductor Heterostructures.},
journal = {Advanced healthcare materials},
volume = {},
number = {},
pages = {e1900835},
doi = {10.1002/adhm.201900835},
pmid = {31464096},
issn = {2192-2659},
support = {51671081//NSFC/ ; 51871162//NSFC/ ; 51801056//NSFC/ ; 2016YFC1100600//National Key Research and Development Program of China/ ; 2016YFC1100604//National Key Research and Development Program of China/ ; 2018CFA064)//Natural Science Fund of Hubei Province/ ; },
abstract = {Bacterial infections often cause orthopedic surgery failures. It is hard for the immune system and antibiotics to clear bacteria adhered to implants after they form a mature biofilm, and a secondary surgery is required to remove the infected implants. To avoid this, a hybrid coating of Bi2 S3 @Ag3 PO4 /Ti is prepared to eliminate biofilm using near-infrared (NIR) light. Bi2 S3 nanorod (NR) arrays are prepared on titanium (Ti) implants through hydrothermal methods, and Ag3 PO4 nanoparticles (NPs) are loaded on Bi2 S3 NR arrays using a stepwise electrostatic adsorption strategy. The introduction of Ag3 PO4 NPs enhances the photocatalysis performances of Bi2 S3 , and the hybrid coating also exhibits good photothermal effects. After 808 nm light irradiation for 15 min, it shows superior bactericidal efficiency of 99.45% against Staphylococcus aureus, 99.74% against Escherichia coli in vitro, and 94.54% against S. aureus biofilm in vivo. Bi2 S3 @Ag3 PO4 /Ti also shows good cell viability compared to pure Ti. This NIR-activated-inorganic hybrid semiconductor heterojunction coating is biocompatible and could be employed to eliminate biofilm effectively, which makes it a very promising strategy for the surface modification of bone implant materials.},
}
@article {pmid31463386,
year = {2019},
author = {Gebreyohannes, G and Nyerere, A and Bii, C and Sbhatu, DB},
title = {Challenges of intervention, treatment, and antibiotic resistance of biofilm-forming microorganisms.},
journal = {Heliyon},
volume = {5},
number = {8},
pages = {e02192},
doi = {10.1016/j.heliyon.2019.e02192},
pmid = {31463386},
issn = {2405-8440},
abstract = {Background: Biofilms are multicellular communities of microorganisms held together by a self-produced extracellular matrix. The ability of microbes to form biofilm is a universal, ubiquitous, and dynamic process. This dynamic process of biofilms establishes an important strategy to withstand and survive harsh environmental conditions and antimicrobial agents.<br><br>Objective: This review paper aims to give an overview of antibiotic resistance, intervention, and treatment of infections caused by biofilm-forming organisms. Moreover, it can also help to motivate scholars to search for new anti-biofilm strategies and most appropriate methods to tackle the effect of biofilm infections on healthcare services.<br><br>Methods: This paper was written by reviewing recent research and review articles which are reporting about the antibiotic resistance, prevention, and treatment of biofilm-producing organisms.<br><br>Conclusion: Bioprospecting for quorum quenching compounds can be an appropriate solution for controlling biofilm infections.},
}
@article {pmid31461929,
year = {2019},
author = {Zhang, B and Zhuang, X and Guo, L and McLean, RJC and Chu, W},
title = {Recombinant N-acyl homoserine lactone-Lactonase AiiAQSI-1 Attenuates Aeromonas hydrophila Virulence Factors, Biofilm Formation and Reduces Mortality in Crucian Carp.},
journal = {Marine drugs},
volume = {17},
number = {9},
pages = {},
doi = {10.3390/md17090499},
pmid = {31461929},
issn = {1660-3397},
support = {31672676//National Natural Science Foundation of China/ ; PAPD//Priority Academic Program Development of Jiangsu Higher Education Institutions/ ; },
abstract = {Quorum quenching (QQ) is a promising alternative infection-control strategy to antibiotics that controls quorum-regulated virulence without killing the pathogens. Aeromonas hydrophila is an opportunistic gram-negative pathogen living in freshwater and marine environments. A. hydrophila possesses an N-acyl homoserine lactone (AHL)-based quorum-sensing (QS) system that regulates virulence, so quorum signal-inactivation (i.e., QQ) may represent a new way to combat A. hydrophila infection. In this study, an AHL lactonase gene, aiiA was cloned from Bacillus sp. strain QSI-1 and expressed in Escherichia coli strain BL21(DE3). The A. hydrophila hexanoyl homoserine lactone (C6-HSL) QS signal molecule was degraded by AiiAQSI-1, which resulted in a decrease of bacterial swimming motility, reduction of extracellular protease and hemolysin virulence factors, and inhibited the biofilm formation of A. hydrophila YJ-1 in a microtiter assay. In cell culture studies, AiiAQSI-1 decreased the ability of A. hydrophila adherence to and internalization by Epithelioma papulosum cyprini (EPC) cells. During in vivo studies, oral administration of AiiAQSI-1 via feed supplementation attenuated A. hydrophila infection in Crucian Carp. Results from this work indicate that feed supplementation with AiiAQSI-1 protein has potential to control A. hydrophila aquaculture disease via QQ.},
}
@article {pmid31459295,
year = {2018},
author = {Gupta, P and Gupta, S and Sharma, M and Kumar, N and Pruthi, V and Poluri, KM},
title = {Effectiveness of Phytoactive Molecules on Transcriptional Expression, Biofilm Matrix, and Cell Wall Components of Candida glabrata and Its Clinical Isolates.},
journal = {ACS omega},
volume = {3},
number = {9},
pages = {12201-12214},
doi = {10.1021/acsomega.8b01856},
pmid = {31459295},
issn = {2470-1343},
abstract = {Toxicity challenges by antifungal arsenals and emergence of multidrug resistance scenario has posed a serious threat to global community. To cope up with this alarming situation, phytoactive molecules are richest, safest, and most effective source of broad spectrum antimicrobial compounds. In the present investigation, six phytoactive molecules [cinnamaldehyde (CIN), epigallocatechin, vanillin, eugenol (EUG), furanone, and epigallocatechin gallate] were studied against Candida glabrata and its clinical isolates. Among these, CIN and EUG which are active components of cinnamon and clove essential oils, respectively, exhibited maximum inhibition against planktonic growth of C. glabrata at a concentration of 64 and 128 μg mL-1, respectively. These two molecules effectively inhibited and eradicated approximately 80% biofilm of C. glabrata and its clinical isolates from biomaterials. CIN and EUG increased reactive oxygen species generation, cell lysis, and ergosterol content in plasma membrane and reduced virulence attributes (phospholipase and proteinase) as well as catalase activity of C. glabrata cells. Reduction of mitochondrial membrane potential with increased release of cytochrome c from mitochondria to cytosol indicated initiation of early apoptosis in CIN- and EUG-treated C. glabrata cells. Transcriptional analysis showed that multidrug transporter (CDR1) and ergosterol biosynthesis genes were downregulated in the presence of CIN, while getting upregulated in EUG-treated cells. Interestingly, genes such as 1,3-β-glucan synthase (FKS1), GPI-anchored protein (KRE1), and sterol importer (AUS1) were downregulated upon treatment of CIN/EUG. These results provided molecular-level insights about the antifungal mechanism of CIN and EUG against C. glabrata including its resistant clinical isolate. The current data established that CIN and EUG can be potentially formulated in new antifungal strategies.},
}
@article {pmid31456753,
year = {2019},
author = {Zago, PMW and Dos Santos Castelo Branco, SJ and de Albuquerque Bogéa Fecury, L and Carvalho, LT and Rocha, CQ and Madeira, PLB and de Sousa, EM and de Siqueira, FSF and Paschoal, MAB and Diniz, RS and Gonçalves, LM},
title = {Anti-biofilm Action of Chenopodium ambrosioides Extract, Cytotoxic Potential and Effects on Acrylic Denture Surface.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1724},
doi = {10.3389/fmicb.2019.01724},
pmid = {31456753},
issn = {1664-302X},
abstract = {Considering the challenge to control Candida-associated denture stomatitis, the search for antifungal substances derived from natural sources has become a trend in the literature. In this study the following effects of Chenopodium ambrosioides extract (CAE) were investigated: action against biofilms of Candida albicans, its cytotoxic potential, and changes caused in acrylic resin. The CAE was characterized by High Performance Liquid Chromatography (HPLC). The susceptibility of C. albicans to CAE was investigated by Minimum Inhibitory Concentration and Minimum Fungicidal Concentration (MIC and MFC) tests. Acrylic resin disks were fabricated, and C. albicans biofilms were developed on these for 48 h. Afterward the disks were immersed for 10 min in: PBS (Negative Control); 1% Sodium Hypochlorite (1% SH, Positive Control) or CAE at MIC or 5xMIC. The biofilms were investigated relative to counts and metabolic activity. The cytotoxic potential in keratinocytes and fibroblasts was verified by MTT test. Change in color and roughness of the acrylic resin was analyzed after 28 days of immersion in CAE. The data were analyzed by the ANOVA considering a 5% level of significance. The main compounds detected by HPLC were kaempferol and quercetin. Both MIC and MFC obtained the value of 0.25 mg/mL. The MIC was sufficient to significantly reduce the counts and activity of the biofilm cells (p < 0.0001), while 5xMIC resulted in almost complete eradication, similar to 1% SH. Keratinocytes and fibroblasts exposed to the MIC and 5xMIC presented cell viability similar to that of the Control Group (p > 0.05). No important changes in acrylic resin color and roughness were detected, even after 28 days. It could be concluded that the immersion of acrylic resin in C. ambrosioides extract in its minimum inhibitory concentration was effective for the reduction of C. albicans biofilms without any evidence of cytotoxic effects or changes in roughness and color of this substrate.},
}
@article {pmid31456169,
year = {2019},
author = {Andre, C and de Jesus Pimentel-Filho, N and de Almeida Costa, PM and Vanetti, MCD},
title = {Changes in the composition and architecture of staphylococcal biofilm by nisin.},
journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]},
volume = {},
number = {},
pages = {},
doi = {10.1007/s42770-019-00135-w},
pmid = {31456169},
issn = {1678-4405},
support = {APQ 02600-14-1//FAPEMIG/ ; },
abstract = {Bacterial biofilms are involved in various medical infections and food contamination episodes and, for this reason, it is of great importance to developing new strategies of its prevention and control. The subinhibitory concentration of nisin was determined, and its effect against Staphylococcus aureus and Staphylococcus epidermidis biofilms was evaluated. Results obtained by confocal laser microscopy demonstrated morphological changes in the architecture of the structure of biofilms. The main components (polysaccharides, proteins, and extracellular DNA (eDNA)) of the biofilm matrix were determined by spectrophotometry and showed that the formation of staphylococcal biofilms in the presence of nisin results in a less dense matrix structure with modification in its constituents. These results contribute to increase the knowledge of the composition and architecture of the extracellular matrix of biofilms of S. aureus, as well as evidence that the investigation of alternative products to assist in the control and combat of biofilms is a promising strategy.},
}
@article {pmid31454730,
year = {2019},
author = {Zhou, H and Xu, G},
title = {Integrated effects of temperature and COD/N on an up-flow anaerobic filter-biological aerated filter: Performance, biofilm characteristics and microbial community.},
journal = {Bioresource technology},
volume = {293},
number = {},
pages = {122004},
doi = {10.1016/j.biortech.2019.122004},
pmid = {31454730},
issn = {1873-2976},
abstract = {The integrated effects of temperature and COD/N ratio on performance, biofilm characteristics and microbial community in up-flow anaerobic filter-biological aerated filters (UAF-BAFs) were investigated. Results indicated that the UAF-BAF system could achieve excellent COD, NH4+-N and TN removal, in which effluent quality well met the Class 1A standard. Biofilm physicochemical characteristics showed that the biomass, biofilm thickness and extracellular polymeric substance (EPS) content in the UAF-BAFs reduced with the decrease in COD/N ratio, but were enhanced under low temperature. The biofilm structure characterized by CLSM in the UAF-BAFs significantly shifted, which was closely correlated with operational conditions. Sequencing analysis revealed that Proteobacteria, Epsilonbacteraeota, Bacteroidetes and Firmicutes were dominant in the UAFs and the abundance of ammonium oxidizing bacteria (AOB) was responsible for nitrification performance in the BAFs. Functions analysis indicated that amino acid metabolism, carbohydrate metabolism, energy metabolism and lipid metabolism were clearly regulated by parameters changes.},
}
@article {pmid31454717,
year = {2019},
author = {Chen, LH and Li, Y and Qi, Y and Wang, SN and Gao, CQ and Wu, Y},
title = {Evaluation of a pulsed xenon ultraviolet light device for reduction of pathogens with biofilm-forming ability and impact on environmental bioburden in clinical laboratories.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2019.08.026},
pmid = {31454717},
issn = {1873-1597},
abstract = {BACKGROUND: Biofilm-forming organisms can persist on surfaces in hospital clinical laboratories and potentially lead to nosocomial infections. Therefore, effective decontamination procedures are essential for reducing infections. In this study, we investigated an alternative to often ineffective manual cleaning methods, a pulsed xenon ultraviolet (PX-UV) light device. We evaluated PX-UV effect on biofilm formation ability of pathogens and also evaluated PX-UV effectiveness on environmental bioburden in clinical laboratories.<br><br>METHODS: We selected and identified P. aeruginosa PA47, Staphylococcus aureus B1, and K. pnenumoniae CR52 from clinic isolates. Biofilm-forming ability and effectiveness of PX-UV in killing these biofilm forming strains on surfaces was evaluated. A body fluid testing laboratory, microbiology laboratory, and immunology/HIV prescreening laboratory were chosen for testing environmental bioburden. Air samples and high-touch surface specimens in the three laboratories were obtained before and after routine manual cleaning, and after 6 min of PX-UV disinfection. The cultured microbes were then identified with MALDI- TOF-MS.<br><br>RESULTS: We found that P. aeruginosa PA47, Staphylococcus aureus B1, and K. pnenumoniae CR52 were able to form robust biofilms, and that PX-UV significantly reduced colony counts of these strains on all surfaces tested. PX-UV reduced the bioburden of air samples and eliminated bioburden on surfaces. All microbes identified in the clinical laboratories were pathogenic and consisted of cocci, rods, and fungi.<br><br>CONCLUSIONS: The PX-UV device effectively reduced pathogens with biofilm-forming ability on surfaces, and the environmental bioburden was also significantly reduced by PX-UV. PX-UV is a viable option for protecting staff and decreasing rates of laboratory-acquired infections.},
}
@article {pmid31454558,
year = {2019},
author = {Prasath, KG and Sethupathy, S and Pandian, SK},
title = {Proteomic analysis uncovers the modulation of ergosterol, sphingolipid and oxidative stress pathway by myristic acid impeding biofilm and virulence in Candida albicans.},
journal = {Journal of proteomics},
volume = {208},
number = {},
pages = {103503},
doi = {10.1016/j.jprot.2019.103503},
pmid = {31454558},
issn = {1876-7737},
abstract = {Candida albicans, a dimorphic opportunistic fungus is known to form robust biofilm and commonly associated with superficial and life threatening systemic infections. The repertoire of C. albicans infection is comprehensive due to its biofilm mediated virulence and occurrence of resistance against conventional antifungal drugs. Natural bioactive compounds are known for their antivirulence potency against fungi circumventing their resistance. In the present study, antibiofilm and antihyphal efficacies of myristic acid (MA), a major component of Myristica fragrans against C. albicans was assessed. Results of biofilm assays, optical microscopic analyses showed the potent inhibition of biofilm and hyphal formation by MA at 125 μg mL-1. Proteomic analysis revealed the ability of MA to target proteins involved in various virulence pathways such as ergosterol synthesis, sphingolipid metabolism, multidrug resistance and the oxidative stress. The results of gene expression analysis and biochemical assays validated the outcomes of proteomic analysis. This investigation emphasized the potent antibiofilm and virulence inhibitory potentials of MA. Hence, MA could be clinically utilized to control infections caused by C. albicans. BIOLOGICAL SIGNIFICANCE: The conventional antifungal drugs acquire single target pattern by regulating either sterol synthesis or drug efflux pump in C. albicans that ushers drug-resistance. But Myristic acid attenuates C. albicans virulence by negative regulation of proteins involved in sterol synthesis &amp; uptake, sphingolipids and antioxidant activity. In the current study, the multi-target efficacy and the ability to inhibit biofilm and hyphae mediated virulence factors without affecting the cellular metabolism of C. albicans marks myristic acid as a potent anti-candida agent against drug resistant Candida species.},
}
@article {pmid31452954,
year = {2019},
author = {Barkarmo, S and Longhorn, D and Leer, K and Johansson, CB and Stenport, V and Franco-Tabares, S and Kuehne, SA and Sammons, R},
title = {Biofilm formation on polyetheretherketone and titanium surfaces.},
journal = {Clinical and experimental dental research},
volume = {5},
number = {4},
pages = {427-437},
doi = {10.1002/cre2.205},
pmid = {31452954},
issn = {2057-4347},
abstract = {Objective: Polyetheretherketone (PEEK) is a polymer used in devices in orthopedic and dental rehabilitation. The aim of this in vitro study was to compare biofilm formation by a range of important oral bacterial species on PEEK, blasted PEEK, commercially pure titanium (cp-Ti), and titanium-6 aluminium-4 vanadium (Ti6Al4V).<br><br>Material and methods: Coin-shaped samples were manufactured, and the surfaces were characterized using optical interferometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and contact angle measurements. Bacterial species of Streptococcus sanguinis, Streptococcus oralis, Enterococcus faecalis, and Streptococcus gordonii were cultured on the four material surfaces for varying amounts of time. Biofilms were quantified following staining with crystal violet.<br><br>Results: Roughness and contact angle results showed blasted PEEK > PEEK > cp-Ti = Ti6Al4V. There was increased biofilm formation on blasted PEEK by S. sanguinis, S. oralis, and S. gordonii, whereas the bacterial adhesion was similar on PEEK, cp-Ti, and Ti6Al4V. The bacterial growth of E. faecalis was significantly higher on cp-Ti compared with the other three groups.<br><br>Conclusion: The results, taking into consideration the biofilm formation, suggest that PEEK should perform as well as cp-Ti or TiAl6V4 when used as a dental restorative material.},
}
@article {pmid31452924,
year = {2019},
author = {McCall, AD and Pathirana, RU and Prabhakar, A and Cullen, PJ and Edgerton, M},
title = {Candida albicans biofilm development is governed by cooperative attachment and adhesion maintenance proteins.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {21},
doi = {10.1038/s41522-019-0094-5},
pmid = {31452924},
issn = {2055-5008},
support = {F31 DE024346/DE/NIDCR NIH HHS/United States ; R01 DE010641/DE/NIDCR NIH HHS/United States ; R01 DE022720/DE/NIDCR NIH HHS/United States ; },
abstract = {The opportunistic fungal pathogen Candida albicans is capable of adhering to the oral mucosa despite forces created by salivary flow. Although many fungal adhesion proteins have been identified, less is known about the temporal development of cell adhesion and biofilm growth in a flow environment. In this study, we use a flow system with real-time imaging of C. albicans cells as they adhere and grow. Rates of cell attachment and dispersion of C. albicans knockout strains of putative adhesins, transcription factors, and deletions with a hyperfilamentous phenotype were quantified during 18 h of biofilm development. Cell adhesion under flow is a multi-phase process initiated with cell rolling, then an initial firm attachment to the substrate occurs. After attachment, cells enter a growth phase where cells either commit to adherence or disperse. C. albicans Δeap1, Δhwp2, Δhyr1, and Δihd1 cells had significantly reduced initial attachment and subsequent adhesion, while Δals1/Δals3 had no change in initial attachment but reduced adhesion maintenance. WT cells had increased adhesion during the late growth phase when hyphae were more highly expressed. Hyperfilamentous strains had 10-fold higher total biofilm growth, a result of significantly reduced detachment rates, showing that hyphal morphogenesis is important for adhesion maintenance in the developing biofilm. The rate of C. albicans biomass dispersion was most important for determining the density of the mature biomass. Adhesion maintenance was mediated in part by Ywp1, a protein previously thought to regulate dispersion, thus it functions as an adhesion maintenance protein in C. albicans.},
}
@article {pmid31451500,
year = {2019},
author = {Rodríguez-Sevilla, G and Crabbé, A and García-Coca, M and Aguilera-Correa, JJ and Esteban, J and Pérez-Jorge, C},
title = {Antimicrobial treatment provides a competitive advantage to Mycobacterium abscessus in a dual species biofilm with Pseudomonas aeruginosa.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.01547-19},
pmid = {31451500},
issn = {1098-6596},
abstract = {The physiological factors that contribute to Mycobacterium abscessus lung infections remain unclear. We determined if antibiotic treatment targeting a major CF pathogen (i.e. Pseudomonas aeruginosa) could provide the ideal conditions for the establishment of M. abscessus infection. Our data showed that P. aeruginosa inhibits M. abscessus biofilm formation under control conditions, and that antimicrobial therapy selectively targeting P. aeruginosa diminishes this competitive interaction, hereby increasing M. abscessus survival.},
}
@article {pmid31451499,
year = {2019},
author = {Albano, M and Karau, MJ and Greenwood-Quaintance, KE and Osmon, DR and Oravec, CP and Berry, DJ and Abdel, MP and Patel, R},
title = {In vitro Activity of Rifampin, Rifabutin, Rifapentine and Rifaximin Against Planktonic and Biofilm States of Staphylococci Isolated from Periprosthetic Joint Infection.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.00959-19},
pmid = {31451499},
issn = {1098-6596},
abstract = {in vitro activities of rifampin, rifabutin, rifapentine and rifaximin were tested against 200 PJI-associated staphylococci. Seven rifampin-resistant isolates had MICs ≥4 μg/mL. Three isolates had rifampin MICs 0.25-1μg/mL and harbored a Asp471Gly RpoB variant. The remaining isolates had rifampin MICs ≤0.016 μg/mL. Rifampin, rifabutin, rifapentine and rifaximin MBBC50 values for rifampin-susceptible isolates were 8, 1, 2, 4 (S. aureus), and 2, 0.06, 0.25, 0.5 (S. epidermidis) μg/mL, respectively. Non-rifampin rifamycins have promising staphylococcal anti-biofilm activity.},
}
@article {pmid31450779,
year = {2019},
author = {Llamazares, C and Sanz Del Olmo, N and Ortega, P and Gómez, R and Soliveri, J and de la Mata, FJ and García-Gallego, S and Copa-Patiño, JL},
title = {Antibacterial Effect of Carbosilane Metallodendrimers in Planktonic Cells of Gram-Positive and Gram-Negative Bacteria and Staphylococcus aureus Biofilm.},
journal = {Biomolecules},
volume = {9},
number = {9},
pages = {},
doi = {10.3390/biom9090405},
pmid = {31450779},
issn = {2218-273X},
support = {CTQ2017-86224-P//Ministerio de Economía y Competitividad/ ; Consortium IMMUNOTHERCAN B2017/BMD-3733//Comunidad de Madrid/ ; Consortium NANODENDMED-II B2017/BMD-3703//Comunidad de Madrid/ ; Research Talent Attraction Program 2017-T2/IND-5243//Comunidad de Madrid/ ; Project SBPLY/17/180501/000358//Junta de Comunidades de Castilla-La Mancha/ ; CIBER-BBN//Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina/ ; },
abstract = {Antibiotic resistance is currently one of the main threats to public health security. Biofilm formation is a resistance mechanism that is responsible for most human bacterial infections and requires new and effective therapeutic approaches, such as those provided by nanotechnology. In this work, the antibacterial effect of carbosilane metallodendrimers with different metals (copper(II) and ruthenium(II)), ligands (chloride and nitrate) and generations (generation 0, 1 and 2) has been studied using planktonic Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Furthermore, the ability of the metallodendrimers to avoid the formation of S. aureus biofilms was also evaluated. The results showed a promising biocide activity in both types of planktonic bacteria, especially for first-generation dendrimers, which arises from the metal complexation to the dendrimer. Cu(II) metallodendrimers require lower concentration than Ru(II) counterpart to inhibit the production of S. aureus biofilms, but none produce hemolysis at the inhibitory concentrations and can be safely used as antibacterial agents. In particular, the first-generation Cu(II) metallodendrimer with nitrate ligands displayed the most promising properties to continue with further studies in both planktonic cells and biofilms.},
}
@article {pmid31450696,
year = {2019},
author = {Smolobochkin, A and Gazizov, A and Sazykina, M and Akylbekov, N and Chugunova, E and Sazykin, I and Gildebrant, A and Voronina, J and Burilov, A and Karchava, S and Klimova, M and Voloshina, A and Sapunova, A and Klimanova, E and Sashenkova, T and Allayarova, U and Balakina, A and Mishchenko, D},
title = {Synthesis of Novel 2-(Het)arylpyrrolidine Derivatives and Evaluation of Their Anticancer and Anti-Biofilm Activity.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {17},
pages = {},
doi = {10.3390/molecules24173086},
pmid = {31450696},
issn = {1420-3049},
abstract = {A library of novel 2-(het)arylpyrrolidine-1-carboxamides were obtained via a modular approach based on the intramolecular cyclization/Mannich-type reaction of N-(4,4-diethoxybutyl)ureas. Their anti-cancer activities both in vitro and in vivo were tested. The in vitro activity of some compounds towards M-Hela tumor cell lines was twice that of the reference drug tamoxifen, whereas cytotoxicity towards normal Chang liver cell did not exceed the tamoxifen toxicity. In vivo studies showed that the number of surviving animals on day 60 of observation was up to 83% and increased life span (ILS) was up to 447%. Additionally, some pyrrolidine-1-carboxamides possessing a benzofuroxan moiety obtained were found to effectively suppress bacterial biofilm growth. Thus, these compounds are promising candidates for further development both as anti-cancer and anti-bacterial agents.},
}
@article {pmid31450579,
year = {2019},
author = {Wijesundara, NM and Rupasinghe, HPV},
title = {Herbal Tea for the Management of Pharyngitis: Inhibition of Streptococcus pyogenes Growth and Biofilm Formation by Herbal Infusions.},
journal = {Biomedicines},
volume = {7},
number = {3},
pages = {},
doi = {10.3390/biomedicines7030063},
pmid = {31450579},
issn = {2227-9059},
support = {CRDPJ 448052//Natural Sciences and Engineering Research Council of Canada/ ; },
abstract = {Herbal teas are becoming popular as functional beverages due to their various health promotional properties. This study aimed at assessing 13 hot water infusions (HWIs) from different herbs against streptococcal pharyngitis (strep throat). Licorice root exhibited the lowest minimum inhibitory concentrations (MIC) of 1.56 mg/mL, followed by barberry root, thyme, and oregano flowering shoots, with a MIC of 3.13 mg/mL. At their respective minimum bactericidal concentrations (MBC), licorice showed the bactericidal effect on S. pyogenes within 12 h after exposure while others need 24 h for a similar outcome. The HWIs exhibited inhibitory activity on biofilm formation, ranging from 1.56 to 6.25 mg/mL, which confirmed by ruptured cells or clusters of dead cell debris observed in scanning electron microscope (SEM). Overall, non-toxic concentrations of efficacious HWIs from licorice root, barberry root, thyme, and oregano flowering shoots may provide potential sources for developing herbal teas or biomedicine for the management of S. pyogenes infections.},
}
@article {pmid31450202,
year = {2019},
author = {Sinharoy, A and Baskaran, D and Pakshirajan, K},
title = {A novel carbon monoxide fed moving bed biofilm reactor for sulfate rich wastewater treatment.},
journal = {Journal of environmental management},
volume = {249},
number = {},
pages = {109402},
doi = {10.1016/j.jenvman.2019.109402},
pmid = {31450202},
issn = {1095-8630},
abstract = {In this study, a moving bed biofilm reactor was used for biodesulfuruization using CO as the sole carbon substrate. The effect of hydraulic retention time (HRT), sulfate loading rate and CO loading rate on sulfate and CO removal was examined. At 72, 48 and 24 h HRT, the sulfate removal was 93.5%, 91.9% and 80.1%, respectively. An increase in the sulfate loading reduced the sulfate reduction efficiency, which, however, was improved by increasing the CO flow rate into the MBBR. Best results in terms of sulfate reduction (>80%) were obtained for low inlet sulfate and high CO loading conditions. The CO utilization was very high at 85% throughout the study, except during the last phase of the continuous bioreactor operation it was around 70%. An artificial neural network based model was successfully developed and optimized to accurately predict the bioreactor performance in terms of both sulfate reduction and CO utilization. Overall, this study showed an excellent potential of the moving bed biofilm bioreactor for efficient sulfate reduction even under high loading conditions.},
}
@article {pmid31448272,
year = {2019},
author = {Saggu, SK and Jha, G and Mishra, PC},
title = {Enzymatic Degradation of Biofilm by Metalloprotease From Microbacterium sp. SKS10.},
journal = {Frontiers in bioengineering and biotechnology},
volume = {7},
number = {},
pages = {192},
doi = {10.3389/fbioe.2019.00192},
pmid = {31448272},
issn = {2296-4185},
abstract = {Enzymes have replaced or decreased usage of toxic chemicals for industrial and medical applications leading toward sustainable chemistry. In this study, we report purification and characterization of a biofilm degrading protease secreted by Microbacterium sp. SKS10. The protease was identified as a metalloprotease, Peptidase M16 using mass spectrometry. It showed optimum activity at 60°C, pH 12 and retained its activity in the presence of various salts and organic solvents. The enzyme was able to degrade biofilms efficiently at enzyme concentration lower than other known enzymes such as papain, trypsin and α-amylase. The presence of this protease increased the accessibility of antibiotics inside the biofilm, and was found to be non-cytotoxic toward human epidermoid carcinoma cells (A431) at the effective concentration for biofilm degradation. Thus, this protease may serve as an effective tool for management of biofilms.},
}
@article {pmid31448253,
year = {2019},
author = {Ciccozzi, M and Cella, E and Lai, A and De Florio, L and Antonelli, F and Fogolari, M and Di Matteo, FM and Pizzicannella, M and Colombo, B and Dicuonzo, G and Angeletti, S},
title = {Phylogenetic Analysis of Multi-Drug Resistant Klebsiella pneumoniae Strains From Duodenoscope Biofilm: Microbiological Surveillance and Reprocessing Improvements for Infection Prevention.},
journal = {Frontiers in public health},
volume = {7},
number = {},
pages = {219},
doi = {10.3389/fpubh.2019.00219},
pmid = {31448253},
issn = {2296-2565},
abstract = {Duodenoscopes have been described as potential vehicles of patient-to-patient transmission of multi-drug resistant organisms. Carbapenem-resistant Enterobacteriaceae duodenoscope related infections have been described by the Center for Disease Control and the US Food and Drug Administration consequently to outbreaks occurring in the United States. These evidences suggested that improved microbiological surveillance and endoscope design optimization could represent valid tools to improve infection control. At this aim, in this study an example of duodenoscope microbiological surveillance and reprocessing improvement analyzing strains component of bacterial biofilm by phylogenetic analysis has been proposed. From September 2016 to December 2017, duodenoscope instruments were subjected to microbial surveillance by post-reprocessing cultures of liquid collected by internal channels of instruments after injection and aspiration cycles and membrane filtration. During surveillance seventeen Klebsiella pneumoniae, of which 10/17 (58.8%) MDR and KPC strains were collected from duodenoscope instruments plus one MDR Klebsiella pneumoniae strain from the rectal swab performed before ERCP procedure in an inpatient. The surveillance allowed evidencing potential failure of reprocessing procedure and performing consequent reprocessing improvements including the contaminated instruments quarantine until their negativity. Phylogenetic analysis of whole genome sequence of duodenoscope strains plus inpatients MDR strains, showed intermixing between duodenoscopes and inpatients, as evidenced by minimum spanning tree and time-scale Maximum Clade Credibility tree. In minimum spanning tree, three groups have been evidenced. Group I including Klebsiella pneumoniae strains, isolated from inpatients before microbiological surveillance adoption; group II including intermixed Klebsiella pneumoniae strains isolated from inpatients and Klebsiella pneumoniae strains isolated from duedonoscopes and group III including Klebsiella pneumoniae strains exclusively from duedonoscope instruments. In the Maximum Credibility Tree, a statistically supported cluster including two Klebsiella pneumoniae strains from duedonoscope instruments and one strains isolated from an inpatient was showed. From the first microbiologic surveillance performed on September 2016 and after the reprocessing improvement adoption, none MDR or susceptible Klebsiella pneumoniae strain was isolated in the following surveillance periods. In conclusion, these results should encourage hospital board to perform microbiological surveillance of duodenoscopes as well as of patients, by rectal swabs culture, and rapid molecular testing for antimicrobial resistance before any endoscopic invasive procedure.},
}
@article {pmid31447791,
year = {2019},
author = {Kesy, K and Oberbeckmann, S and Kreikemeyer, B and Labrenz, M},
title = {Spatial Environmental Heterogeneity Determines Young Biofilm Assemblages on Microplastics in Baltic Sea Mesocosms.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1665},
doi = {10.3389/fmicb.2019.01665},
pmid = {31447791},
issn = {1664-302X},
abstract = {Microplastics in aquatic environments provide novel habitats for surface-colonizing microorganisms. Given the continuing debate on whether substrate-specific properties or environmental factors prevail in shaping biofilm assemblages on microplastics, we examined the influence of substrate vs. spatial factors in the development of bacterial assemblages on polyethylene (PE), polystyrene (PS), wood, and seston and in the free-living fraction. Further, the selective colonization of microplastics by potential pathogens was investigated because among the bacterial species found in microplastic-associated biofilms are potentially pathogenic Vibrio spp. Due to their persistence and great dispersal potential, microplastics could act as vectors for these potential pathogens and for biofilm assemblages in general. Incubation experiments with these substrates were conducted for 7 days during a summer cruise along the eastern Baltic Sea coastline in waters covering a salinity gradient of 4.5-9 PSU. Bacterial assemblages were analyzed using 16S rRNA-gene amplicon sequencing, distance-based redundancy analyses, and the linear discriminant analysis effect size method to identify taxa that were significantly more abundant on the plastics. The results showed that the sample type was the most important factor structuring bacterial assemblages overall. Surface properties were less significant in differentiating attached biofilms on PE, PS, and wood; instead, environmental factors, mainly salinity, prevailed. A potential role for inorganic-nutrient limitations in surface-specific attachment was identified as well. Alphaproteobacteria (Sphingomonadaceae, Devosiaceae, and Rhodobacteraceae) and Gammaproteobacteria (Alteromonadaceae and Pseudomonas) were distinctive for the PE- and PS-associated biofilms. Vibrio was more abundant on the PE and PS biofilms than on seston, but its abundances were highest on wood and positively correlated with salinity. These results corroborate earlier findings that microplastics constitute a habitat for biofilm-forming microorganisms distinct from seston, but less from wood. In contrast to earlier reports of low Vibrio numbers on microplastics, these results also suggest that vibrios are early colonizers of surfaces in general. Spatial as well as temporal dynamics should therefore be considered when assessing the potential of microplastics to serve as vectors for bacterial assemblages and putative pathogens, as these parameters are major drivers of biofilm diversity.},
}
@article {pmid31447460,
year = {2019},
author = {Wu, S and Liu, Y and Zhang, H and Lei, L},
title = {A new transformation method with nanographene oxides of antisense carrying yycG RNA improved antibacterial properties on methicillin-resistant Staphylococcus aureus biofilm.},
journal = {The Journal of veterinary medical science},
volume = {},
number = {},
pages = {},
doi = {10.1292/jvms.19-0216},
pmid = {31447460},
issn = {1347-7439},
abstract = {Staphylococcus aureus have the potential to opportunistically cause infectious diseases. The aim of this study was to determine the antimicrobial effects of novel graphene oxide (GO)-polyethylenimine (PEI)-based antisense yycG (ASyycG) on the inhibition of methicillin-resistant S. aureus (MRSA) biofilm formation. In current study, a novel GO-PEI-based recombinant ASyycG vector transformation strategy was developed to produce ASyycG. The mechanical features including zeta-potential and particle size distributions were evaluated by: (1) GO; (2) GO-PEI; and (3) GO-PEI-ASyycG. The recombinant ASyycG vector was transformed into MRSA cells, and the expression levels of the yycF/G and icaADB genes were determined and compared by quantitative real-time PCR (qPCR) assays. The recombinant ASyycG plasmids were subsequently modified with a gene encoding enhanced green fluorescent protein (ASyycG-eGFP) as a reporter gene, and the transformation efficiency was assessed by the fluorescence intensity. The biofilm biomass and bacterial viability of the MRSA strains were evaluated by crystal violet assay, colony-forming unit assays and confocal laser scanning microscopy. The results showed that the Z-average sizes of GO-PEI-ASyycG were much larger than those of GO or GO-PEI. The GO-PEI-based strategy significantly increased the efficiency of ASyycG transformation. The GO-PEI-ASyycG-transformed MRSA strain had the lowest expression levels of the biofilm formation-associated genes. Furthermore, GO-PEI-ASyycG suppressed biofilm aggregation and improved bactericidal effects on the MRSA after 24 hr of biofilm establishment. Our findings demonstrated that GO-PEI based antisense yycG RNA will be an effective method for management of MRSA infections.},
}
@article {pmid31445309,
year = {2019},
author = {Wu, X and Pan, J and Li, M and Li, Y and Bartlam, M and Wang, Y},
title = {Selective enrichment of bacterial pathogens by microplastic biofilm.},
journal = {Water research},
volume = {165},
number = {},
pages = {114979},
doi = {10.1016/j.watres.2019.114979},
pmid = {31445309},
issn = {1879-2448},
abstract = {Microplastics have been found to be ubiquitous in freshwater ecosystems, providing a novel substrate for biofilm formation. Here, we incubated biofilm on microplastics and two natural substrates (rock and leaf) under a controlled environment to investigate the differences of microbial community structure, antibiotic resistance gene (ARG) profiles, and ARG microbial hosts between biofilms on three types of substrates. Results from high-throughput sequencing of 16S rRNA gene revealed that microplastic biofilm had a distinctive community structure. Network analyses suggested that microplastic biofilm possessed the highest node connected community, but with lower average path length, network diameter and modularity compared with biofilm on two natural particles. Metagenomic analyses further revealed microplastic biofilm with broad-spectrum and distinctive resistome. Specifically, according to taxonomic annotation of ARG microbial hosts, two opportunisitic human pathogens (Pseudomonas monteilii, Pseudomonas mendocina) and one plant pathogen (Pseudomonas syringae) were detected only in the microplastic biofilm, but not in biofilms formed on natural substrates. Our findings suggest that microplastic is a novel microbial niche and may serve as a vector for ARGs and pathogens to new environment in river water, generating freshwater environmental risk and exerting adverse impacts on human health.},
}
@article {pmid31444121,
year = {2019},
author = {Cui, MH and Sangeetha, T and Gao, L and Wang, AJ},
title = {Efficient azo dye wastewater treatment in a hybrid anaerobic reactor with a built-in integrated bioelectrochemical system and an aerobic biofilm reactor: Evaluation of the combined forms and reflux ratio.},
journal = {Bioresource technology},
volume = {},
number = {},
pages = {122001},
doi = {10.1016/j.biortech.2019.122001},
pmid = {31444121},
issn = {1873-2976},
abstract = {A combined process that consisted of a hybrid anaerobic reactor (HAR) with an integral bioelectrochemical system and aerobic biofilm reactor (ABFR) was established for simulated azo dye wastewater treatment (domestic wastewater containing dye acid orange 7). The split combination form that separated HAR and ABFR into two individual reactors recorded a decolorization efficiency of 81.23 ± 0.12%, which was about 8% higher than that HAR and ABFR were stacked together into a single up-flow reactor. Implementation of reflux improved the decolorization and chemical oxygen demand (COD) removal in both the processes. Decolorization efficiency achieved 97.52 ± 0.66% in split process at a reflux ratio of 1 and the COD was 89 ± 2 mg/L in the final effluent. Further increasing the reflux ratio to 3 did not have any significance in treatment performance of the reactors. This study comprehensively revealed the influence of combination forms and reflux ratio on the performance of combined process.},
}
@article {pmid31444120,
year = {2019},
author = {Sun, S and Liu, J and Zhang, M and He, S},
title = {Simultaneous improving nitrogen removal and decreasing greenhouse gas emission with biofilm carriers addition in ecological floating bed.},
journal = {Bioresource technology},
volume = {},
number = {},
pages = {121944},
doi = {10.1016/j.biortech.2019.121944},
pmid = {31444120},
issn = {1873-2976},
abstract = {Ecological floating bed (EFB) is a green technology for treatment of micro-polluted wastewater. However, its nitrogen removal efficiency is still unsatisfactory. In this study, two EFBs with additional carbon source were established to explore biofilm carriers addition on nitrogen removal and greenhouse gas (GHG) emissions at different C/N ratios and temperatures. Results showed that biofilm carriers addition increased nitrification and nitrogen removal efficiencies in EFB, and more denitrifying and nitrifying bacteria were attached to the biofilm carriers. Higher N2O and CH4 emissions were found in control EFB without biofilm carriers addition which was consistent with higher nitrite accumulation. In addition, high-throughput sequencing analysis revealed that adding biofilm carriers could improve the richness and diversity of biological communities. For EFB with additional carbon source treating secondary effluent, adding biofilm carrier can obtain higher TN removal efficiency and lower greenhouse gas emission.},
}
@article {pmid31443467,
year = {2019},
author = {Arul Selvaraj, RC and Rajendran, M and Nagaiah, HP},
title = {Re-Potentiation of β-Lactam Antibiotic by Synergistic Combination with Biogenic Copper Oxide Nanocubes against Biofilm Forming Multidrug-Resistant Bacteria.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {17},
pages = {},
doi = {10.3390/molecules24173055},
pmid = {31443467},
issn = {1420-3049},
support = {(Ref: NM/NS/01/2015 (G) dated 30 May,2016//DST, Nano Mission, India/ ; },
abstract = {Biofilm-associated tissue and device infection is a major threat to therapy. The present work aims to potentiate β-lactam antibiotics with biologically synthesized copper oxide nanoparticles. The synergistic combination of amoxyclav with copper oxide nanoparticles was investigated by checkerboard assay and time-kill assay against bacteria isolated from a burn wound and a urinary catheter. The control of biofilm formation and extracellular polymeric substance production by the synergistic combination was quantified in well plate assay. The effect of copper oxide nanoparticles on the viability of human dermal fibroblasts was evaluated. The minimum inhibitory concentration and minimum bactericidal concentration of amoxyclav were 70 μg/mL and 140 μg/mL, respectively, against Proteus mirabilis and 50 μg/mL and 100 μg/mL, respectively, against Staphylococcus aureus. The synergistic combination of amoxyclav with copper oxide nanoparticles reduced the minimum inhibitory concentration of amoxyclav by 16-fold against P. mirabilis and 32-fold against S. aureus. Above 17.5 μg/mL, amoxyclav exhibited additive activity with copper oxide nanoparticles against P. mirabilis. The time-kill assay showed the efficacy of the synergistic combination on the complete inhibition of P. mirabilis and S. aureus within 20 h and 24 h, respectively, whereas amoxyclav and copper oxide nanoparticles did not inhibit P. mirabilis and S. aureus until 48 h. The synergistic combination of amoxyclav with copper oxide nanoparticles significantly reduced the biofilm formed by P. mirabilis and S. aureus by 85% and 93%, respectively. The concentration of proteins, carbohydrates, and DNA in extracellular polymeric substances of the biofilm was significantly reduced by the synergistic combination of amoxyclav and copper oxide nanoparticles. The fibroblast cells cultured in the presence of copper oxide nanoparticles showed normal morphology with 99.47% viability. No cytopathic effect was observed. Thus, the study demonstrated the re-potentiation of amoxyclav by copper oxide nanoparticles.},
}
@article {pmid31443115,
year = {2019},
author = {Wroe, JA and Johnson, CT and García, AJ},
title = {Bacteriophage delivering hydrogels reduce biofilm formation in vitro and infection in vivo.},
journal = {Journal of biomedical materials research. Part A},
volume = {},
number = {},
pages = {},
doi = {10.1002/jbm.a.36790},
pmid = {31443115},
issn = {1552-4965},
support = {F30AR069472//National Institutes of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health/ ; R01AR062920//National Institutes of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health/ ; //The Georgia Tech President's Undergraduate Research Award (PURA)/ ; },
abstract = {Implanted orthopedic devices become infected more frequently than any other implanted surgical device. These infections can be extremely costly and result in significant patient morbidity. Current treatment options typically involve the long term, systemic administration of a combination of antibiotics, often followed by implant removal. Here we engineered an injectable hydrogel capable of encapsulating Pseudomonas aeruginosa bacteriophage and delivering active phage to the site of bone infections. Bacteriophage retain their bacteriolytic activity after encapsulation and release from the hydrogel, and their rate of release from the hydrogel can be controlled by gel formulation. Bacteriophage-encapsulating hydrogels effectively kill their host bacteria in both planktonic and biofilm phenotypes in vitro without influencing the metabolic activity of human mesenchymal stromal cells. Bacteriophage-encapsulating hydrogels were used to treat murine radial segmental defects infected with P. aeruginosa. The hydrogels achieved a 4.7-fold reduction in live P. aeruginosa counts at the infection site compared to bacteriophage-free hydrogels at 7 days postimplantation. These results support the development of bacteriophage-delivering hydrogels to treat local bone infections.},
}
@article {pmid31442835,
year = {2019},
author = {Wu, X and Cen, Q and Addy, M and Zheng, H and Luo, S and Liu, Y and Cheng, Y and Zhou, W and Chen, P and Ruan, R},
title = {A novel algal biofilm photobioreactor for efficient hog manure wastewater utilization and treatment.},
journal = {Bioresource technology},
volume = {292},
number = {},
pages = {121925},
doi = {10.1016/j.biortech.2019.121925},
pmid = {31442835},
issn = {1873-2976},
abstract = {This study developed a high-efficiency algal biofilm photobioreactor for microalgae by designing a special array of curtain membrane components. This paper also discusses the growth and nutrient composition of Chlorella vulgaris, and hog manure wastewater utilization and purification. It was found that after about 5 days of culture, the biomass of C. vulgaris on the membrane could reach as high as 7.37 g/m2 and the algae were easily harvested by mechanical scraping. The lipid content of C. vulgaris on the membrane structure was 10.17% while the lipid content of the algae in suspension was 14.29%. The light intensity showed a significant effect on the fatty acid composition. The C. vulgaris grew very well, and achieved deep purification of the hog manure wastewater; the COD, TP, TN, and NH4+-N removal rates reached 95.67%, 64.40%, 69.55%, and 91.24%, respectively.},
}
@article {pmid31440218,
year = {2019},
author = {Todhanakasem, T and Salangsing, OL and Koomphongse, P and Kaewket, S and Kanokratana, P and Champreda, V},
title = {Zymomonas mobilis Biofilm Reactor for Ethanol Production Using Rice Straw Hydrolysate Under Continuous and Repeated Batch Processes.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1777},
doi = {10.3389/fmicb.2019.01777},
pmid = {31440218},
issn = {1664-302X},
abstract = {Plastic composited corn silk was developed as a biotic/abiotic carrier for Zymomonas mobilis biofilm formation for the purpose of ethanol production. Furthermore, we explored the use of rice straw hydrolysate as substrate in both multistage continuous culture and repeated batch processes and compared the ethanol production efficiency by two strains of Z. mobilis. Biofilm formed by bacterial strains Z. mobilis ZM4 and TISTR551 were detected, and its proficiencies were compared under various conditions by scanning electron microscopy (SEM) and crystal violet assays. The greatest biofilm formed by both strains was found on day five after the inoculation. Z. mobilis strain ZM4 grown in repeated batch biofilm reactors produced higher yields of ethanol than TISTR551 grown under the same conditions, while TISTR551 produced higher yields of ethanol in the multistage continuous process. The yields were highly maintained, with no significant differences (p < 0.05) among the three consecutive repeated batches. These experiments highlight exciting uses for agricultural byproducts in the production of ethanol using Z. mobilis biofilm reactors.},
}
@article {pmid31440064,
year = {2019},
author = {Shariati, A and Asadian, E and Fallah, F and Azimi, T and Hashemi, A and Yasbolaghi Sharahi, J and Taati Moghadam, M},
title = {Evaluation of Nano-curcumin effects on expression levels of virulence genes and biofilm production of multidrug-resistant Pseudomonas aeruginosa isolated from burn wound infection in Tehran, Iran.},
journal = {Infection and drug resistance},
volume = {12},
number = {},
pages = {2223-2235},
doi = {10.2147/IDR.S213200},
pmid = {31440064},
issn = {1178-6973},
abstract = {Background: P. aeruginosa is considered as one of the most important pathogens, and high antibiotic resistance to P. aeruginosa has become an alarming concern. This study attempts to further improve curcumin solubility and stability by producing the involved nanoparticle and investigate the effect of this nanoparticle on those virulence genes of P. aeruginosa in pathogenicity and biofilm formation.<br><br>Methods: In this study, the curcumin nanoparticles were synthesized and characterized, and the antibacterial and antibiofilm effects of Nano-curcumin and curcumin were investigated by microdilution broth and microtiter plate, respectively. In addition, cytotoxic effect of Nano-curcumin on human epithelial cell lines (A549) was determined. The effects of Nano-curcumin on P. aeruginosa virulence genes, mexD, mexB, and mexT (efflux pumps), lecA (adhesion), nfxB (negative regulator of MexCD-OprJ), and rsmZ (biofilm formation) were determined using real-time quantitative PCR.<br><br>Results: Synthesized Nano-curcumins were soluble in water, which inhibited the growth of multidrug-resistant (MDR) P. aeruginosa at 128 µg/mL, whereas it was inhibited at 256 µg/mL for soluble curcumin in DMSO. Sub-inhibitory concentrations of Nano-curcumin reduced biofilm formation and, at 64 μg/mL, disrupted 58% of the established bacterial biofilms. In addition, curcumin nanoparticle downregulated the transcription of virulence genes except nfxB and exerted no cytotoxic effect on human epithelial cell lines (A549).<br><br>Conclusions: Results suggest that Nano-curcumin could be potentially used to reduce P. aeruginosa virulence and biofilm. However, in vivo studies with respect to an animal model are necessary to validate these results.},
}
@article {pmid31439876,
year = {2019},
author = {Champion, AE and Catanzaro, KCF and Bandara, AB and Inzana, TJ},
title = {Formation of the Francisella tularensis Biofilm is Affected by Cell Surface Glycosylation, Growth Medium, and a Glucan Exopolysaccharide.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {12252},
doi = {10.1038/s41598-019-48697-x},
pmid = {31439876},
issn = {2045-2322},
support = {DE-FG02-93ER20097//U.S. Department of Energy (DOE)/ ; },
abstract = {Biofilms are matrix-associated communities that enable bacteria to colonise environments unsuitable for free-living bacteria. The facultative intracellular pathogen Francisella tularensis can persist in water, amoebae, and arthropods, as well as within mammalian macrophages. F. tularensis Types A and B form poor biofilms, but F. tularensis mutants lacking lipopolysaccharide O-antigen, O-antigen capsule, and capsule-like complex formed up to 15-fold more biofilm than fully glycosylated cells. The Type B live vaccine strain was also 50% less capable of initiating surface attachment than mutants deficient in O-antigen and capsule-like complex. However, the growth medium of all strains tested also influenced the formation of biofilm, which contained a novel exopolysaccharide consisting of an amylose-like glucan. In addition, the surface polysaccharide composition of the bacterium affected the protein:DNA:polysaccharide composition of the biofilm matrix. In contrast, F. novicida attached to surfaces more efficiently and made a more robust biofilm than Type A or B strains, but loss of O-antigen or capsule-like complex did not significantly affect F. novicida biofilm formation. These results indicated that suppression of surface polysaccharides may promote biofilm formation by F. tularensis Types A and B. Whether biofilm formation enhances survival of F. tularensis in aquatic or other environmental niches has yet to be determined.},
}
@article {pmid31439670,
year = {2019},
author = {Kaus, K and Biester, A and Chupp, E and Lu, J and Visudharomn, C and Olson, R},
title = {The 1.9 Å crystal structure of the extracellular matrix protein Bap1 from Vibrio cholerae provides insights into bacterial biofilm adhesion.},
journal = {The Journal of biological chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1074/jbc.RA119.008335},
pmid = {31439670},
issn = {1083-351X},
abstract = {Growth of the cholera bacterium Vibrio cholerae in a biofilm community contributes to both its pathogenicity and survival in aquatic environmental niches. The major components of V. cholerae biofilms include Vibriopolysaccharide (VPS) and the extracellular matrix proteins RbmA, RbmC, and Bap1. To further elucidate the previously observed overlapping roles of Bap1 and RbmC in biofilm architecture and surface attachment, here we investigated the structural and functional properties of Bap1. Soluble expression of Bap1 was possible only after the removal of an internal 57-amino-acid-long hydrophobic insertion sequence. The crystal structure of Bap1 at 1.9 Å resolution revealed a two-domain assembly made up of an eight-bladed β-propeller interrupted by a β-prism domain. The structure also revealed metal-binding sites within canonical calcium blade motifs, which appear to have structural rather than functional roles. Contrary to results previously observed with RbmC, the Bap1 β-prism domain did not exhibit affinity for complex N-glycans, suggesting an altered role of this domain in biofilm-surface adhesion. Native polyacrylamide gel shift analysis did suggest that Bap1 exhibits lectin activity with a preference for anionic and/or linear polysaccharides. Our results suggest a model for V. cholerae biofilms in which Bap1 and RbmC play dominant but differing adhesive roles in biofilms, allowing bacterial attachment to diverse environmental or host surfaces.},
}
@article {pmid31438836,
year = {2019},
author = {Pires, MEE and Parreira, AG and Silva, TNL and Colares, HC and da Silva, JA and de Magalhães, JT and Galdino, AS and Gonçalves, DB and Granjeiro, JM and Granjeiro, PA},
title = {Recent patents on impact of lipopeptide on the biofilm formation onto titanium and stainless steel surfaces.},
journal = {Recent patents on biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.2174/1872208313666190822150323},
pmid = {31438836},
issn = {2212-4012},
abstract = {BACKGROUND: Numerous causes of infection in arthroplasties are related to biofilm formation on implant surfaces. In order to circumvent this problem, new alternatives to prevent bacterial adhesion biosurfactants-based are emerging due to low toxicity, biodegradability and antimicrobial activity of several biosurfactants. We revised all patents relating to biosurfactants of applicability in orthopedic implants.<br><br>METHODS: This work aims to evaluate the capability of a lipopeptide produced by Bacillus subtilis ATCC 19659 isolates acting as inhibitors of the adhesion of Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 29213 onto titanium and stainless steel surfaces and its antimicrobial activity.<br><br>RESULTS: The adhesion of the strains to the stainless-steel surface was higher than that of titanium. Preconditioning of titanium and stainless-steel surfaces with 10 mg mL-1 lipopeptide reduced the adhesion of E. coli by up to 93% and the adhesion of S. aureus by up to 99.9%, suggesting the strong potential of lipopeptides in the control of orthopedic infections. The minimal inhibitory concentration and minimum bactericidal concentration were 10 and 240 μg mL-1 for E. coli and S. aureus, respectively.<br><br>CONCLUSION: The lipopeptide produced by Bacillus subtilis ATCC 19659 presented high biotechnological application in human health against orthopedic implants infections.},
}
@article {pmid31438656,
year = {2019},
author = {Skowron, K and Wałecka-Zacharska, E and Grudlewska, K and Gajewski, P and Wiktorczyk, N and Wietlicka-Piszcz, M and Dudek, A and Skowron, KJ and Gospodarek-Komkowska, E},
title = {Disinfectant Susceptibility of Biofilm Formed by Listeria monocytogenes under Selected Environmental Conditions.},
journal = {Microorganisms},
volume = {7},
number = {9},
pages = {},
doi = {10.3390/microorganisms7090280},
pmid = {31438656},
issn = {2076-2607},
abstract = {Listeria monocytogenes is a one of the most important food-borne pathogens. Its ability to form biofilm contributes to increased resistance to disinfectants and inefficient disinfection, posing a serious threat for the food industry, and in the end the consumer. The aim of this study was the comparison of the biofilm formation ability of L. monocytogenes strains on stainless steel, under different environmental conditions (temperature, pH, NaCl concentration, nutrients availability), and the assessment of biofilm susceptibility to disinfectants. The bactericidal activity of four disinfectants in two concentrations (100% and 50% of working solution) against biofilm was conducted on four clinical strains, four strains isolated from food and one reference strain ATCC 19111. It was found that biofilm susceptibility to disinfectants was influenced by environmental conditions. Biofilm susceptibility correlated with the decrease of temperature, pH, nutrients availability and salinity of the environment. The least sensitive to disinfectants was biofilm produced at pH = 4 (the bacterial number ranged from 0.25 log CFU × cm-2 to 1.72 log CFU × cm-2) whereas the most sensitive was biofilm produced at pH = 9 (5.16 log CFU × cm-2 to 7.84 log CFU × cm-2). Quatosept was the most effective disinfectant, regardless of the conditions. In conclusion, biofilm susceptibility to disinfectants is strain-dependent and is affected by environmental conditions.},
}
@article {pmid31438629,
year = {2019},
author = {Lorenzo, D},
title = {Chloramphenicol Resurrected: A Journey from Antibiotic Resistance in Eye Infections to Biofilm and Ocular Microbiota.},
journal = {Microorganisms},
volume = {7},
number = {9},
pages = {},
doi = {10.3390/microorganisms7090278},
pmid = {31438629},
issn = {2076-2607},
abstract = {The advent of multidrug resistance among pathogenic bacteria is devastating the worth of antibiotics and changing the way of their administration, as well as the approach to use new or old drugs. The crisis of antimicrobial resistance is also due to the unavailability of newer drugs, attributable to exigent regulatory requirements and reduced financial inducements. The emerging resistance to antibiotics worldwide has led to renewed interest in old drugs that have fallen into disuse because of toxic side effects. Thus, comprehensive efforts are needed to minimize the pace of resistance by studying emergent microorganisms and optimize the use of old antimicrobial agents able to maintain their profile of susceptibility. Chloramphenicol is experiencing its renaissance because it is widely used in the treatment and prevention of superficial eye infections due to its broad spectrum of activity and other useful antimicrobial peculiarities, such as the antibiofilm properties. Concerns have been raised in the past for the risk of aplastic anemia when chloramphenicol is given intravenously. Chloramphenicol seems suitable to be used as topical eye formulation for the limited rate of resistance compared to fluoroquinolones, for its scarce induction of bacterial resistance and antibiofilm activity, and for the hypothetical low impact on ocular microbiota disturbance. Further in-vitro and in vivo studies on pharmacodynamics properties of ocular formulation of chloramphenicol, as well as its real impact against biofilm and the ocular microbiota, need to be better addressed in the near future.},
}
@article {pmid31437576,
year = {2019},
author = {Khan, F and Jeong, MC and Park, SK and Kim, SK and Kim, YM},
title = {Contribution of chitooligosaccharides to biofilm formation, antibiotics resistance and disinfectants tolerance of Listeria monocytogenes.},
journal = {Microbial pathogenesis},
volume = {136},
number = {},
pages = {103673},
doi = {10.1016/j.micpath.2019.103673},
pmid = {31437576},
issn = {1096-1208},
abstract = {Listeria monocytogenes is a food-borne pathogen present in various environmental reservoirs. It exhibits resistance and tolerance to antibiotics and sanitizing agents used in several food processing industries. It has been reported that L. monocytogenes chitinase can catalyze hydrolysis of chitin polymeric carbohydrate present in the environment and act as a virulence factor that support its survival in mammalian host cells. By taking advantage of chitinase, L. monocytogenes has both saprophytic and pathogenic lifestyles in the soil and the living host, respectively. The objective of the present study was to determine the involvement of chitin degradation products such as chitooligosaccharides (COS) in biofilm formation of L. monocytogenes. Results showed that different concentrations of COS with various molecular weight enhanced biofilm formation of L. monocytogenes. Such enhancement in biofilm formation contributed to the development of antibiotics resistance and disinfectants tolerance of cells present in the biofilm. The present article also described diverse roles of chitin, chitinase, and degradation of chitin and chitin-like substrates in saprophytic and pathogenic lifestyles of L. monocytogenes. This study offers a new direction for further exploration of the mechanisms of pathogenesis caused by L. monocytogenes.},
}
@article {pmid31437202,
year = {2019},
author = {Romero-Lastra, P and Sánchez, MC and Llama-Palacios, A and Figuero, E and Herrera, D and Sanz, M},
title = {Gene expression of Porphyromonas gingivalis ATCC 33277 when growing in an in vitro multispecies biofilm.},
journal = {PloS one},
volume = {14},
number = {8},
pages = {e0221234},
doi = {10.1371/journal.pone.0221234},
pmid = {31437202},
issn = {1932-6203},
abstract = {BACKGROUND AND OBJECTIVE: Porphyromonas gingivalis, an oral microorganism residing in the subgingival biofilm, may exert diverse pathogenicity depending on the presence of specific virulence factors, but its gene expression has not been completely established. This investigation aims to compare the transcriptomic profile of this pathogen when growing within an in vitro multispecies biofilm or in a planktonic state.<br><br>MATERIALS AND METHODS: P. gingivalis ATCC 33277 was grown in anaerobiosis within multi-well culture plates at 37°C under two conditions: (a) planktonic samples (no hydroxyapatite discs) or (b) within a multispecies-biofilm containing Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans deposited on hydroxyapatite discs. Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM) combined with Fluorescence In Situ Hybridization (FISH) were used to verify the formation of the biofilm and the presence of P. gingivalis. Total RNA was extracted from both the multispecies biofilm and planktonic samples, then purified and, with the use of a microarray, its differential gene expression was analyzed. A linear model was used for determining the differentially expressed genes using a filtering criterion of two-fold change (up or down) and a significance p-value of <0.05. Differential expression was confirmed by Reverse Transcription-quantitative Polymerase Chain Reaction (RT-qPCR).<br><br>RESULTS: SEM verified the development of the multispecies biofilm and FISH confirmed the incorporation of P. gingivalis. The microarray demonstrated that, when growing within the multispecies biofilm, 19.1% of P. gingivalis genes were significantly and differentially expressed (165 genes were up-regulated and 200 down-regulated), compared with planktonic growth. These genes were mainly involved in functions related to the oxidative stress, cell envelope, transposons and metabolism. The results of the microarray were confirmed by RT-qPCR.<br><br>CONCLUSION: Significant transcriptional changes occurred in P. gingivalis when growing in a multispecies biofilm compared to planktonic state.},
}
@article {pmid31437081,
year = {2019},
author = {Sun, R and Xu, Y and Wu, Y and Tang, J and Esquivel-Elizondo, S and Kerr, PG and Staddon, PL and Liu, J},
title = {Functional sustainability of nutrient accumulation by periphytic biofilm under temperature fluctuations.},
journal = {Environmental technology},
volume = {},
number = {},
pages = {1-10},
doi = {10.1080/09593330.2019.1659422},
pmid = {31437081},
issn = {1479-487X},
abstract = {Temperature can fluctuate widely between different seasons, and this may greatly impact many biological processes. However, little is known about its influence on the functioning of benthic microbial communities. Here we investigated the nutrient accumulation capability of periphytic biofilm under temperature fluctuations (17-35°C). Periphytic biofilm maintained the same nutrient accumulation capacity after experiencing the 'warming-hot-cooling' temperature fluctuation under both lab and outdoor conditions as those without temperature disturbance. In response to temperature increase, both community composition and species richness changed greatly and the increase in biodiversity was identified as being the underlying mechanism boosting the sustainable function in nutrient accumulation, indicating zero net effects of community changes. These findings provide insights into the underlying mechanisms of how benthic microbial communities adapt to temperature fluctuations to maintain nutrient accumulation capacity and elucidate that periphytic biofilm plays important roles in influencing nutrient cycling in aquatic ecosystems under temperature changes such as seasonal fluctuations.},
}
@article {pmid31435968,
year = {2019},
author = {Cho, P and Boost, MV},
title = {Evaluation of prevention and disruption of biofilm in contact lens cases.},
journal = {Ophthalmic &amp; physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists)},
volume = {},
number = {},
pages = {},
doi = {10.1111/opo.12635},
pmid = {31435968},
issn = {1475-1313},
abstract = {PURPOSE: The presence of biofilm in the lens case has been shown to be a risk factor for contamination of lenses and consequently microbial keratitis. This study aimed to evaluate effectiveness of solutions for rigid contact lenses in prevention and disruption of biofilm in lens cases and methods for biofilm detection.<br><br>METHOD: This study adopted a stepwise approach to evaluate effectiveness of four rigid lens disinfecting solutions against biofilm. These included two polyhexamethylene bigiuanide (PHMB) solutions and a chlorhexidine/PHMB-based solution, as well as a novel povidone-iodine formulation. The presence of biofilm following exposure to the solutions was assessed using both crystal violet (CV) staining and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) viability assay, taking into account the effect of lens case design. Three lens case designs, conventional flat, large bucket type, and cylindrical cases, were investigated for the ability to trap stain and allow biofilm formation.<br><br>RESULTS: Considerable differences were noted between solutions in their ability to prevent and disrupt biofilm (p < 0.001). Lens case design greatly influenced optical density (OD) measurements even in negative controls, as cylindrical cases trapped more stain, increasing OD readings. Correcting for this factor reduced variations, but could not differentiate between residues and biofilm. MTT assay revealed that both povidone-iodine and chlorhexidine-containing solutions could effectively kill > 95% of organisms, whilst PHMB-based solutions were less effective with up to 55% of staphylococci and 41% of Pseudomonas surviving at 24 h.<br><br>CONCLUSION: Biofilm can rapidly form in lens cases and may not be killed by disinfecting solutions. Of the solutions tested, none were able to prevent biofilm formation or disrupt established biofilm, but those containing chlorhexidine or povidone iodine were able to penetrate the biofilm and kill organisms. Assessment of biofilm by CV assay may be confounded by lens case design. Whilst CV assay can demonstrate presence of biofilm, this technique should be accompanied by viability assay to determine bactericidal activity.},
}
@article {pmid31432881,
year = {2019},
author = {Ran, HH and Cheng, X and Bao, YW and Hua, XW and Gao, G and Zhang, X and Jiang, YW and Zhu, YX and Wu, FG},
title = {Multifunctional quaternized carbon dots with enhanced biofilm penetration and eradication efficiencies.},
journal = {Journal of materials chemistry. B},
volume = {7},
number = {33},
pages = {5104-5114},
doi = {10.1039/c9tb00681h},
pmid = {31432881},
issn = {2050-7518},
abstract = {Biofilm formation can lead to the treatment failure of persistent bacterial infections. Although a variety of antibacterial agents have been developed, the restricted drug penetration and the embedded bacteria's potentiated recalcitrance to these agents synergistically lead to the unsatisfactory anti-biofilm effect. Herein, we report the applications of metal-free quaternized carbon dots (CDs) in imaging and eliminating bacterial biofilms. The CDs prepared by the solvothermal treatment of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (abbreviated as Si-QAC) and glycerol possess ultrasmall size (ca. 3.3 ± 0.4 nm) and strong positively charged (zeta potential: ca. +33.1 ± 2.5 mV) surfaces with long alkyl chain-linked quaternary ammonium groups. The small size of the CDs endows them with the penetration ability into the interior of Gram-negative and Gram-positive bacterial biofilms, which enables excellent fluorescence imaging of the biofilms. Due to the different surfaces of the two types of bacteria, the positively charged CDs selectively interact with the more negatively charged Gram-positive bacteria via electrostatic and hydrophobic interactions, which inactivates the Gram-positive bacteria and ultimately eradicates the Gram-positive bacterial biofilms. In addition, we synthesize a new type of quaternized CDs without long alkyl chains (termed TTPAC CDs), and validate that the long alkyl chains potentiate the hydrophobic adhesion between CDs and Gram-positive bacteria. Meanwhile, the crystal violet staining results reveal that the cationic CDs inhibit the formation of Gram-positive bacterial biofilms. Collectively, our work highlights the feasibility of using cationic and ultrasmall metal-free CDs to eliminate and inhibit Gram-positive bacterial biofilms, which represents a highly effective strategy to cope with refractory biofilm-associated infections.},
}
@article {pmid31432051,
year = {2019},
author = {Kuper, NK and Hollanders, ACC and Dekkers, EAM and Maske, TT and Huysmans, MDNJM and Cenci, MS},
title = {Aging Reduces the Anticaries Effect of Antibacterial Adhesive - An In Vitro Biofilm Study.},
journal = {The journal of adhesive dentistry},
volume = {21},
number = {4},
pages = {365-372},
doi = {10.3290/j.jad.a42999},
pmid = {31432051},
issn = {1757-9988},
abstract = {PURPOSE: This in vitro study investigated whether aging different restorative materials influences secondary caries development using a short-term in vitro biofilm model, hypothesizing that the antibacterial adhesive employed may lose its effect over time.<br><br>MATERIALS AND METHODS: Sixty enamel-dentin blocks were divided into 6 groups with n = 10 per group. The groups were restored with three different restorative materials, of which each sample contained an artificial gap: composite with conventional adhesive (CCA; negative control), composite with an antibacterial adhesive (CAA), and amalgam (A; positive control). Half of the groups were prepared fresh and half of the groups were submitted to an aging protocol consisting of water storage, thermocycling, storage in human saliva, and storage in 0.9% saline solution. All specimens were subjected to an intermittent 1% sucrose biofilm model for 20 days to create artificial caries lesions. Lesion progression in the enamel and dentin next to the different materials was measured as lesion depth (LD) and mineral loss (ML), using transverse wavelength independent microradiography (T-WIM). Regression analysis was used to evaluate the effect of aging on LD and ML per restorative material, corrected for gap size.<br><br>RESULTS: In the amalgam group, aging led to shallower lesions and less mineral loss. Fresh amalgam samples showed an average lesion depth of 156.65 ± 39.18 µm at wall dentin locations. Aged amalgam samples had an average lesion depth of 73.42 ± 73.50 µm. Fresh CAA samples showed lower average surface mineral loss values (9104 ± 2631 µm•vol%) than did fresh CCA samples (13166 ± 4769 µm•vol%). After aging, this effect was absent, and the average mineral loss in the CAA group was 13382 ± 5586 µm•vol%, while in the CCA group it was 15518 ± 9283 µm•vol%.<br><br>CONCLUSION: Aging can influence secondary caries development either positively or negatively depending on the kind of restorative material. Antibacterial adhesives may lose their effectiveness over time.},
}
@article {pmid31430670,
year = {2019},
author = {Li, H and Wang, B and Deng, S and Dai, J and Shao, S},
title = {Oxygen-containing functional groups on bioelectrode surface enhance expression of c-type cytochromes in biofilm and boost extracellular electron transfer.},
journal = {Bioresource technology},
volume = {292},
number = {},
pages = {121995},
doi = {10.1016/j.biortech.2019.121995},
pmid = {31430670},
issn = {1873-2976},
abstract = {Introducing oxygen-containing functional groups is a common and convenient method to increase the hydrophilicity of bioelectrodes. In this study, the effect of oxygen-containing functional groups on biofilm was systematically studied to understand how the electron transfer between electrochemically active bacteria (EAB) and bioelectrode was boosted. After electrolysis pretreatment in sulfuric and nitric acid mixture, the oxygen content of the carbon fiber brushes increased from 4.6% to 30.9%. Comparing with the control, the maximum power density increased by 27.7%, while the anode resistance decreased by 21.8%, because charge transfer resistance significantly reduced. The analysis results showed that the content of c-type cytochromes (c-Cyts) in the EAB biofilm was four times higher than that in the control, while the biomass just slightly increased and the bacteria community was similar with that of the control. These findings suggested that the fundamental reason for the enhanced extracellular electron transfer between EAB and electrode was the increased c-Cyts.},
}
@article {pmid31430343,
year = {2019},
author = {Giacomucci, S and Cros, CD and Perron, X and Mathieu-Denoncourt, A and Duperthuy, M},
title = {Flagella-dependent inhibition of biofilm formation by sub-inhibitory concentration of polymyxin B in Vibrio cholerae.},
journal = {PloS one},
volume = {14},
number = {8},
pages = {e0221431},
doi = {10.1371/journal.pone.0221431},
pmid = {31430343},
issn = {1932-6203},
abstract = {Biofilm formation is a common strategy used by bacteria in order to survive and persist in the environment. In Vibrio cholerae (V. cholerae), a Gram-negative pathogen responsible for the cholera disease, biofilm-like aggregates are important for the pathogenesis and disease transmission. Biofilm formation is initiated by the attachment of the bacteria to a surface, followed by maturation stages involving the formation of a biofilm matrix. In V. cholerae, flagella are essential for the initial step of biofilm formation, allowing the bacteria to swim and to detect a surface. In this study, we explored the effect of polymyxin B (PmB), a cationic bacterial antimicrobial peptide, on biofilm formation in pathogenic V. cholerae strains belonging to the O1 and O139 serotypes. We found that sub-inhibitory concentration of PmB induces a reduction of the biofilm formation by V. cholerae O1 and O139. Experiment on preformed biofilm demonstrated that the biofilm formation inhibition occurs at the initial step of biofilm formation, where the flagella are essential. We further characterize the effect of PmB on V. cholerae flagellation. Our results demonstrate that the flagellin expression is not reduced in presence of sub-inhibitory concentration of PmB. However, a decrease of the abundance of flagellin associated with the bacterial cells together with an increase in the secretome was observed. Electron microscopy observations also suggest that the abundance of aflagellated bacteria increases upon PmB supplementation. Finally, in agreement with the effect on the flagellation, a reduction of the bacterial motility is observed. Altogether, our results suggest that the PmB affect V. cholerae flagella resulting in a decrease of the motility and a compromised ability to form biofilm.},
}
@article {pmid31430121,
year = {2019},
author = {Wang, S and Breslawec, AP and Alvarez, E and Tyrlik, M and Li, C and Poulin, MB},
title = {Differential Recognition of Deacetylated PNAG Oligosaccharides by a Biofilm Degrading Glycosidase.},
journal = {ACS chemical biology},
volume = {},
number = {},
pages = {},
doi = {10.1021/acschembio.9b00467},
pmid = {31430121},
issn = {1554-8937},
abstract = {Exopolysaccharides consisting of partially de-N-acetylated poly-β-d-(1→6)-N-acetyl-glucosamine (dPNAG) are key structural components of the biofilm extracellular polymeric substance of both Gram-positive and Gram-negative human pathogens. De-N-acetylation is required for the proper assembly and function of dPNAG in biofilm development suggesting that different patterns of deacetylation may be preferentially recognized by proteins that interact with dPNAG, such as Dispersin B (DspB). The enzymatic degradation of dPNAG by the Aggregatibacter actinomycetemcomitans native β-hexosaminidase enzyme DspB plays a role in biofilm dispersal. To test the role of substrate de-N-acetylation on substrate recognition by DspB, we applied an efficient preactivation-based one-pot glycosylation approach to prepare a panel of dPNAG trisaccharide analogs with defined acetylation patterns. These analogs served as effective DspB substrates, and the rate of hydrolysis was dependent on the specific substrate de-N-acetylation pattern, with glucosamine (GlcN) located +2 from the site of cleavage being preferentially hydrolyzed. The product distributions support a primarily exoglycosidic cleavage activity following a substrate assisted cleavage mechanism, with the exception of substrates containing a nonreducing GlcN that were cleaved endo leading to the exclusive formation of a nonreducing disaccharide product. These observations provide critical insight into the substrate specificity of dPNAG specific glycosidase that can help guide their design as biocatalysts.},
}
@article {pmid31429746,
year = {2019},
author = {Funk, B and Kirmayer, D and Sahar-Heft, S and Gati, I and Friedman, M and Steinberg, D},
title = {Efficacy and potential use of novel sustained release fillers as intracanal medicaments against Enterococcus faecalis biofilm in vitro.},
journal = {BMC oral health},
volume = {19},
number = {1},
pages = {190},
doi = {10.1186/s12903-019-0879-1},
pmid = {31429746},
issn = {1472-6831},
abstract = {BACKGROUND: Enterococcus faecalis is a bacterium frequently isolated after failed root canal therapy. This study analyzed the antibacterial and antibiofilm effects in vitro of sustained-release fillers (SRF) containing cetylpyridinium chloride (CPC) against vancomycin resistant E. faecalis.<br><br>METHODS: First, the solidification capability was tested by introducing liquid SRF into phosphate buffered saline, followed by 30 s of vortexing. The antimicrobial effects of SRF-CPC against static monospecies biofilms were analyzed with a metabolic assay. Inhibition of biofilm formation was tested by exposing daily refreshed E. faecalis suspensions to SRF-CPC for 9 weeks. To evaluate the effects of SRF-CPC against preformed biofilms, biofilms were grown for 1, 3 and 7 days, and then treated with SRF-CPC for 24 h. Biofilm kill time was tested by applying SRF-CPC to a 3-day-old biofilm and measuring its viability at different time points. All experiments were compared to Placebo SRFs and to untreated control biofilms. Data were analyzed with two-way ANOVA followed by Tukey's test. Results were considered significant at P < 0.05.<br><br>RESULTS: The liquid SRF solidified within seconds and no structural changes were observed after 30 s of vortexing at maximum speed. SRF-CPC inhibited E. faecalis biofilm formation for 7 weeks and significantly reduced its viability in weeks 8 and 9. Mature biofilms grown for 1, 3 and 7 days were destructed by SRF-CPC in less than 24 h. Fifty percent of a 3-day-old biofilm was destructed in 2 h and complete destruction occurred in less than 12 h. (P < 0.05 in all cases, compared to SRII-Placebo).<br><br>CONCLUSIONS: SRF-CPC's physical properties and long-lasting anti-biofilm effects make it a promising coadjuvant medication for endodontic therapy.},
}
@article {pmid31429088,
year = {2019},
author = {Brodersen, KE and Koren, K and Revsbech, NP and Kühl, M},
title = {Strong leaf surface basification and CO2 limitation of seagrass induced by epiphytic biofilm microenvironments.},
journal = {Plant, cell &amp; environment},
volume = {},
number = {},
pages = {},
doi = {10.1111/pce.13645},
pmid = {31429088},
issn = {1365-3040},
abstract = {Coastal eutrophication is a growing problem worldwide, leading to increased epiphyte overgrowth of seagrass leaves. Yet, little is known about how epiphytes affect key biogeochemical conditions and processes in the seagrass phyllosphere. We used electrochemical microsensors to measure microgradients of O2 , pH, and CO2 at the bare and epiphyte-covered leaf surface of seagrass (Zostera marina L.) to determine effects of epiphytes on the leaf chemical microenvironment. Epiphytes result in extreme daily fluctuations in pH, O2 and inorganic carbon concentrations at the seagrass leaf surface severely hampering the plant's performance. In light, leaf epiphyte biofilms and their diffusive boundary layer (DBL) lead to strong basification, markedly reducing the CO2 and HCO3- availability at the leaf surface, leading to reduced photosynthetic efficiency as a result of carbon limitation and enhanced photorespiration. With epiphytes, leaf surface pH increased to >10, thereby exceeding final pH levels (~9.62) and CO2 compensation points for active photosynthesis. In darkness, epiphyte biofilms resulted in increased CO2 and hypoxia at the leaf surface. Epiphytes can lead to severe carbon limitation in seagrasses owing to strong phyllosphere basification leading to CO2 depletion and costly, yet limiting, HCO3- utilization, increasing the risk of plant starvation.},
}
@article {pmid31428077,
year = {2019},
author = {Cirri, E and De Decker, S and Bilcke, G and Werner, M and Osuna-Cruz, CM and De Veylder, L and Vandepoele, K and Werz, O and Vyverman, W and Pohnert, G},
title = {Associated Bacteria Affect Sexual Reproduction by Altering Gene Expression and Metabolic Processes in a Biofilm Inhabiting Diatom.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1790},
doi = {10.3389/fmicb.2019.01790},
pmid = {31428077},
issn = {1664-302X},
abstract = {Diatoms are unicellular algae with a fundamental role in global biogeochemical cycles as major primary producers at the base of aquatic food webs. In recent years, chemical communication between diatoms and associated bacteria has emerged as a key factor in diatom ecology, spurred by conceptual and technological advancements to study the mechanisms underlying these interactions. Here, we use a combination of physiological, transcriptomic, and metabolomic approaches to study the influence of naturally co-existing bacteria, Maribacter sp. and Roseovarius sp., on the sexual reproduction of the biofilm inhabiting marine pennate diatom Seminavis robusta. While Maribacter sp. severely reduces the reproductive success of S. robusta cultures, Roseovarius sp. slightly enhances it. Contrary to our expectation, we demonstrate that the effect of the bacterial exudates is not caused by altered cell-cycle regulation prior to the switch to meiosis. Instead, Maribacter sp. exudates cause a reduced production of diproline, the sexual attraction pheromone of S. robusta. Transcriptomic analyses show that this is likely an indirect consequence of altered intracellular metabolic fluxes in the diatom, especially those related to amino acid biosynthesis, oxidative stress response, and biosynthesis of defense molecules. This study provides the first insights into the influence of bacteria on diatom sexual reproduction and adds a new dimension to the complexity of a still understudied phenomenon in natural diatom populations.},
}
@article {pmid31428070,
year = {2019},
author = {Chen, T and Liu, N and Ren, P and Xi, X and Yang, L and Sun, W and Yu, B and Ying, H and Ouyang, P and Liu, D and Chen, Y},
title = {Efficient Biofilm-Based Fermentation Strategies for L-Threonine Production by Escherichia coli.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1773},
doi = {10.3389/fmicb.2019.01773},
pmid = {31428070},
issn = {1664-302X},
abstract = {Biofilms provide cells favorable growth conditions, which have been exploited in industrial biotechnological processes. However, industrial application of the biofilm has not yet been reported in Escherichia coli, one of the most important platform strains, though the biofilm has been extensively studied for pathogenic reasons. Here, we engineered E. coli by overexpressing the fimH gene, which successfully enhanced its biofilm formation under industrial aerobic cultivation conditions. Subsequently, a biofilm-based immobilized fermentation strategy was developed. L-threonine production was increased from 10.5 to 14.1 g/L during batch fermentations and further to 17.5 g/L during continuous (repeated-batch) fermentations with enhanced productivities. Molecular basis for the enhanced biofilm formation and L-threonine biosynthesis was also studied by transcriptome analysis. This study goes beyond the conventional research focusing on pathogenic aspects of E. coli biofilm and represents a successful application case of engineered E. coli biofilm to industrial processes.},
}
@article {pmid31427961,
year = {2019},
author = {Oves, M and Rauf, MA and Hussain, A and Qari, HA and Khan, AAP and Muhammad, P and Rehman, MT and Alajmi, MF and Ismail, IIM},
title = {Antibacterial Silver Nanomaterial Synthesis From Mesoflavibacter zeaxanthinifaciens and Targeting Biofilm Formation.},
journal = {Frontiers in pharmacology},
volume = {10},
number = {},
pages = {801},
doi = {10.3389/fphar.2019.00801},
pmid = {31427961},
issn = {1663-9812},
abstract = {Considering the significance of biological and eco-friendly nanomaterials, in the present study, we have synthesized silver nanoparticles from the exopolysaccharide of recently recovered bacterial strain CEES51 from the Red Sea coastal area of Jeddah, Saudi Arabia. 16S ribosomal RNA gene sequencing was used to characterize the isolated bacteria, and it was identified as Mesoflavibacter zeaxanthinifaciens and assigned an accession number MH707257.1 GenBank. The bacterial strain is an excellent exopolysaccharide producer and survived at hypersaline (30%) and high-temperature (50°C) conditions. The bacterial exopolysaccharides were employed for the fabrication of silver nanoparticles at room temperature. UV-visible spectrophotometer optimized the synthesized nanoparticles, and their size was determined by Nanophox particle size analyzer and dynamic light scattering. Additionally, the X-ray powder diffraction and Fourier-transform infrared spectroscopy studies also approved its crystalline nature and the involvement of organic functional groups in their formation. The synthesized nanomaterials were tested for their antibacterial and antibiofilm properties against pathogenic microorganisms Bacillus subtilis and methicillin-resistant Staphylococcus aureus. The antimicrobial property showed time, and dose-dependent response with a maximum of zone inhibition was observed at around 22 and 18 mm at a dose of 50 µg/well against B. subtilis and S. aureus and a minimum inhibitory concentration of 8 and 10 µg/ml, respectively. Furthermore, the synthesized silver nanoparticles possessed a substantial antibiofilm property and were also found to be biocompatible as depicted by red blood cell lysis assay and their interaction with peripheral blood mononuclear cells and human embryonic kidney 293 cells. Therefore, Mesoflavibacter zeaxanthinifaciens is found to be an excellent source for exopolysaccharide synthesis that assists in the silver nanoparticle production.},
}
@article {pmid31427659,
year = {2019},
author = {Kindler, O and Pulkkinen, O and Cherstvy, AG and Metzler, R},
title = {Burst statistics in an early biofilm quorum sensing model: the role of spatial colony-growth heterogeneity.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {12077},
doi = {10.1038/s41598-019-48525-2},
pmid = {31427659},
issn = {2045-2322},
support = {Humboldt Polish Honorary Research Fellowship//Fundacja na rzecz Nauki Polskiej (Foundation for Polish Science)/ ; ME 1535/7-1//Deutsche Forschungsgemeinschaft (German Research Foundation)/ ; },
abstract = {Quorum-sensing bacteria in a growing colony of cells send out signalling molecules (so-called &quot;autoinducers&quot;) and themselves sense the autoinducer concentration in their vicinity. Once-due to increased local cell density inside a &quot;cluster&quot; of the growing colony-the concentration of autoinducers exceeds a threshold value, cells in this clusters get &quot;induced&quot; into a communal, multi-cell biofilm-forming mode in a cluster-wide burst event. We analyse quantitatively the influence of spatial disorder, the local heterogeneity of the spatial distribution of cells in the colony, and additional physical parameters such as the autoinducer signal range on the induction dynamics of the cell colony. Spatial inhomogeneity with higher local cell concentrations in clusters leads to earlier but more localised induction events, while homogeneous distributions lead to comparatively delayed but more concerted induction of the cell colony, and, thus, a behaviour close to the mean-field dynamics. We quantify the induction dynamics with quantifiers such as the time series of induction events and burst sizes, the grouping into induction families, and the mean autoinducer concentration levels. Consequences for different scenarios of biofilm growth are discussed, providing possible cues for biofilm control in both health care and biotechnology.},
}
@article {pmid31427301,
year = {2019},
author = {Bilal, H and Bergen, PJ and Kim, TH and Chung, SE and Peleg, AY and Oliver, A and Nation, RL and Landersdorfer, CB},
title = {Synergistic meropenem-tobramycin combination dosage regimens against clinical hypermutable Pseudomonas aeruginosa at simulated epithelial lining fluid concentrations in a dynamic biofilm model.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.01293-19},
pmid = {31427301},
issn = {1098-6596},
abstract = {Exacerbations of chronic Pseudomonas aeruginosa infections are a major treatment challenge in cystic fibrosis due to biofilm formation and hypermutation. We aimed to evaluate different dosage regimens of meropenem and tobramycin in monotherapies and combination against hypermutable carbapenem-resistant P. aeruginosa A hypermutable P. aeruginosa isolate (MICmeropenem and MICtobramycin 8 mg/L) was investigated in the dynamic CDC biofilm reactor over 120 h. Regimens were meropenem as standard (2 g 8-hourly, 30% epithelial lining fluid (ELF) penetration) and continuous infusion (CI, 6 g/day, 30% and 60% ELF penetration), and tobramycin 10 mg/kg 24-hourly (50% ELF penetration). The time-courses of total and less-susceptible bacteria and MICs were determined and antibiotic concentrations quantified by LC-MS/MS. All monotherapies failed with substantial regrowth of planktonic (>6 log10 CFU/mL) and biofilm (≥6 log10 CFU/cm2) bacteria. Except for meropenem CI (60% ELF penetration) all monotherapies amplified less-susceptible planktonic and biofilm bacteria by 120 h. The meropenem standard regimen with tobramycin caused initial killing followed by considerable regrowth with resistance (MICmeropenem 64 mg/L, MICtobramycin 32 mg/L) for planktonic and biofilm bacteria. The combination containing the meropenem CI, at both levels of ELF penetration, synergistically suppressed regrowth of total planktonic bacteria and resistance of planktonic and biofilm bacteria. The combination with meropenem CI at 60% ELF penetration in addition synergistically suppressed regrowth of total biofilm bacteria. Standard regimens of meropenem and tobramycin were ineffective against planktonic and biofilm bacteria. The combination with meropenem CI exhibited enhanced bacterial killing and resistance suppression of carbapenem-resistant hypermutable P. aeruginosa.},
}
@article {pmid31426832,
year = {2019},
author = {Bujold, AR and Lani, NR and Sanz, MG},
title = {Strain-to-strain variation of Rhodococcus equi growth and biofilm formation in vitro.},
journal = {BMC research notes},
volume = {12},
number = {1},
pages = {519},
doi = {10.1186/s13104-019-4560-1},
pmid = {31426832},
issn = {1756-0500},
abstract = {OBJECTIVE: Rhodococcus equi is an opportunistic pathogen that causes disease worldwide in young foals and immunocompromised humans. The interactions of R. equi with the host immune system have been described; however, most studies have been conducted using a few well-characterized strains. Because biological differences between R. equi strains are not well characterized, it is unknown if experimental results will replicate when different strains are used. Therefore, our objective was to compare the growth and biofilm formation of low-passage-rate clinical isolates of R. equi to higher-passage-rate, commonly studied isolates to determine whether strain-to-strain variation exists.<br><br>RESULTS: Twelve strains were used: 103+, ATCC 33701, UKVDL206 103S harboring a GFP-expressing plasmid, a plasmid-cured 33701 (higher-passage-rate) and seven low-passage clinical isolates. Generation time in liquid revealed fast, moderate-fast, moderate-slow, and slow-growing isolates. The higher-passage-rate isolates were among the moderate-slow growing strains. A strain's rate of growth did not correspond to its ability to form biofilm nor to its colony size on solid media. Based on our results, care should be taken not to extrapolate in vitro work that may be conducted using different R. equi strains. Further work is needed to evaluate the effect that the observed differences may have on experimental results.},
}
@article {pmid31424553,
year = {2019},
author = {Soares, A and Alexandre, K and Lamoureux, F and Lemée, L and Caron, F and Pestel-Caron, M and Etienne, M},
title = {Efficacy of a ciprofloxacin/amikacin combination against planktonic and biofilm cultures of susceptible and low-level resistant Pseudomonas aeruginosa.},
journal = {The Journal of antimicrobial chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1093/jac/dkz355},
pmid = {31424553},
issn = {1460-2091},
abstract = {BACKGROUND: Eradicating bacterial biofilm without mechanical dispersion remains a challenge. Combination therapy has been suggested as a suitable strategy to eradicate biofilm.<br><br>OBJECTIVES: To evaluate the efficacy of a ciprofloxacin/amikacin combination in a model of in vitro Pseudomonas aeruginosa biofilm.<br><br>METHODS: The antibacterial activity of ciprofloxacin and amikacin (alone, in combination and successively) was evaluated by planktonic and biofilm time-kill assays against five P. aeruginosa strains: PAO1, a WT clinical strain and three clinical strains overexpressing the efflux pumps MexAB-OprM (AB), MexXY-OprM (XY) and MexCD-OprJ (CD), respectively. Amikacin MIC was 16 mg/L for XY and ciprofloxacin MIC was 0.5 mg/L for CD. The other strains were fully susceptible to ciprofloxacin and amikacin. The numbers of total and resistant cells were determined.<br><br>RESULTS: In planktonic cultures, regrowth of high-level resistant mutants was observed when CD was exposed to ciprofloxacin alone and XY to amikacin alone. Eradication was obtained with ciprofloxacin or amikacin in the other strains, or with the combination in XY and CD strains. In biofilm, bactericidal reduction after 8 h followed by a mean 4 log10 cfu/mL plateau in all strains and for all regimens was noticed. No regrowth of resistant mutants was observed whatever the antibiotic regimen. The bacterial reduction obtained with a second antibiotic used simultaneously or consecutively was not significant.<br><br>CONCLUSIONS: The ciprofloxacin/amikacin combination prevented the emergence of resistant mutants in low-level resistant strains in planktonic cultures. Biofilm persister cells were not eradicated, either with monotherapy or with the combination.},
}
@article {pmid31423363,
year = {2019},
author = {Payette, G and Geoffroy, V and Martineau, C and Villemur, R},
title = {Dynamics of a methanol-fed marine denitrifying biofilm: 1-Impact of environmental changes on the denitrification and the co-occurrence of Methylophaga nitratireducenticrescens and Hyphomicrobium nitrativorans.},
journal = {PeerJ},
volume = {7},
number = {},
pages = {e7497},
doi = {10.7717/peerj.7497},
pmid = {31423363},
issn = {2167-8359},
abstract = {Background: The biofilm of a methanol-fed denitrification system that treated a marine effluent is composed of multi-species microorganisms, among which Hyphomicrobium nitrativorans strain NL23 and Methylophaga nitratireducenticrescens strain JAM1 are the principal bacteria involved in the denitrifying activities. Here, we report the capacity of the denitrifying biofilm to sustain environmental changes, and the impact of these changes on the co-occurrence of H. nitrativorans and M. nitratireducenticrescens.<br><br>Methods: In a first set of assays, the original biofilm (OB) was cultivated in an artificial seawater (ASW) medium under anoxic conditions to colonize new carriers. The new formed biofilm was then subjected to short exposures (1-5 days) of a range of NaCl, methanol, nitrate (NO3-) and nitrite (NO2-) concentrations, and to different pHs and temperatures. In a second set of assays, the OB was cultivated in ASW medium for five weeks with (i) a range of NaCl concentrations, (ii) four combinations of NO3-/methanol concentrations and temperatures, (iii) NO2-, and (iv) under oxic conditions. Finally, the OB was cultivated for five weeks in the commercial Instant Ocean (IO) seawater. The growth of the biofilm and the dynamics of NO3- and NO2- were determined. The levels of M. nitratireducenticrescens and H. nitrativorans were measured by qPCR.<br><br>Results: In the first set of assays, the biofilm cultures had the capacity to sustain denitrifying activities in most of the tested conditions. Inhibition occurred when they were exposed to high pH (10) or to high methanol concentration (1.5%). In the second set of assays, the highest specific denitrification rates occurred with the biofilm cultures cultivated at 64.3 mM NO3- and 0.45% methanol, and at 30 °C. Poor biofilm development occurred with the biofilm cultures cultivated at 5% and 8% NaCl. In all biofilm cultures cultivated in ASW at 2.75% NaCl, H. nitrativorans strain NL23 decreased by three orders of magnitude in concentrations compared to that found in OB. This decrease coincided with the increase of the same magnitude of a subpopulation of M. nitratireducenticrescens (strain GP59 as representative). In the biofilm cultures cultivated at low NaCl concentrations (0% to 1.0%), persistence of H. nitrativorans strain NL23 was observed, with the gradual increase in concentrations of M. nitratireducenticrescens strain GP59. High levels of H. nitrativorans strain NL23 were found in the IO biofilm cultures. The concentrations of M. nitratireducenticrescens strain JAM1 were lower in most of the biofilms cultures than in OB.<br><br>Conclusions: These results demonstrate the plasticity of the marine methylotrophic denitrifying biofilm in adapting to different environmental changes. The NaCl concentration is a crucial factor in the dynamics of H. nitrativorans strain NL23, for which growth was impaired above 1% NaCl in the ASW-based biofilm cultures in favor of M. nitratireducenticrescens strain GP59.},
}
@article {pmid31423359,
year = {2019},
author = {Villemur, R and Payette, G and Geoffroy, V and Mauffrey, F and Martineau, C},
title = {Dynamics of a methanol-fed marine denitrifying biofilm: 2-impact of environmental changes on the microbial community.},
journal = {PeerJ},
volume = {7},
number = {},
pages = {e7467},
doi = {10.7717/peerj.7467},
pmid = {31423359},
issn = {2167-8359},
abstract = {Background: The biofilm of a methanol-fed, marine denitrification system is composed of a multi-species microbial community, among which Hyphomicrobium nitrativorans and Methylophaga nitratireducenticrescens are the principal bacteria involved in the denitrifying activities. To assess its resilience to environmental changes, the biofilm was cultivated in artificial seawater (ASW) under anoxic conditions and exposed to a range of specific environmental conditions. We previously reported the impact of these changes on the denitrifying activities and the co-occurrence of H. nitrativorans strain NL23 and M. nitratireducenticrescens in the biofilm cultures. Here, we report the impact of these changes on the dynamics of the overall microbial community of the denitrifying biofilm.<br><br>Methods: The original biofilm (OB) taken from the denitrification system was cultivated in ASW under anoxic conditions with a range of NaCl concentrations, and with four combinations of nitrate/methanol concentrations and temperatures. The OB was also cultivated in the commercial Instant Ocean seawater (IO). The bacterial diversity of the biofilm cultures and the OB was determined by 16S ribosomal RNA gene sequences. Culture approach was used to isolate other denitrifying bacteria from the biofilm cultures. The metatranscriptomes of selected biofilm cultures were derived, along with the transcriptomes of planktonic pure cultures of H. nitrativorans strain NL23 and M. nitratireducenticrescens strain GP59.<br><br>Results: High proportions of M. nitratireducenticrescens occurred in the biofilm cultures. H. nitrativorans strain NL23 was found in high proportion in the OB, but was absent in the biofilm cultures cultivated in the ASW medium at 2.75% NaCl. It was found however in low proportions in the biofilm cultures cultivated in the ASW medium at 0-1% NaCl and in the IO biofilm cultures. Denitrifying bacterial isolates affiliated to Marinobacter spp. and Paracoccus spp. were isolated. Up regulation of the denitrification genes of strains GP59 and NL23 occurred in the biofilm cultures compared to the planktonic pure cultures. Denitrifying bacteria affiliated to the Stappia spp. were metabolically active in the biofilm cultures.<br><br>Conclusions: These results illustrate the dynamics of the microbial community in the denitrifying biofilm cultures in adapting to different environmental conditions. The NaCl concentration is an important factor affecting the microbial community in the biofilm cultures. Up regulation of the denitrification genes of M. nitratireducenticrescens strain GP59 and H. nitrativorans strain NL23 in the biofilm cultures suggests different mechanisms of regulation of the denitrification pathway in the biofilm. Other denitrifying heterotrophic bacteria are present in low proportions, suggesting that the biofilm has the potential to adapt to heterotrophic, non-methylotrophic environments.},
}
@article {pmid31421719,
year = {2019},
author = {Velmourougane, K and Prasanna, R and Supriya, P and Ramakrishnan, B and Thapa, S and Saxena, AK},
title = {Transcriptome profiling provides insights into regulatory factors involved in Trichoderma viride-Azotobacter chroococcum biofilm formation.},
journal = {Microbiological research},
volume = {227},
number = {},
pages = {126292},
doi = {10.1016/j.micres.2019.06.002},
pmid = {31421719},
issn = {1618-0623},
abstract = {Azotobacter chroococcum (Az) and Trichoderma viride (Tv) represent agriculturally important and beneficial plant growth promoting options which contribute towards nutrient management and biocontrol, respectively. When Az and Tv are co-cultured, they form a biofilm, which has proved promising as an inoculant in several crops; however, the basic aspects related to regulation of biofilm formation were not investigated. Therefore, whole transcriptome sequencing (Illumina NextSeq500) and gene expression analyses were undertaken, related to biofilm formation vis a vis Tv and Az growing individually. Significant changes in the transcriptome profiles of biofilm were recorded and validated through qPCR analyses. In-depth evaluation also identified several genes (phoA, phoB, glgP, alg8, sipW, purB, pssA, fadD) specifically involved in biofilm formation in Az, Tv and Tv-Az. Genes coding for RNA-dependent RNA polymerase, ABC transporters, translation elongation factor EF-1, molecular chaperones and double homeobox 4 were either up-regulated or down-regulated during biofilm formation. To our knowledge, this is the first report on the modulation of gene expression in an agriculturally beneficial association, as a biofilm. Our results provide insights into the regulatory factors involved during biofilm formation, which can help to improve the beneficial effects and develop more effective and promising plant- microbe associations.},
}
@article {pmid31421577,
year = {2019},
author = {Song, W and Qi, R and Zhao, L and Xue, N and Wang, L and Yang, Y},
title = {Bacterial community rather than metals shaping metal resistance genes in water, sediment and biofilm in lakes from arid northwestern China.},
journal = {Environmental pollution (Barking, Essex : 1987)},
volume = {254},
number = {Pt A},
pages = {113041},
doi = {10.1016/j.envpol.2019.113041},
pmid = {31421577},
issn = {1873-6424},
abstract = {Lakes in arid northwestern China are valuable freshwater resources that drive socioeconomic development. Environmental pollution can significantly influence the composition of microbial communities and the distribution of functional genes in lakes. This study investigated heavy metal pollution to identify possible correlations with metal resistance genes (MRGs) and bacterial community composition in water, sediment and biofilm samples from Bosten Lake and Ebi Lake in northwestern China. High levels of zinc were detected in all samples. However, the metals detected in the sediment samples of both lakes were determined to be at low risk levels according to an ecological index. The mercury resistance gene subtype merP had the greatest average abundance (4.61 × 10-3 copies per 16S rRNA) among all the samples, followed by merA and merC. The high abundance of merA in the pelagic zone rather than in benthic sediment suggests that the pelagic microbial community was important in mercury reduction. Proteobacteria were the main phylum found in the microbial communities in all samples. However, microbial communities in most of the water, sediment and biofilm samples had different compositions, indicating that the habitat niche plays an important role in shaping the bacterial communities in lakes. The microbial community, rather than the heavy metals, was the main driver of MRG distribution. The abundances of some bacterial genera involved in the decomposition of organic matter and the terrestrial nitrogen cycle were negatively correlated with heavy metals. This result suggests that metal pollution can adversely affect the biogeochemical processes that occur in lakes.},
}
@article {pmid31421576,
year = {2019},
author = {Lukwambe, B and Zhao, L and Nicholaus, R and Yang, W and Zhu, J and Zheng, Z},
title = {Bacterioplankton community in response to biological filters (clam, biofilm, and macrophytes) in an integrated aquaculture wastewater bioremediation system.},
journal = {Environmental pollution (Barking, Essex : 1987)},
volume = {254},
number = {Pt A},
pages = {113035},
doi = {10.1016/j.envpol.2019.113035},
pmid = {31421576},
issn = {1873-6424},
abstract = {Integrated systems with appropriate bio-filters can be used to treat aquaculture effluents. However, the information on bio-filters that alters the ecological functions of the bacterioplankton community (BC) in biodegradation of the aquaculture effluents remains controversial. In this study, we implemented a comprehensive restoration technology combined with bio-filters [biofilm, clam (Tegillarca granosa), and macrophytes (Spartina anglica)] to investigate their influence on the stability of the BC and nutrient removal. We found that the diversity of BC was linked with biogeochemical factors in processing and upcycling nitrogen-rich effluents into high-value biomass. The BC exhibited significant distinct patterns in the bio-filter areas. Potential biomarkers for constrained harmfully algae-bacteria (Nitriliruptoraceae, Bacillales, and Rhodobacteraceae) and nutrient removal were significantly higher in the bio-filters areas. The bio-filters significantly promoted the restoration effects of N and P balance by reducing 82.34% of total nitrogen (TN) and 81.64% of total phosphorus (TP) loads at the water interface. The main mechanisms for TN and TP removal and nutrient transformation were achieved by assimilation and absorption by the emergent macrophytes (Spartina anglica). The bio-filters significantly influenced the biodegradability and resolvability of particulate organic matter through ammonification, nitrification, and denitrification of microbes, which meliorated the nutrient removal. Beside bio-filter effects, the BC was significantly controlled by abiotic factors [nitrate (NO3--N), dissolved oxygen (DO), total nitrogen (TN), and water temperature (WT)], and biotic factors (chlorophyll ɑ and green algae). Our study revealed that the co-existence system with bio-filters may greatly improve our understanding on the ecological functions of the BC in aquaculture systems. Overall, combined bio-filters provide an opportunity for the development of efficient and optimized aquaculture wastewater treatment technology.},
}
@article {pmid31421403,
year = {2019},
author = {Martín, ML and Dassie, SA and Valenti, LE and Giacomelli, CE},
title = {A simple surface biofunctionalization strategy to inhibit the biofilm formation by Staphylococcus aureus on solid substrates.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {183},
number = {},
pages = {110432},
doi = {10.1016/j.colsurfb.2019.110432},
pmid = {31421403},
issn = {1873-4367},
abstract = {Staphylococcus aureus is an important opportunistic pathogen that causes a broad range of infections due to the bacteria capacity to form biofilms on medical devices. This work is aimed at inhibiting the biofilm formation by S. aureus on solid substrates using a simple surface biofunctionalization strategy. We previously found that surface biofunctionalization with structural perturbed albumin inhibited the initial stage of S. aureus adhesion. The current work extends this strategy with other plasma protein, fibrinogen, which in addition can be bond specifically to the cell wall-anchored proteins of S. aureus. The study of fibrinogen adsorption indicates that the fraction of surface-perturbed molecules is enlarged at long adsorption times and low protein concentration. In these conditions, a significant diminution of ca.60% of alive adhered bacteria were observed after 40 min and the biofilm formation was completely prevented. Thus, it seems that the inhibition of bacterial adhesion on substrates with surface-perturbed proteins represents a general trend even when specific interactions are present. On this basis, we developed a simple strategy to inhibit the formation of S. aureus biofilm, using thermally treated albumin or fibrinogen molecules prior to the substrate biofunctionalization. This strategy shows an excellent performance since the alive adhered bacteria diminishes ca. 90% at short incubation time, followed by the fully inhibition of biofilm formation. This novel and simple resource represents a change of the usual notion in avoiding post-surgery infections, mostly related to the use of medical devices.},
}
@article {pmid31420537,
year = {2019},
author = {Qin, Y and He, Y and She, Q and Larese-Casanova, P and Li, P and Chai, Y},
title = {Heterogeneity in respiratory electron transfer and adaptive iron utilization in a bacterial biofilm.},
journal = {Nature communications},
volume = {10},
number = {1},
pages = {3702},
doi = {10.1038/s41467-019-11681-0},
pmid = {31420537},
issn = {2041-1723},
support = {MCB1651732//National Science Foundation (NSF)/ ; },
abstract = {In Bacillus subtilis, robust biofilm formation requires large quantities of ferric iron. Here we show that this process requires preferential production of a siderophore precursor, 2,3-dihydroxybenzoate, instead of the siderophore bacillibactin. A large proportion of iron is associated extracellularly with the biofilm matrix. The biofilms are conductive, with extracellular iron potentially acting as electron acceptor. A relatively small proportion of ferric iron is internalized and boosts production of iron-containing enzymes involved in respiratory electron transfer and establishing strong membrane potential, which is key to biofilm matrix production. Our study highlights metabolic diversity and versatile energy generation strategies within B. subtilis biofilms.},
}
@article {pmid31420126,
year = {2019},
author = {Fulaz, S and Vitale, S and Quinn, L and Casey, E},
title = {Nanoparticle-Biofilm Interactions: The Role of the EPS Matrix.},
journal = {Trends in microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.tim.2019.07.004},
pmid = {31420126},
issn = {1878-4380},
abstract = {The negative consequences of biofilms are widely reported. A defining feature of biofilms is the extracellular matrix, a complex mixture of biomacromolecules, termed EPS, which contributes to reduced antimicrobial susceptibility. EPS targeting is a promising, but underexploited, approach to biofilm control allowing disruption of the matrix and thereby increasing the susceptibility to antimicrobials. Nanoparticles (NPs) can play a very important role as 'carriers' of EPS matrix disruptors, and several approaches have recently been proposed. In this review, we discuss the application of nanoparticles as antibiofilm technologies with a special emphasis on the role of the EPS matrix in the physicochemical regulation of the nanoparticle-biofilm interaction. We highlight the use of nanoparticles as a platform for a new generation of antibiofilm approaches.},
}
@article {pmid31419460,
year = {2019},
author = {Miryala, SK and Anbarasu, A and Ramaiah, S},
title = {Systems biology studies in Pseudomonas aeruginosa PA01 to understand their role in biofilm formation and multidrug efflux pumps.},
journal = {Microbial pathogenesis},
volume = {136},
number = {},
pages = {103668},
doi = {10.1016/j.micpath.2019.103668},
pmid = {31419460},
issn = {1096-1208},
abstract = {The antimicrobial resistance (AMR) exhibited against broad spectrum and new generation antibiotics used for Pseudomonas infections is a major threat and renders the treatment ineffective. In our present study, we have used a computational approach to understand various drug resistance mechanisms which contribute to Multi-Drug Resistance (MDR) in P. aeruginosa. The interaction network of 60 AMR genes along with the 337 functional interactions was analyzed. Functional enrichment analysis of AMR genes has shown that the genes in the network are mainly associated with efflux pump mechanisms, alginate biosynthesis, biofilm formation, and ampC beta-lactamase biosynthesis. Interestingly, the genes phoP, phoQ, and cat genes are observed to have roles in more than one drug-resistant mechanism. The genes phoP and phoQ apart from their role in two-component regulatory systems also play major roles in multidrug efflux pumps and alteration in drug target. The gene cat involves in alteration of drug target and enzymatic inactivation. The interaction network analysis has shown that the AMR genes oprJ, oprM, oprN, ampC, gyrA, mexA, oprD, mexB and nfxB have higher number of direct interactors and they are considered as the hub nodes in the network and these genes can be used as potential drug targets for developing new drugs. The results from our study will be helpful in better understanding of the antibiotic resistance mechanisms in P. aeruginosa. The gene targets reported, can be used for new drug discovery against Pseudomonas infections.},
}
@article {pmid31413280,
year = {2019},
author = {Inui, T and Palmer, RJ and Shah, N and Li, W and Cisar, JO and Wu, CD},
title = {Effect of mechanically stimulated saliva on initial human dental biofilm formation.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {11805},
doi = {10.1038/s41598-019-48211-3},
pmid = {31413280},
issn = {2045-2322},
support = {Intramural Research Program//U.S. Department of Health &amp; Human Services | NIH | National Institute of Dental and Craniofacial Research (NIDCR)/ ; NA//Mars Incorporated | Wm. Wrigley Jr. Company (Wrigley Company)/ ; },
abstract = {This study evaluated the impact of mechanically stimulated saliva on initial bacterial colonization. Interaction between oral bacteria and both unstimulated and stimulated saliva was examined in vitro by laying labeled bacteria over SDS-PAGE-separated salivary proteins. The effects of chewing on in vivo biofilm, microbial composition, and spatial arrangement were examined in two human volunteers using an intraoral stent containing retrievable enamel chips. In vitro experiments showed that bacterial binding to proteins from stimulated saliva was lower than that to proteins from unstimulated saliva. Lack of binding activity was noted with Streptococcus mutans and Lactobacillus casei. Human Oral Microbe Identification Microarray (HOMIM) analyses revealed a consistent chewing-related increase in the binding of Streptococcus anginosus and Streptococcus gordonii. Immunofluorescence microscopy demonstrated the presence of multi-species colonies and cells bearing different serotypes of the coaggregation-mediating streptococcal cell-surface receptor polysaccharides (RPS). Differences in bacterial colonization were noted between the two volunteers, while the type 4 RPS-reactive serotype was absent in one volunteer. Cells reacting with antibody against Rothia or Haemophilus were prominent in the early biofilm. While analysis of the data obtained demonstrated inter-individual variations in both in vitro and in vivo bacterial binding patterns, stimulating saliva with multiple orosensory stimuli may modulate oral bacterial colonization of tooth surfaces.},
}
@article {pmid31412645,
year = {2019},
author = {Magin, V and Garrec, N and Andrés, Y},
title = {Selection of Bacteriophages to Control In Vitro 24 h Old Biofilm of Pseudomonas Aeruginosa Isolated from Drinking and Thermal Water.},
journal = {Viruses},
volume = {11},
number = {8},
pages = {},
doi = {10.3390/v11080749},
pmid = {31412645},
issn = {1999-4915},
abstract = {Pseudomonas aeruginosa is an opportunistic pathogen that causes public healthcare issues. In moist environments, this Gram-negative bacterium persists through biofilm-associated contamination on surfaces. Bacteriophages are seen as a promising alternative strategy to chemical biocides. This study evaluates the potential of nine lytic bacteriophages as biocontrol treatments against nine environmental P. aerginosa isolates. The spot test method is preliminarily used to define the host range of each virus and to identify their minimum infectious titer, depending on the strain. Based on these results, newly isolated bacteriophages 14.1, LUZ7, and B1 are selected and assessed on a planktonic cell culture of the most susceptible isolates (strains MLM, D1, ST395E, and PAO1). All liquid infection assays are achieved in a mineral minimum medium that is much more representative of real moist environments than standard culture medium. Phages 14.1 and LUZ7 eliminate up to 90% of the PAO1 and D1 bacterial strains. Hence, their effectiveness is evaluated on the 24 h old biofilms of these strains, established on a stainless steel coupon that is characteristic of materials found in thermal and industrial environments. The results of quantitative PCR viability show a maximum reduction of 1.7 equivalent Log CFU/cm2 in the coupon between treated and untreated surfaces and shed light on the importance of considering the entire virus/host/environment system for optimizing the treatment.},
}
@article {pmid31411265,
year = {2019},
author = {Yu, MK and Kim, MA and Rosa, V and Hwang, YC and Del Fabbro, M and Sohn, WJ and Min, KS},
title = {Role of extracellular DNA in Enterococcus faecalis biofilm formation and its susceptibility to sodium hypochlorite.},
journal = {Journal of applied oral science : revista FOB},
volume = {27},
number = {},
pages = {e20180699},
doi = {10.1590/1678-7757-2018-0699},
pmid = {31411265},
issn = {1678-7765},
mesh = {Animals ; Biofilms/*drug effects/*growth &amp; development ; Cattle ; Colony Count, Microbial ; DNA, Bacterial/*pharmacology ; Dental Pulp Cavity/microbiology ; Deoxyribonucleases/*pharmacology ; Enterococcus faecalis/*drug effects/*growth &amp; development ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Polysaccharides, Bacterial/isolation &amp; purification ; Reproducibility of Results ; Sodium Hypochlorite/*pharmacology ; Time Factors ; },
abstract = {OBJECTIVE: This study investigated the role of extracellular deoxyribonucleic acid (eDNA) on Enterococcus faecalis (E. faecalis) biofilm and the susceptibility of E. faecalis to sodium hypochlorite (NaOCl).<br><br>METHODOLOGY: E. faecalis biofilm was formed in bovine tooth specimens and the biofilm was cultured with or without deoxyribonuclease (DNase), an inhibitor of eDNA. Then, the role of eDNA in E. faecalis growth and biofilm formation was investigated using colony forming unit (CFUs) counting, eDNA level assay, crystal violet staining, confocal laser scanning microscopy, and scanning electron microscopy. The susceptibility of E. faecalis biofilm to low (0.5%) or high (5%) NaOCl concentrations was also analyzed by CFU counting.<br><br>RESULTS: CFUs and biofilm formation decreased significantly with DNase treatment (p<0.05). The microstructure of DNase-treated biofilms exhibited less structured features when compared to the control. The volume of exopolysaccharides in the DNase-treated biofilm was significantly lower than that of control (p<0.05). Moreover, the CFUs, eDNA level, biofilm formation, and exopolysaccharides volume were lower when the biofilm was treated with DNase de novo when compared to when DNase was applied to matured biofilm (p<0.05). E. faecalis in the biofilm was more susceptible to NaOCl when it was cultured with DNase (p<0.05). Furthermore, 0.5% NaOCl combined with DNase treatment was as efficient as 5% NaOCl alone regarding susceptibility (p>0.05).<br><br>CONCLUSIONS: Inhibition of eDNA leads to decrease of E. faecalis biofilm formation and increase of susceptibility of E. faecalis to NaOCl even at low concentrations. Therefore, our results suggest that inhibition of eDNA would be beneficial in facilitating the efficacy of NaOCl and reducing its concentration.},
}
@article {pmid31410982,
year = {2019},
author = {Petrovich, ML and Ben Maamar, S and Hartmann, EM and Murphy, BT and Poretsky, RS and Wells, GF},
title = {Viral composition and context in metagenomes from biofilm and suspended growth municipal wastewater treatment plants.},
journal = {Microbial biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1751-7915.13464},
pmid = {31410982},
issn = {1751-7915},
support = {C-060//Chicago Biomedical Consortium/ ; //Northwestern University/ ; //Searle Funds at The Chicago Community Trust/ ; },
abstract = {Wastewater treatment plants (WWTPs) contain high density and diversity of viruses which can significantly impact microbial communities in aquatic systems. While previous studies have investigated viruses in WWTP samples that have been specifically concentrated for viruses and filtered to exclude bacteria, little is known about viral communities associated with bacterial communities throughout wastewater treatment systems. Additionally, differences in viral composition between attached and suspended growth wastewater treatment bioprocesses are not well characterized. Here, shotgun metagenomics was used to analyse wastewater and biomass from transects through two full-scale WWTPs for viral composition and associations with bacterial hosts. One WWTP used a suspended growth activated sludge bioreactor and the other used a biofilm reactor (trickling filter). Myoviridae, Podoviridae and Siphoviridae were the dominant viral families throughout both WWTPs, which are all from the order Caudovirales. Beta diversity analysis of viral sequences showed that samples clustered significantly both by plant and by specific sampling location. For each WWTP, the overall bacterial community structure was significantly different than community structure of bacterial taxa associated with viral sequences. These findings highlight viral community composition in transects through different WWTPs and provide context for dsDNA viral sequences in bacterial communities from these systems.},
}
@article {pmid31410606,
year = {2019},
author = {Wang, Z and Shi, LD and Lai, CY and Zhao, HP},
title = {Methane oxidation coupled to vanadate reduction in a membrane biofilm batch reactor under hypoxic condition.},
journal = {Biodegradation},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10532-019-09887-6},
pmid = {31410606},
issn = {1572-9729},
support = {LR17B070001//Natural Science Funds for Distinguished Young Scholar of Zhejiang Province/ ; 21577123//National Natural Science Foundation of China/ ; 51878596//National Natural Science Foundation of China/ ; 2018YFC1802203//National Key Technology R&amp;D Program/ ; },
abstract = {This study shows vanadate (V(V)) reduction in a methane (CH4) based membrane biofilm batch reactor when the concentration of dissolved oxygen (O2) was extremely low. V(IV) was the dominant products formed from V(V) bio-reduction, and majority of produced V(IV) transformed into precipitates with green color. Quantitative polymerase chain reaction and Illumina sequencing analysis showed that archaea methanosarcina were significantly enriched. Metagenomic predictive analysis further showed the enrichment of genes associated with reverse methanogenesis pathway, the key CH4-activating mechanism for anaerobic methane oxidation (AnMO), as well as the enrichment of genes related to acetate synthesis, in archaea. The enrichment of aerobic methanotrophs Methylococcus and Methylomonas implied their role in CH4 activation using trace level of O2, or their participation in V(V) reduction.},
}
@article {pmid31410037,
year = {2019},
author = {Bidossi, A and Bottagisio, M and De Grandi, R and Drago, L and De Vecchi, E},
title = {Chlorquinaldol, a topical agent for skin and wound infections: anti-biofilm activity and biofilm-related antimicrobial cross-resistance.},
journal = {Infection and drug resistance},
volume = {12},
number = {},
pages = {2177-2189},
doi = {10.2147/IDR.S211007},
pmid = {31410037},
issn = {1178-6973},
abstract = {Purpose: Persistence of skin and wound infections is nowadays accepted being linked to bacterial biofilms, which are highly recalcitrant to treatments and contribute to maintain a constant inflammation state and prevent a correct healing. Topical antimicrobials are the most common first-line self-medications; however, treatment failure is not uncommon and emerging resistance to antibiotics is alarming. Chlorquinaldol is an antimicrobial with a wide spectrum of activity and desirable characteristics for topical application. Aim of this study was to evaluate the efficacy of chlorquinaldol to prevent or eradicate S. aureus and P. aeruginosa biofilms, in comparison to classic topical antibiotics like gentamicin and fusidic acid.<br><br>Methods: Minimum inhibitory concentrations (MIC) were assessed for each strain and subinhibitory concentrations (½ and ¼ MIC) were used in the biofilm assay. Antimicrobial assays were performed during biofilm formation or were applied on mature biofilms and were evaluated by means of crystal violet assay and confocal laser scan microscopy.<br><br>Results: Chlorquinaldol and gentamicin were the most effective antimicrobials in both eradicating and preventing pathogens biofilm; however, resistance to methicillin and impermeability to carbapenems impaired chlorquinaldol effect. In addition, similarly to other hydroxyquinolines, aspecific metal chelation is here proposed as chlorquinaldol mode of action.<br><br>Conclusion: Relying on an acceptable antibiofilm and a wide spectrum of activity, an aspecific mode of action and consequent absence of resistance development, chlorquinaldol proved to be a good antimicrobial for topical use.},
}
@article {pmid31409687,
year = {2019},
author = {Jung, YC and Lee, MA and Lee, KH},
title = {Role of Flagellin-Homologous Proteins in Biofilm Formation by Pathogenic Vibrio Species.},
journal = {mBio},
volume = {10},
number = {4},
pages = {},
doi = {10.1128/mBio.01793-19},
pmid = {31409687},
issn = {2150-7511},
abstract = {The pathogenic bacterium Vibrio vulnificus exhibits the ability to form biofilm, for which initiation is dependent upon swimming motility by virtue of a polar flagellum. The filament of its flagellum is composed of multiple flagellin subunits, FlaA, -B, -C, and -D. In V. vulnificus genomes, however, open reading frames (ORFs) annotated by FlaE and -F are also present. Although neither FlaE nor FlaF is involved in filament formation and cellular motility, they are well expressed and secreted to the extracellular milieu through the secretion apparatus for flagellar assembly. In the extrapolymeric matrix of V. vulnificus biofilm, significant levels of FlaEF were detected. Mutants defective in both flaE and flaF formed significantly decreased biofilms compared to the wild-type biofilm. Thus, the potential role of FlaEF during the biofilm-forming process was investigated by exogenous addition of recombinant FlaEF (rFlaEF) to the biofilm assays. The added rFlaE and rFlaF were predominantly incorporated into the biofilm matrix formed by the wild type. However, biofilms formed by a mutant defective in exopolysaccharide (EPS) biosynthesis were not affected by added FlaEF. These results raised a possibility that FlaEF specifically interact with EPS within the biofilm matrix. In vitro pulldown assays using His-tagged rFlaEF or rFlaC revealed the specific binding of EPS to rFlaEF but not to rFlaC. Taken together, our results demonstrate that V. vulnificus FlaEF, flagellin-homologous proteins (FHPs), are crucial for biofilm formation by directly interacting with the essential determinant for biofilm maturation, EPS. Further analyses performed with other pathogenic Vibrio species demonstrated both the presence of FHPs and their important role in biofilm formation.IMPORTANCE Flagellar filaments of the pathogenic Vibrio species, including V. vulnificus, V. parahaemolyticus, and V. cholerae, are composed of multiple flagellin subunits. In their genomes, however, there are higher numbers of the ORFs encoding flagellin-like proteins than the numbers of flagellin subunits required for filament assembly. Since these flagellin-homologous proteins (FHPs) are well expressed and excreted to environments via a flagellin transport channel, their extracellular role in the pathogenic Vibrio has been enigmatic. Their biological significance, which is not related with flagellar functions, has been revealed to be in maturation of biofilm structures. Among various components of the extracellular polymeric matrix produced in the V. vulnificus biofilms, the exopolysaccharides (EPS) are dominant constituents and crucial in maturation of biofilms. The enhancing role of the V. vulnificus FHPs in biofilm formation requires the presence of EPS, as indicated by highly specific interactions among two FHPs and three EPS.},
}
@article {pmid31408199,
year = {2019},
author = {Ali, IAA and Cheung, BPK and Yau, JYY and Matinlinna, JP and Lévesque, CM and Belibasakis, GN and Neelakantan, P},
title = {The influence of substrate surface conditioning and biofilm age on the composition of Enterococcus faecalis biofilms.},
journal = {International endodontic journal},
volume = {},
number = {},
pages = {},
doi = {10.1111/iej.13202},
pmid = {31408199},
issn = {1365-2591},
support = {201702159011//University Research Committee, University of Hong Kong/ ; },
abstract = {AIM: To investigate the null hypothesis that neither the surface conditioning (collagen, serum, saliva) of hydroxyapatite (HA) discs, nor the biofilm age (3 days vs. 21 days) has a significant effect on the cellular and matrix composition of biofilms, using Enterococcus faecalis as the model organism.<br><br>METHODOLOGY: Sterile HA discs were conditioned with collagen, saliva or serum, and inoculated with E. faecalis to form 3-day and 21-day-old biofilms. Unconditioned discs served as controls. The biofilms were analysed using culture-dependent and independent (confocal microscopy and biochemical analysis) methods, to determine the colony-forming units and the biofilm matrix composition (polysaccharides and proteins), respectively. Statistical analyses were performed using appropriate parametric and nonparametric tests (P = 0.05).<br><br>RESULTS: Collagen conditioning significantly increased the number of CFUs in the 21-day biofilms, compared to the 3-day biofilms (P < 0.05). Although the biochemical analysis revealed that surface conditioning had no significant effect on the total carbohydrate content in the 21-day biofilms, confocal microscopic analysis revealed that collagen and saliva conditioning selectively increased the polysaccharide content of 21-day biofilms, compared to the 3-day biofilms (P < 0.05).<br><br>CONCLUSIONS: The results of this study raise an important methodological concern that the substrate conditioning substances and biofilm age differentially influence the cellular and extracellular matrix components of E. faecalis biofilms.},
}
@article {pmid31407877,
year = {2019},
author = {Nie, L and Li, Y and Chen, S and Li, K and Huang, Y and Zhu, Y and Sun, Z and Zhang, J and He, Y and Cui, M and Wei, S and Qiu, F and Zhong, C and Liu, W},
title = {Biofilm Nanofiber-Coated Separators for Dendrite-Free Lithium Metal Anode and Ultrahigh-Rate Lithium Batteries.},
journal = {ACS applied materials &amp; interfaces},
volume = {11},
number = {35},
pages = {32373-32380},
doi = {10.1021/acsami.9b08656},
pmid = {31407877},
issn = {1944-8252},
abstract = {Rechargeable batteries that combine high energy density with high power density are highly demanded. However, the wide utilization of lithium metal anode is limited by the uncontrollable dendrite growth, and the conventional lithium-ion batteries (LIBs) commonly suffer from low rate capability. Here, we for the first time develop a biofilm-coated separator for high-energy and high-power batteries. It reveals that the coating of Escherichia coli protein nanofibers can improve electrolyte wettability and lithium transference number and enhance adhesion between separators and electrodes. Thus, lithium dendrite growth is impeded because of the uniform distribution of the Li-ion flux. The modified separator also enables the stable cycling of high-voltage Li|Li1.2Mn0.6Ni0.2O2 (LNMO) cells at an extremely high rate of 20 C, delivering a high specific capacity of 83.1 mA h g-1, which exceeds the conventional counterpart. In addition, the modified separator in the Li4Ti5O12|LNMO full cell also exhibits a larger capacity of 68.2 mA h g-1 at 10 C than the uncoated separator of 37.4 mA h g-1. Such remarkable performances of the modified separators arise from the conformal, adhesive, and endurable coating of biofilm nanofibers. Our work opens up a new opportunity for protein-based biomaterials in practical application of high-energy and high-power batteries.},
}
@article {pmid31407437,
year = {2019},
author = {Daubert, DM and Weinstein, BF},
title = {Biofilm as a risk factor in implant treatment.},
journal = {Periodontology 2000},
volume = {81},
number = {1},
pages = {29-40},
doi = {10.1111/prd.12280},
pmid = {31407437},
issn = {1600-0757},
abstract = {This article summarizes the microbiological findings at dental implants, drawing distinctions between the peri-implant microbiome and the periodontal microbiome, and summarizes what is known regarding biofilm as a risk factor for specific stages of implant treatment. Targeted microbial analysis is reviewed as well as the latest results from open-ended sequencing of the peri-implant flora. At this time there remains a lack of consensus for a specific microbial profile that is associated with peri-implantitis, suggesting that there may be other factors which influence the microbiome such as titanium surface dissolution. Therapeutic interventions to address the biofilm are presented at the preoperative, perioperative, and postoperative stages. Evidence supports that perioperative chlorhexidine reduces biofilm-related implant complications and failure. Regular maintenance for dental implants is also shown to reduce peri-implant mucositis and implant failure. Maintenance procedures should aim to disrupt the biofilm without damaging the titanium dioxide surface layer in an effort to prevent further oxidation. Evidence supports the use of glycine powder air polishing as a valuable adjunct to conventional therapies for use at implant maintenance visits. For the treatment of peri-implantitis, nonsurgical therapy has not been shown to be effective, and while surgical intervention is not always predictable, it has been shown to be superior to nonsurgical treatment for decontamination of the implant surface that is not covered by bone.},
}
@article {pmid31406097,
year = {2019},
author = {Saad, A and Nikaido, T and Abdou, A and Matin, K and Burrow, MF and Tagami, J},
title = {Inhibitory effect of zinc-containing desensitizer on bacterial biofilm formation and root dentin demineralization.},
journal = {Dental materials journal},
volume = {},
number = {},
pages = {},
doi = {10.4012/dmj.2018-352},
pmid = {31406097},
issn = {1881-1361},
abstract = {This study compared the effect of a novel zinc containing, Caredyne Shield (CS), and a fluoroaluminocalciumsilicate-based, Nanoseal (NS) desensitizers on dentin tubule occlusion, inhibition of Streptococcus mutans (S. mutans) biofilm growth, and resistance to bacterial demineralization. Desensitizers were applied to simulated hypersensitive bovine dentin, with distilled water used as a control. S. mutans biofilms were grown on the surface of each specimen in an oral biofilm simulator. CS showed the least bacterial count and water insoluble glucan amount followed by NS. Transverse micro radiography revealed that both CS and NS showed significant reduction in mineral loss and lesion depth of the associated lesion. Scanning electron micrographs showed that the two desensitizers formed obvious depositions on the dentin surfaces, occlusion of tubules and mineral tag formation.},
}
@article {pmid31405860,
year = {2019},
author = {Willems, HME and Stultz, JS and Coltrane, ME and Fortwendel, JP and Peters, BM},
title = {Disparate Candida albicans biofilm formation in clinical lipid emulsions due to capric acid mediated inhibition.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.01394-19},
pmid = {31405860},
issn = {1098-6596},
abstract = {Receipt of parenteral nutrition (PN) remains an independent risk factor for developing catheter-related blood stream infections (CR-BSI) caused by fungi, including the polymorphic fungus Candida albicans that is notoriously adept at forming drug-resistant biofilm structures. Among a variety of macronutrients, PN solutions contain lipid emulsions to supply daily essential fats and are often delivered via central venous catheters (CVC). Therefore, using an in vitro biofilm model system, we sought to determine whether various clinical lipid emulsions differentially impacted biofilm growth in C. albicans We observed that lipid emulsions Intralipid® and Omegaven® both stimulated C. albicans biofilm formation during growth in minimal medium or a macronutrient PN solution. Conversely, Smoflipid® inhibited C. albicans biofilm formation by approximately 50%. Follow up studies revealed that while Smoflipid did not impair C. albicans growth, it did significantly inhibit hypha formation and hyphal elongation. Moreover, growth inhibition could be recapitulated in Intralipid® when supplemented with capric acid-a fatty acid present in Smoflipid® but absent in Intralipid®. Capric acid was also found to dose-dependently inhibit C. albicans biofilm formation in PN solutions. This is the first study to directly compare different clinical lipid emulsions for their capacity to affect C. albicans biofilm growth. Results derived from this study necessitate further research regarding different lipid emulsions and rates of fungal-associated CR-BSIs.},
}
@article {pmid31405233,
year = {2019},
author = {Kwiecińska-Piróg, J and Skowron, K and Bogiel, T and Białucha, A and Przekwas, J and Gospodarek-Komkowska, E},
title = {Vitamin C in the Presence of Sub-Inhibitory Concentration of Aminoglycosides and Fluoroquinolones Alters Proteus mirabilis Biofilm Inhibitory Rate.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {8},
number = {3},
pages = {},
doi = {10.3390/antibiotics8030116},
pmid = {31405233},
issn = {2079-6382},
abstract = {Vitamin C has antimicrobial activity and is often used as an oral supplement accompanying antibiotic treatment in urinary tract infections (UTI). Proteus mirabilis is the third common species responsible for UTIs that are mostly treated with fluoroquinolones or aminoglycosides. Treatment of the UTI caused by P. mirabilis is problematic due to the ability to form biofilm on the urinary catheters. The aim of the study was to evaluate the influence of ascorbic acid in combination with antibiotics on P. mirabilis abilities to form biofilm. The susceptibility of P. mirabilis reference strain ATCC® 29906™ and four clinical strains isolated from the urine samples of patients with urinary catheter were evaluated according to EUCAST recommendations. The influence of ascorbic acid (0.4 mg × mL-1) in combination with antibiotics on biofilm formation was evaluated spectrophotometrically. Aminoglycosides at sub-inhibitory concentrations more successfully limited biofilm formation by P. mirabilis strains without ascorbic acid addition. Inhibition rate differences at the lowest concentrations of gentamicin and amikacin were statistically significant (p ≤ 0.05). Ascorbic acid addition to the culture medium limited the inhibitory effect of fluoroquinolones, facilitating biofilm formation by P. mirabilis strains. The addition of ascorbic acid during aminoglycosides therapy may disturb treatment of urinary tract infections related to the presence of P. mirabilis biofilm.},
}
@article {pmid31405172,
year = {2019},
author = {Guzzon, A and Di Pippo, F and Congestri, R},
title = {Wastewater Biofilm Photosynthesis in Photobioreactors.},
journal = {Microorganisms},
volume = {7},
number = {8},
pages = {},
doi = {10.3390/microorganisms7080252},
pmid = {31405172},
issn = {2076-2607},
support = {QLK3-CT2002-01938//EC/ ; },
abstract = {Photosynthetic performance of algal-bacterial biofilms from an Italian wastewater treatment plant was studied in a flow-lane photobioreactor at different irradiances, temperatures, and flow regime to evaluate the effects of these environmental parameters on biofilms' functioning, in view of application of these communities in wastewater biological treatment. Pulse amplitude modulated fluorescence was used to estimate the effective quantum yield of PSII (ΔF/Fm') of the light-acclimated biofilms and to perform rapid light curves (RLCs) for the determination of the photosynthetic parameters (rel.ETRmax, α, Ik). Chl a, ash free dry weight (AFDW), and dry weight (DW) were measured to assess phototrophic and whole biofilm biomass development over time. From the analysis of photosynthetic parameter variation with light intensity, temperature and flow rate, it was possible to identify the set of experimental values favoring biofilm photosynthetic activity. Biomass increased over time, especially at the highest irradiances, where substrata were fastly colonized and mature biofilms developed at all temperatures and flow conditions tested.},
}
@article {pmid31404843,
year = {2019},
author = {Kłodzińska, SN and Wan, F and Jumaa, H and Sternberg, C and Rades, T and Nielsen, HM},
title = {Utilizing nanoparticles for improving anti-biofilm effects of azithromycin: A head-to-head comparison of modified hyaluronic acid nanogels and coated poly (lactic-co-glycolic acid) nanoparticles.},
journal = {Journal of colloid and interface science},
volume = {555},
number = {},
pages = {595-606},
doi = {10.1016/j.jcis.2019.08.006},
pmid = {31404843},
issn = {1095-7103},
abstract = {HYPOTHESIS: The widespread resistance of bacteria to traditional antibiotic treatments has expedited the search for novel therapies against these pathogens. The hypothesis of this work is that two distinctively different polymeric delivery systems, specifically D-α-tocopherol polyethylene glycol 1000 succinate (TPGS)-poly(lactic-co-glycolic acid) (PLGA) nanoparticles and octenyl succinic anhydride-modified low molecular weight hyaluronic acid (OSA-HA) nanogels may be used to substantially improve the properties of azithromycin, allowing its use for effective treatment of Pseudomonas aeruginosa biofilm infections.<br><br>EXPERIMENTS: Azithromycin was encapsulated in both delivery systems and the physicochemical properties of the loaded delivery systems, including size, surface charge and drug loading were evaluated. Additionally, particle interaction with a mucin layer, penetration into a bacterial biofilm, prevention of biofilm formation and eradication of pre-formed biofilms, the influence on production of virulence factors and bacterial motility as well as cytotoxicity towards hepatocytes and lung epithelial cells were compared head-to-head.<br><br>FINDINGS: The TPGS-PLGA nanoparticles noticeably improved the antimicrobial activity and the biofilm prevention activity of azithromycin whereas the OSA-HA nanogels showed reduced mucin interactions together with improved reduction of pre-formed biofilms and maintained the low eukaryotic cell cytotoxicity of azithromycin.},
}
@article {pmid31404739,
year = {2019},
author = {Sun, G and Wan, J and Sun, Y and Li, H and Chang, C and Wang, Y},
title = {Enhanced removal of nitrate and refractory organic pollutants from bio-treated coking wastewater using corncobs as carbon sources and biofilm carriers.},
journal = {Chemosphere},
volume = {237},
number = {},
pages = {124520},
doi = {10.1016/j.chemosphere.2019.124520},
pmid = {31404739},
issn = {1879-1298},
abstract = {The quality of the bio-treated coking wastewater (BTCW) is difficult to meet increasingly stringent coking wastewater discharge standards and future wastewater recycling needs. In this study, the pre-treatment process of BTCW was installed including the two up-flow fixed-bed bioreactors (UFBRs) which were separately filled with alkali-pretreated or no alkali-pretreated corncobs used as solid carbon sources as well as biofilm carriers. Results showed that this pre-treatment process could significantly improve the biodegradability of BTCW and increase the C/N ratio. Thus, over 90% of residual nitrate in BTCW were removed stably. Furthermore, GC-MS analysis confirmed that the typical refractory organic matters decreased significantly after UFBRs pre-treatment. High-throughput sequencing analysis using 16S rRNA demonstrated that dominant denitrifiers, fermentative bacteria and refractory-organic-pollutants-degrading bacteria co-existed inside the UFBRs system. Compared with no alkali-pretreated corncobs, alkali-pretreated corncobs provided more porous structure and much stable release of carbon to guarantee the growth and the quantity of the functional bacteria such as denitrifiers. This study indicated that the UFBRs filled with alkali-pretreated corncobs could be utilized as an effective alternative for the enhanced treatment of the BTCW.},
}
@article {pmid31404326,
year = {2019},
author = {Wang, S and Wang, Y and Wang, Y and Duan, Z and Ling, Z and Wu, W and Tong, S and Wang, H and Deng, S},
title = {Theaflavin-3,3'-Digallate Suppresses Biofilm Formation, Acid Production, and Acid Tolerance in Streptococcus mutans by Targeting Virulence Factors.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1705},
doi = {10.3389/fmicb.2019.01705},
pmid = {31404326},
issn = {1664-302X},
abstract = {As one of the most important cariogenic pathogens, Streptococcus mutans has strong abilities to form biofilms, produce acid and tolerate acid. In present study, we found that theaflavin-3,3'-digallate (TF3) had an inhibitory effect on S. mutans UA159 in vitro. Visualized by field emission-scanning electron microscopy, the suppressed formation of S. mutans biofilms grown with TF3 at sub-inhibitory concentrations could be attributed to the reduced biofilm matrix, which was proven to contain glucans and extracellular DNA (eDNA). Glucan-reduced effect of TF3 was achieved by down-regulating expression levels of gtfB, gtfC, and gtfD encoding glucosyltransferases. Besides, TF3 reduced eDNA formation of S. mutans by negatively regulating lrgA, lrgB, and srtA, which govern cell autolysis and membrane vesicle components. Furthermore, TF3 also played vital roles in antagonizing preformed biofilms of S. mutans. Bactericidal effects of TF3 became significant when its concentrations increased more than twofold of minimum inhibitory concentration (MIC). Moreover, the capacities of S. mutans biofilms to produce acid and tolerate acid were significantly weakened by TF3 at MIC. Based on real-time PCR (RT-PCR) analysis, the mechanistic effects of TF3 were speculated to comprise the inhibition of enolase, lactate dehydrogenase, F-type ATPase and the agmatine deiminase system. Moreover, TF3 has been found to downregulate LytST, VicRK, and ComDE two component systems in S. mutans, which play critical roles in the regulatory network of virulence factors. Our present study found that TF3 could suppress the formation and cariogenic capacities of S. mutans biofilms, which will provide new strategies for anti-caries in the future.},
}
@article {pmid31403663,
year = {2019},
author = {Shafeeq, S and Pannanusorn, S and Elsharabasy, Y and Ramírez-Zavala, B and Morschhäuser, J and Römling, U},
title = {Impact of manganese on biofilm formation and cell morphology of Candida parapsilosis clinical isolates with different biofilm forming abilities.},
journal = {FEMS yeast research},
volume = {},
number = {},
pages = {},
doi = {10.1093/femsyr/foz057},
pmid = {31403663},
issn = {1567-1364},
abstract = {The commensal species Candida parapsilosis is an emerging human pathogen that has the ability to form biofilms. In this study, we explored the impact of the divalent cations cobalt (Co2+), copper (Cu2+), iron (Fe3+), manganese (Mn2+), nickel (Ni2+) and zinc (Zn2+) on biofilm formation of clinical isolates of C. parapsilosis with no, low and high biofilm-forming abilities at 30 and 37°C. All strains beside one isolate showed a concentration dependent enhancement of biofilm formation at 30°C in the presence of Mn2+ with a maximum at 2 mM. The biofilm forming ability of no- and low-biofilm forming isolates was more than two-fold enhanced in the presence of 2 mM Mn2+, while the effect in high biofilm forming isolate was significantly less pronounced. Of note, cells in the biofilms of no- and low-biofilm forming strains differentiated into yeast and pseudohyphal cells similar in morphology to high biofilm formers. The biofilm transcriptional activator BCR1 has a dual developmental role in the absence and presence of 2 mM Mn2+ as it promoted biofilm formation of no biofilm forming strains, and, surprisingly, suppressed cells of no biofilm forming strains to develop into pseudohyphae and/or hyphae. Thus, environmental conditions can significantly affect the amount of biofilm formation and cell morphology of C. parapsilosis with Mn2+ to overcome developmental blocks to trigger biofilm formation and to partially relieve BCR1 suppressed cell differentiation.},
}
@article {pmid31402901,
year = {2019},
author = {van Vugt, TAG and Arts, JJ and Geurts, JAP},
title = {Antibiotic-Loaded Polymethylmethacrylate Beads and Spacers in Treatment of Orthopedic Infections and the Role of Biofilm Formation.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1626},
doi = {10.3389/fmicb.2019.01626},
pmid = {31402901},
issn = {1664-302X},
abstract = {Polymethylmethacrylate (PMMA) also referred as (acrylic) bone cement is a non-degradable biomaterial that has been used in clinical orthopedic practice for several decades. PMMA can be used in a plain formulation, but is often used in an antibiotic-loaded formulation in (primary and revision) arthroplasty and in treatment of orthopedic infections as prosthetic joint infections (PJI) and chronic osteomyelitis. In treatment of PJIs antibiotic-loaded PMMA is often used as a carrier material for local antibiotic delivery in addition to treatment with systemic antibiotics. In this case, the antibiotic-loaded PMMA is often used as a spacer or as a bead chain. Since the introduction of PMMA as an antibiotic carrier there is a tremendous amount of scientific and clinical papers published, which studied numerous different aspects of antibiotic-loaded PMMA. This paper will review the research regarding basic principles of antibiotic-loaded PMMA as mechanism of action, antibiotic-release capacities, choice of antibiotics and influences on mechanical properties of PMMA. Subsequently, concerns regarding the application of antibiotic-loaded PMMA, biofilm formation, antibiotic resistance and local or systemic toxicity will be discussed. In addition to these subjects, the role of antibiotic loaded PMMA in clinical treatment of PJIs and chronic osteomyelitis is discussed in the final part of this paper.},
}
@article {pmid31402749,
year = {2019},
author = {Krantz, GP and Lucas, K and Wunderlich, EL and Hoang, LT and Avci, R and Siuzdak, G and Fields, MW},
title = {Bulk phase resource ratio alters carbon steel corrosion rates and endogenously produced extracellular electron transfer mediators in a sulfate-reducing biofilm.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-15},
doi = {10.1080/08927014.2019.1646731},
pmid = {31402749},
issn = {1029-2454},
abstract = {Desulfovibrio alaskensis G20 biofilms were cultivated on 316 steel, 1018 steel, or borosilicate glass under steady-state conditions in electron-acceptor limiting (EAL) and electron-donor limiting (EDL) conditions with lactate and sulfate in a defined medium. Increased corrosion was observed on 1018 steel under EDL conditions compared to 316 steel, and biofilms on 1018 carbon steel under the EDL condition had at least twofold higher corrosion rates compared to the EAL condition. Protecting the 1018 metal coupon from biofilm colonization significantly reduced corrosion, suggesting that the corrosion mechanism was enhanced through attachment between the material and the biofilm. Metabolomic mass spectrometry analyses demonstrated an increase in a flavin-like molecule under the 1018 EDL condition and sulfonates under the 1018 EAL condition. These data indicate the importance of S-cycling under the EAL condition, and that the EDL is associated with increased biocorrosion via indirect extracellular electron transfer mediated by endogenously produced flavin-like molecules.},
}
@article {pmid31402466,
year = {2019},
author = {Balasundararajan, V and Dananjeyan, B},
title = {Occurrence of diversified N-acyl homoserine lactone mediated biofilm-forming bacteria in rice rhizoplane.},
journal = {Journal of basic microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1002/jobm.201900202},
pmid = {31402466},
issn = {1521-4028},
support = {5-5/2014 - TS VII//Ministry of Human Resource Development, New Delhi, India/ ; },
abstract = {Quorum sensing (QS)-mediated biofilm-forming rhizobacteria are indispensable due to their competitiveness in the crop rhizosphere. In the present work, we have reported on the occurrence of diversified bacterial species capable of producing N-acyl homoserine lactone (AHL) as the QS signal in the roots of a rice plant grown under field conditions. The AHL-producing bacteria were directly isolated from the rice root by the biosensor reporter (Chromobacterium violaceum CV026) overlay method and characterized for biofilm production by the microtiter plate method. A total of 48 QS-positive bacterial isolates were purified from different aged (7, 20, 24, 26, and 36 days) rice seedlings. The in vitro biofilm production and genetic diversity as revealed by BOX-PCR fingerprinting showed high variability among the isolates. Most of the best biofilm-forming isolates produced a N-butyryl dl-homoserine lactone (a C4-AHL type) signal in the medium. The 16S ribosomal RNA (rRNA) gene sequence of these putative elite isolates identified that they were close to Aeromonas hydrophila (QS7-4; QS36-2), A. enteropelongenes (QS20-8), A. veronii (QS36-3), Enterobacter sp. (QS20-11), Klebsiella pneumoniae (QS24-6), Kosakonia cowanii (QS24-21), Providentia rettigeri (QS24-2), Sphingomonas aquatilis (QS24-17), and Pseudomonas sihuiensis (QS24-20). These strains profusely colonized the rice root upon inoculation and formed biofilms on the surface of the root under gnotobiotic conditions. Developing inoculants from these strains would ensure competitive colonization on the rhizoplane of the crop through their biofilm and thereby improve plant growth and health.},
}
@article {pmid31401655,
year = {2019},
author = {Bajoul Kakahi, F and Ly, S and Tarayre, C and Deschaume, O and Bartic, C and Wagner, P and Compère, P and Derdelinckx, G and Blecker, C and Delvigne, F},
title = {Modulation of fungal biofilm physiology and secondary product formation based on physico-chemical surface properties.},
journal = {Bioprocess and biosystems engineering},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00449-019-02187-6},
pmid = {31401655},
issn = {1615-7605},
abstract = {Relative to the amount of knowledge concerning bacterial biofilms, little is known about the impact of physico-chemical properties of support material on fungal biofilm adhesion and physiology. In the field of industrial fermentation, large-scale production of low-cost fungal secondary product is a challenging area of research. In the present work, the effect of physico-chemical surface properties of five different materials (Teflon, glass, Viton™ rubber, silicon rubber, and stainless steel) on the production of class II hydrophobins (HFBI and HFBII) from Trichoderma reesei (HFB2a-2) and Trichoderma harzianum) was evaluated. Two culture systems (shake flask and drip flow reactor (DFR)) were used in this study to promote biomass growth and the production of hydrophobins. Furthermore, the effect of physico-chemical surface properties (hydrophobicity, surface energy) and surface texture (roughness) of support material on the initial colonization and attachment of the fungal biofilm was evaluated. Maximum biofilm productivity was obtained using Viton™ rubber for T. reesei and Viton™ rubber and stainless steel as support materials for T. harzianum. Scanning electron microscope (SEM) revealed that fungal biofilm adhesion was higher on the rough hydrophobic Viton rubber surface as compared to the smooth hydrophobic Teflon surface. Initial colonization initiated because of surface irregularities and holes in the material as hyphal filaments. Moreover, compared to traditional submerged fermentation, a significant increase in biofilm productivity for both strains (T. reesei, T. harzianum) in all five materials was obtained.},
}
@article {pmid31401462,
year = {2019},
author = {Czuban, M and Wulsten, D and Wang, L and Di Luca, M and Trampuz, A},
title = {Release of different amphotericin B formulations from PMMA bone cements and their activity against Candida biofilm.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {183},
number = {},
pages = {110406},
doi = {10.1016/j.colsurfb.2019.110406},
pmid = {31401462},
issn = {1873-4367},
abstract = {Amphotericin B is used for local delivery from polymethylmethacrylate to treat fungal prosthetic joint infections. The optimal amphotericin B formulation and the influence of different poragens in the bone cements are unknown. To investigate the necessary amount of amphotericin B in the bone cement to prevent Candida biofilm several amphotericin B formulations were studied: non-liposomal and liposomal with or without poragen gentamicin. For the non-liposomal formulation, standard bile salt, the sodium deoxycholate, was used and additionally N-methyl-D-glucamine/palmitate was applied. The activity of the released amphotericin B was tested against C. albicans, C. glabrata, C. parapsilosis and C. krusei biofilms with application of the isothermal calorimeter and standard microbiological methods. Compressive strength was measured before and after antifungal elution from the cements. There is less aggregated N-methyl-D-glucamine/palmitate amphotericin B released but its antifungal activity is equivalent with the deoxycholate amphotericin B. The minimum quantity of antifungal preventing the Candida biofilm formation is 12.5 mg in gram of polymer powder for both non-liposomal formulations. The addition of gentamicin reduced the release of sodium deoxycholate amphotericin B. Gentamicin can be added to N-methyl-D-glucamine/palmitate amphotericin B in order to boost the antifungal release. When using liposomal amphotericin B more drug is released. All amphotericin B formulations were active against Candida biofilms. Although compressive strength slightly decreased, the obtained values were above the level of strength recommended for the implant fixation. The finding of this work might be beneficial for the treatment of the prosthetic joint infections caused by Candida spp.},
}
@article {pmid31400984,
year = {2019},
author = {Ionescu, A and Brambilla, E and Hahnel, S},
title = {Does recharging dental restorative materials with fluoride influence biofilm formation?.},
journal = {Dental materials : official publication of the Academy of Dental Materials},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.dental.2019.07.019},
pmid = {31400984},
issn = {1879-0097},
abstract = {OBJECTIVES: To investigate the influence of recharging dental restorative materials with fluoride on biofilm formation.<br><br>METHODS: Specimens produced from a high-viscosity glass ionomer cement (HVGIC), a resin-modified glass ionomer cement (RMGIC), and a resin-based composite (RBC) were randomly allotted to incubation in artificial saliva either for one week (AS-1), for five weeks (AS-5), for five weeks including twice/day brushing with 1450ppm NaF toothpaste (AS-5-brush), or one-time exposition to 5000ppm NaF after five weeks of incubation (AS-5-exp). Human enamel was used as reference. Surface roughness and the release of fluoride from the specimens was determined; biofilm formation was simulated using mono- or multispecies microbiological models and analysed employing an MTT-based approach and confocal laser-scanning microscopy.<br><br>RESULTS: Monospecies biofilm formation was significantly reduced on HVGIC in comparison to RMGIC and RBC. It was also reduced on HVGIC and enamel after treatment with fluoride in groups AS-5-brush and AS-5-exp in comparison to AS-5. These effects were particularly pronounced after 24h, and less pronounced after 48h of biofilm formation. In the multispecies microbiological model, similar observations were identified for HVGIC, while for enamel a significant reduction in biofilm formation was observed in groups AS-5-brush and AS-5-exp. No significant effect of fluoride treatments was identified for RMGIC and RBC, regardless of the microbiological model applied.<br><br>SIGNIFICANCE: These data indicate that biofilm formation on the surfaces of a glass ionomer cement and enamel can be relevantly influenced by treatment with fluoride. Enamel may serve as a fluoride reservoir which requires regular recharge.},
}
@article {pmid31400892,
year = {2019},
author = {Vasileiou, NGC and Chatzopoulos, DC and Cripps, PJ and Ioannidi, KS and Gougoulis, DA and Chouzouris, TM and Lianou, DT and Gonzalez-Valerio, TC and Vallverdu, RG and Argyros, S and Cesio, M and Font, I and Mavrogianni, VS and Petinaki, E and Fthenakis, GC},
title = {Evaluation of efficacy of a biofilm-embedded bacteria-based vaccine against staphylococcal mastitis in sheep-A randomized, placebo-controlled field study.},
journal = {Journal of dairy science},
volume = {},
number = {},
pages = {},
doi = {10.3168/jds.2019-16287},
pmid = {31400892},
issn = {1525-3198},
abstract = {Our objective was to evaluate the efficacy of a vaccine against staphylococcal mastitis in 5 dairy sheep farms, with 316 ewes in the vaccinated (V) group and 307 in the control (C) group studied throughout a lactation period. Two administrations of the vaccine were performed during the last stage of gestation of ewes. Starting 15 d after lambing and at monthly intervals thereafter, up to 9 milk samplings were performed for bacteriological and cytological examinations. Staphylococcal isolates recovered were examined for biofilm formation. Blood samples were collected for measurement of IgG poly-N-acetylglucosamine-specific antibodies. The most frequently isolated bacteria were staphylococci: 56.4 and 76.1%, respectively, of total isolates recovered from ewes of group V and C, respectively; staphylococci as causal agents of mastitis were isolated less frequently from V (5.3%) than in ewes in C (10.3%). Among mastitis-associated staphylococcal isolates recovered from V ewes, a smaller proportion was biofilm-forming than among ones from C: 53.2% versus 74.9% of isolates; biofilm-forming staphylococci as causal agents of mastitis were isolated less frequently from ewes in group V (2.3%) than in ewes in group C (6.0%). Anti-poly-N-acetylglucosamine-specific antibody values increased in V ewes and were higher than in C; a greater proportion of ewes with low antibody titers developed staphylococcal mastitis (41.4%) than of V ewes with high antibody titers (17.0%). Incidence risk of mastitis, staphylococcal mastitis, and biofilm-associated staphylococcal mastitis was smaller in V than in C: 36.7, 17.1, and 8.0% versus 44.3, 30.9, and 18.9%, respectively. The first case of staphylococcal mastitis occurred later in V than in C: 3rd versus 2nd sampling point. Overall, efficacy of the vaccine was 44.6% for staphylococcal mastitis, 57.7% for biofilm-associated staphylococcal mastitis, 33.1% for staphylococcal intramammary infection, and 51.5% for biofilm-associated staphylococcal intramammary infection. Nevertheless, vaccination should not be the only means for controlling mastitis; other udder health management measures should be included therein to improve control of the infection.},
}
@article {pmid31400863,
year = {2019},
author = {Hans, S and Fatima, Z and Hameed, S},
title = {Retrograde signaling disruption influences ABC superfamily transporter, ergosterol and chitin levels along with biofilm formation in Candida albicans.},
journal = {Journal de mycologie medicale},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.mycmed.2019.07.003},
pmid = {31400863},
issn = {1773-0449},
abstract = {OBJECTIVE: The rise in fungal infections is alarming due to emergence of multidrug drug resistance (MDR). Hence elucidating novel drug targets to circumvent the problem of MDR warrants immediate attention. This study analyzes the effect of retrograde (RTG) signaling disruption on major MDR mechanisms and virulence of the human pathogenic fungal species Candida albicans.<br><br>MATERIAL AND METHODS: Drug transporter activity was measured by rhodamine 6G (R6G) efflux. Membrane damage was studied by propidium iodide intake and ergosterol level determination. Cell wall effect was estimated by quantifying chitin levels and cell sedimentation rate. Biofilm formation was visualized by calcoflour white and crystal violet staining and measured by dry mass and MTT assay. Cell adherence to buccal epithelial cell was determined by trypan blue staining and MTT assay. Virulence was studied using nematode model Caenorhabditis elegans.<br><br>RESULT: We demonstrated that mutant of transcription factor CaRTG3 leads to impaired efflux activity of ATP Binding Cassette (ABC) superfamily multidrug transporters. We further uncover that rtg3 mutant exhibited a disrupted membrane, decreased ergosterol levels and increased chitin content. Furthermore, RTG signaling disruption leads to inhibited biofilm formation and cell adherence to buccal epithelial cells. Lastly, rtg3 mutant displayed a reduced infectivity in C. elegans illustrating its vulnerability as antifungal target. Interestingly, all the abrogated phenotypes could be rescued in the revertant strain of rtg3 mutant.<br><br>CONCLUSION: Present study establishes a link between RTG signaling, drug efflux and biofilm formation and validates CaRTG3 as antifungal target. Intricate studies are needed to further understand and exploit this therapeutic opportunity.},
}
@article {pmid31400688,
year = {2019},
author = {Li, H and Zhou, L and Lin, H and Zhang, W and Xia, S},
title = {Nitrate effects on perchlorate reduction in a H2/CO2-based biofilm.},
journal = {The Science of the total environment},
volume = {694},
number = {},
pages = {133564},
doi = {10.1016/j.scitotenv.2019.07.370},
pmid = {31400688},
issn = {1879-1026},
abstract = {The H2/CO2-based membrane biofilm reactor (H2/CO2-MBfR) that effectively combines microporous diffusions of H2 and CO2 is efficient in removing perchlorate (ClO4-). Nitrate (NO3-) is a common oxidized contaminant frequently coexists with ClO4- in water, with the NO3- concentration in most ClO4--contaminated waters being several orders of magnitude higher than ClO4-. Determining the effect of NO3- on ClO4- reduction is a critical issue in practice. The ClO4- reduction performance, biofilm microbial community and influencing mechanism were investigated under a series of feed NO3- loadings in this work. ClO4- reduction was slightly promoted when NO3--N levels were <10 mg/L and inhibited at higher NO3--N levels. Denitrification competed more strongly for H2 than ClO4- reduction, regardless of H2 availability. A higher NO3--N loading was a strong driving force to change the biofilm microbial community. Betaproteobacteria were the dominant bacteria at all stages, and the biofilm reactor was enriched in Methyloversatilis and Zoogloea (31.9-56.5% and 10.6-25.8%, respectively). Changes in the relative amounts of Methyloversatilis and Zoogloea coincided with changes in the ClO4- fluxes and removal efficiencies and the relative abundances of nitrogen cycle functional genes. These results suggest that Methyloversatilis and Zoogloea likely follow independent reduction mechanisms for ClO4- removal.},
}
@article {pmid31398534,
year = {2019},
author = {Dieser, SA and Fessia, AS and Zanotti, AR and Raspanti, CG and Odierno, LM},
title = {Fibronectin and laminin induce biofilm formation by Streptococcus uberis and decrease its penicillin susceptibility.},
journal = {Microbial pathogenesis},
volume = {136},
number = {},
pages = {103652},
doi = {10.1016/j.micpath.2019.103652},
pmid = {31398534},
issn = {1096-1208},
abstract = {The aim of this study was to determine the effect of fibronectin and laminin on the in vitro biofilm formation by Streptococcus uberis and the susceptibility to penicillin under planktonic and biofilm growth conditions. We observed that a high percentage (76.5%) of the S. uberis isolates was weak biofilm producers in Todd Hewitt Broth (THB). A high percentage of moderate (38.2%) or strong (53%) biofilm producers was observed in THB supplemented with laminin or fibronectin, respectively. All S. uberis isolates growing as planktonic cells were sensitive to penicillin. Minimum biofilm inhibitory concentrations (MBICs) were ranging between 0.25 and 2 μg/ml, whereas minimum biofilm eradication concentrations (MBECs) ranging from 8 to 256 μg/ml. These results show that biofilm-growing S. uberis cells required higher concentrations of the antibiotic than those needed to inhibit planktonic cells. Similar MBICs of penicillin were obtained when S. uberis cells growing in THB supplemented or not with laminin or fibronectin, whereas the MBECs markedly increased when one of two proteins were added to culture medium compared with the medium without proteins. To the best of our knowledge, this is the first report of decreased susceptibility to penicillin likely related to a higher production of biofilms stimulated by laminin or fibronectin. Therapeutic failures of penicillin to treat S. uberis infections may be due to biofilm formation.},
}
@article {pmid31398514,
year = {2019},
author = {Shin, NR and Yi, YJ and Choi, JS},
title = {Hand motor functions on the presence of red fluorescent dental biofilm in older community-dwelling Koreans.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2019.08.010},
pmid = {31398514},
issn = {1873-1597},
abstract = {BACKGROUND: The Quantitative Light-induced Fluorescence-Digital (QLF-D) system visualizes old and mature dental biofilm as red fluorescence. Risk factors for poor oral hygiene have been identified, however, few studies have evaluated the relationship between mature dental biofilm and hand motor functions. This study aimed to investigate the effects of two important manual motor functions for object manipulation -handgrip strength and manual dexterity- on the presence of red fluorescent dental biofilm in older community-dwelling Koreans using QLF-D, an optical device that reveals dental biofilm.<br><br>METHODS: This cross-sectional study included 70 Korean participants aged ≥65 years, all of whom completed questionnaires and were tested for handgrip strength and manual dexterity. In total, 840 dental surfaces were photographed using QLF-D, and ΔR20 values, which reflect mature dental biofilm accumulation, were calculated. The t-test was performed to analyze the differences in the △R20 values according to sociodemographic characteristics, health-related characteristics and hand motor functions, while multiple linear regression analysis was used to investigate the effects of hand motor functions on the △R20 values.<br><br>RESULTS: Multivariate regression analysis revealed that handgrip strength (β = -0.294) was the factor most strongly affecting mature dental biofilm accumulation (ΔR20), followed by tooth-brushing time (β = -0.262) and manual dexterity (β = -0.241).<br><br>CONCLUSIONS: Reductions in handgrip strength and manual dexterity were independent risk factors for pathogenic dental biofilm accumulation. The results of this investigation suggest that programs designed to prevent the decline, as well as improve, handgrip strength and manual dexterity might improve the oral hygiene of older adults.},
}
@article {pmid31398473,
year = {2019},
author = {Arenas-Vivo, A and Amariei, G and Aguado, S and Rosal, R and Horcajada, P},
title = {An Ag-loaded photoactive nano-metal organic framework as a promising biofilm treatment.},
journal = {Acta biomaterialia},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.actbio.2019.08.011},
pmid = {31398473},
issn = {1878-7568},
abstract = {Surface biofilm inhibition is still currently a considerable challenge. Among other organisms, Staphylococcus aureus is notable for its ability to form a strong biofilm with proved resistance to chemotherapy. Contamination of high-touch surfaces with S. aureus biofilm not only promotes disease spread but also generates tremendous health-associated costs. Therefore, development of new bactericidal and antiadhesive surface coatings is a priority. Considering that metal-organic frameworks (MOFs) have recently emerged as promising antibacterial agents, we originally report here the synthesis of a multi-active silver-containing nanoscaled MOF composite as a potential surface coating against S. aureus biofilm owing to a triple effect: intrinsic bactericide activity of the MOF, biocidal character of silver nanoparticles (AgNPs), and photoactivity after UVA irradiation. AgNPs were successfully entrapped within the benchmarked nanoscaled porous photoactive titanium(IV) aminoterephthalate MIL-125(Ti)NH2 using a simple and efficient impregnation-reduction method. After complete characterization of the composite thin film, its antibacterial and anti-adherent properties were fully evaluated. After UVA irradiation, the composite coating exhibited relevant bacterial inhibition and detachment, improved ligand-to-cluster charge transfer, and steady controlled delivery of Ag+. These promising results establish the potential of this composite as an active coating for biofilm treatment on high-touch surfaces (e.g., surgical devices, door knobs, and rail bars). STATEMENT OF SIGNIFICANCE: Surface contamination due to bacterial biofilm formation is still a demanding issue, as it causes severe disease spread. One possible solution is the development of antifouling and antibacterial surface coatings. In this work, we originally propose the use of photoactive metal-organic frameworks (MOFs) for biofilm treatment. The novelty of this work relies on the following: i) the treatment of strongly contaminated surfaces, as previous studies with MOFs have exclusively addressed biofilm prevention; ii) this pioneering work reports both antiadherent effect, which removes the biofilm, and bacterial inhibition; iii) our original successful strategy has never been proposed thus far, involving the multi-active combination of 1) intrinsic antibacterial effect of a photoactive titanium-based nanoMOF, 2) immobilization of biocide silver nanoparticles, and 3) improved anti-bioadherent effect upon irradiation of the composite coating.},
}
@article {pmid31398188,
year = {2019},
author = {Rai, LS and Singha, R and Sanchez, H and Chakraborty, T and Chand, B and Bachellier-Bassi, S and Chowdhury, S and d'Enfert, C and Andes, DR and Sanyal, K},
title = {The Candida albicans biofilm gene circuit modulated at the chromatin level by a recent molecular histone innovation.},
journal = {PLoS biology},
volume = {17},
number = {8},
pages = {e3000422},
doi = {10.1371/journal.pbio.3000422},
pmid = {31398188},
issn = {1545-7885},
abstract = {Histone H3 and its variants regulate gene expression but the latter are absent in most ascomycetous fungi. Here, we report the identification of a variant histone H3, which we have designated H3VCTG because of its exclusive presence in the CTG clade of ascomycetes, including Candida albicans, a human pathogen. C. albicans grows both as single yeast cells and hyphal filaments in the planktonic mode of growth. It also forms a three-dimensional biofilm structure in the host as well as on human catheter materials under suitable conditions. H3VCTG null (hht1/hht1) cells of C. albicans are viable but produce more robust biofilms than wild-type cells in both in vitro and in vivo conditions. Indeed, a comparative transcriptome analysis of planktonic and biofilm cells reveals that the biofilm circuitry is significantly altered in H3VCTG null cells. H3VCTG binds more efficiently to the promoters of many biofilm-related genes in the planktonic cells than during biofilm growth, whereas the binding of the core canonical histone H3 on the corresponding promoters largely remains unchanged. Furthermore, biofilm defects associated with master regulators, namely, biofilm and cell wall regulator 1 (Bcr1), transposon enhancement control 1 (Tec1), and non-dityrosine 80 (Ndt80), are significantly rescued in cells lacking H3VCTG. The occupancy of the transcription factor Bcr1 at its cognate promoter binding sites was found to be enhanced in the absence of H3VCTG in the planktonic form of growth resulting in enhanced transcription of biofilm-specific genes. Further, we demonstrate that co-occurrence of valine and serine at the 31st and 32nd positions in H3VCTG, respectively, is essential for its function. Taken together, we show that even in a unicellular organism, differential gene expression patterns are modulated by the relative occupancy of the specific histone H3 type at the chromatin level.},
}
@article {pmid31397415,
year = {2019},
author = {Sampaio, GG and Leódido, G and Gonçalves, LM and Benini Paschoal, MA},
title = {In vitro antimicrobial potential of infant mouthwashes against streptococcus mutans biofilm: A preliminary study.},
journal = {Indian journal of dental research : official publication of Indian Society for Dental Research},
volume = {30},
number = {3},
pages = {399-402},
doi = {10.4103/ijdr.IJDR_500_17},
pmid = {31397415},
issn = {1998-3603},
abstract = {Background: Children and teenagers accumulate dental plaque easily due to immature motor coordination present at this specific age. Thus, chemical solutions such as mouthwashes are used for biofilm control. The widespread use of mouthwash could potentially change the oral environment though there is no evidence of its effects on the biofilm.<br><br>Aim: The present study aimed to investigate the in vitro antimicrobial potential of infant mouthwashes on mature Streptococcus mutans biofilm.<br><br>Methods: The susceptibility of S. mutans biofilm UA 159 (ATCC700610) to infant mouthwashes was tested with childrens mouthwashes containing the following active agents: G1-cetylpyridinium chloride, G2-xylitol and triclosan and G3-Malva sylvestris and xylitol. Phosphage-buffered saline (PBS) was used at the negative control (G4). In this study, cariogenic biofilm was exposed once a day for one minute to the mouthwashes over a period of five days. Following this, an aliquot of each mouthwash used was seeded in brain heart infusion (BHI) agar and then incubated at 37°C, 5% CO2 for 48 h. The results were expressed as colony-forming units (CFU) and converted into log10. The results were submitted to ANOVA and Tukey's test at 5%.<br><br>Results: It was observed 7.75, 7.66, and 7.49 CFUlog10 values to G1, G2, and G3, respectively, with 9.53 CFUlog10 value to G4. Accordingly, all studied mouthwashes showed no significant statistical difference between them but with statistically significant bacterial reduction in comparison to control group.<br><br>Conclusion: Infant mouthwashes presented a highly significant antimicrobial effect on cariogenic biofilm in an in vitro model, which raises concern when used by a young population.},
}
@article {pmid31397177,
year = {2019},
author = {Acquaviva, R and D'Angeli, F and Malfa, GA and Ronsisvalle, S and Garozzo, A and Stivala, A and Ragusa, S and Nicolosi, D and Salmeri, M and Genovese, C},
title = {Antibacterial and anti-biofilm activities of walnut pellicle extract (Juglans regia L.) against coagulase-negative staphylococci.},
journal = {Natural product research},
volume = {},
number = {},
pages = {1-6},
doi = {10.1080/14786419.2019.1650352},
pmid = {31397177},
issn = {1478-6427},
abstract = {Juglans regia L. (common walnut) is a deciduous tree belonging to Juglandaceae family. Since ancient time, walnut was widely used in traditional medicine for its antioxidant, antidiabetic, antimicrobial, anti-inflammatory, anti-atherogenic and liver-protective effects. In this work, the antibacterial and anti-biofilm activities of walnuts pellicle extract against coagulase-negative staphylococci were evaluated. Qualitative chemical analysis was performed by the thin layer chromatography. UPLC-Ms/Ms was used to identify the chemical composition of J. regia extract. The total flavonoid and phenolic contents were determined by the Aluminium chloride and Folin-Ciocalteu methods, respectively. The extract showed antibacterial activity with MIC ranging from 3.60 to 461.75 µg/ml and MBC ranging from 461.75 to >461.75 µg/ml. Furthermore, it significantly reduced biofilm biomass and cell viability in a dose-dependent manner. Biological activities of J. regia extract may be due to its high flavonoid and phenolic contents. The obtained results are promising and they deserve further scientific investigations.},
}
@article {pmid31396394,
year = {2019},
author = {Cameron, LC and Bonis, B and Phan, CQ and Kent, LA and Lee, AK and Hunter, RC},
title = {A putative enoyl-CoA hydratase contributes to biofilm formation and the antibiotic tolerance of Achromobacter xylosoxidans.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {20},
doi = {10.1038/s41522-019-0093-6},
pmid = {31396394},
issn = {2055-5008},
abstract = {Achromobacter xylosoxidans has attracted increasing attention as an emerging pathogen in patients with cystic fibrosis. Intrinsic resistance to several classes of antimicrobials and the ability to form robust biofilms in vivo contribute to the clinical manifestations of persistent A. xylosoxidans infection. Still, much of A. xylosoxidans biofilm formation remains uncharacterized due to the scarcity of existing genetic tools. Here we demonstrate a promising genetic system for use in A. xylosoxidans; generating a transposon mutant library which was then used to identify genes involved in biofilm development in vitro. We further described the effects of one of the genes found in the mutagenesis screen, encoding a putative enoyl-CoA hydratase, on biofilm structure and tolerance to antimicrobials. Through additional analysis, we find that a fatty acid signaling compound is essential to A. xylosoxidans biofilm ultrastructure and maintenance. This work describes methods for the genetic manipulation of A. xylosoxidans and demonstrated their use to improve our understanding of A. xylosoxidans pathophysiology.},
}
@article {pmid31396193,
year = {2019},
author = {Woodburn, KW and Jaynes, JM and Clemens, LE},
title = {Evaluation of the Antimicrobial Peptide, RP557, for the Broad-Spectrum Treatment of Wound Pathogens and Biofilm.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1688},
doi = {10.3389/fmicb.2019.01688},
pmid = {31396193},
issn = {1664-302X},
abstract = {The relentless growth of multidrug resistance and generation of recalcitrant biofilm are major obstacles in treating wounds, particularly in austere military environments where broad-spectrum pathogen coverage is needed. Designed antimicrobial peptides (dAMPs) are constructed analogs of naturally occurring AMPs that provide the first line of defense in many organisms. RP557 is a dAMP resulting from iterative rational chemical structural analoging with endogenous AMPs, human cathelicidin LL-37 and Tachyplesin 1 and the synthetic D2A21 used as structural benchmarks. RP557 possesses broad spectrum activity against Gram-positive and Gram-negative bacteria and fungi, including recalcitrant biofilm with substantial selective killing over bacterial cells compared to mammalian cells. RP557 did not induce resistance following chronic passages of Pseudomonas aeruginosa and Staphylococcus aureus at subinhibitory concentrations, whereas concurrently run conventional antibiotics, gentamycin, and clindamycin, did. Furthermore, RP557 was able to subsequently eliminate the generated gentamycin resistant P. aeruginosa and clindamycin resistant S. aureus strains without requiring an increase in minimum inhibitory concentration (MIC) concentrations. RP557 was evaluated further in a MRSA murine wound abrasion infection model with a topical application of 0.2% RP557, completely eliminating infection. If these preclinical results are translated into the clinical setting, RP557 may become crucial for the empirical broad-spectrum treatment of wound pathogens, so that infections can be reduced to a preventable complication of combat-related injuries.},
}
@article {pmid31396166,
year = {2019},
author = {Yan, S and Wu, G},
title = {Can Biofilm Be Reversed Through Quorum Sensing in Pseudomonas aeruginosa?.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1582},
doi = {10.3389/fmicb.2019.01582},
pmid = {31396166},
issn = {1664-302X},
abstract = {Pseudomonas aeruginosa is a Gram-negative bacterium causing diseases in plants, animals, and humans, and its drug resistance is a major concern in medical care. Biofilms play an important role in P. aeruginosa drug resistance. Three factors are most important to induce biofilm: quorum sensing (QS), bis-(3'-5')-cyclic diguanosine monophosphate (c-di-GMP), and small RNAs (sRNAs). P. aeruginosa has its own specific QS system (PQS) besides two common QS systems, LasI-LasR and RhlI-RhlR, in bacteria. PQS is interesting not only because there is a negative regulation from RhlR to pqsR but also because the null mutation in PQS leads to a reduced biofilm formation. Furthermore, P. aeruginosa dispersed cells have physiological features that are distinct between the planktonic cells and biofilm cells. In response to a low concentration of c-di-GMP, P. aeruginosa cells can disperse from the biofilms to become planktonic cells. These raise an interesting hypothesis of whether biofilm can be reversed through the QS mechanism in P. aeruginosa. Although a single factor is certainly not sufficient to prevent the biofilm formation, it necessarily explores such possibility. In this hypothesis, the literature is analyzed to determine the negative regulation pathways, and then the transcriptomic data are analyzed to determine whether this hypothesis is workable or not. Unexpectedly, the transcriptomic data reveal a negative regulation between lasI and psqR. Also, the individual cases from transcriptomic data demonstrate the negative regulations of PQS with laslI, laslR, rhlI, and rhlR under different experiments. Based on our analyses, possible strategies to reverse biofilm formation are proposed and their clinic implications are addressed.},
}
@article {pmid31394187,
year = {2019},
author = {Barrios-Gumiel, A and Sanchez-Nieves, J and Pérez-Serrano, J and Gómez, R and de la Mata, FJ},
title = {PEGylated AgNP covered with cationic carbosilane dendrons to enhance antibacterial and inhibition of biofilm properties.},
journal = {International journal of pharmaceutics},
volume = {569},
number = {},
pages = {118591},
doi = {10.1016/j.ijpharm.2019.118591},
pmid = {31394187},
issn = {1873-3476},
abstract = {This work focuses on preparation of silver nanoparticles (AgNP) covered with cationic carbosilane dendrons and poly(ethylene glycol) (PEG). It is well known that AgNP and cationic carbosilane dendritic systems present antibacterial properties. On the other hand, PEG ligand provides antifouling properties and improved biocompatibility. Hence, combination of both ligands, carbosilane dendrons and PEG, on the AgNP surface can be a way to improve antibacterial capacity of AgNP. The new family of heterofunctionalized AgNP has been directly synthesized using silver precursor and cationic carbosilane dendrons and PEG ligands containing a thiol moiety. AgNP were characterized by TEM, TGA, UV, 1H NMR, DLS, Z potential, XRD. The antibacterial capacity of these systems was evaluated against E. coli and S. aureus. The results confirmed the influence of both silver core and cationic carbosilane dendrons on the activity of these systems. The behaviour obtained for PEGylated systems were slightly lower than for non-PEGylated AgNP. However, hemolysis assays demonstrated that this decrease was compensated for by the greater biocompatibility. To more completely characterize the improvements of PEGylation on dendronized AgNP, one non-PEGylated and one PEGylated AgNP were tested for resistance in a planktonic state. Both AgNPs barely affected the minimum inhibitory concentration (MIC) whereas reference antibiotics generated significant resistance. In addition, relevant improvement in biofilm inhibition was achieved by dendronized AgNP after PEGylation.},
}
@article {pmid31393795,
year = {2019},
author = {Fronzo, C},
title = {An early, biofilm-focused wound management approach.},
journal = {Journal of wound care},
volume = {28},
number = {8},
pages = {524-526},
doi = {10.12968/jowc.2019.28.8.524},
pmid = {31393795},
issn = {0969-0700},
abstract = {Wound care experts at the 2019 EWMA conference described the need to adopt biofilm-based wound care, the case for silver dressings, the importance of early intervention and the benefits of effective antibiofilm technologies. Camila Fronzo, JWC chief sub editor, summarises the main points.},
}
@article {pmid31392229,
year = {2019},
author = {Abbaszadeh, A and Tehmasebi-Foolad, A and Rajabzadeh, A and Beigi-Brojeni, N and Zarei, L},
title = {Effects of Chitosan/Nano Selenium Biofilm on Infected Wound Healing in Rats; An Experimental Study.},
journal = {Bulletin of emergency and trauma},
volume = {7},
number = {3},
pages = {284-291},
doi = {10.29252/beat-0703012},
pmid = {31392229},
issn = {2322-2522},
abstract = {Objective: The present study was aimed at assessment of effect of application of Chitosan/Nano Selenium biofilm on infected wound healing in rats.<br><br>Methods: Sixty-eight male Wistar rats were randomized into four groups of 17 animals each. In group I (Normal) the wounds were created with no infection. In group II (MRSA), the wounds were infected with methicillin resistant Staphylococcus aureus(MRSA). In group III (MRSA/CHIT), animals with infected wounds were dressed with chitosan biofilm only. In group IV (MRSA/CHIT/NS), animals with infected wounds were dressed with Chitosan/Nano Selenium biofilm.<br><br>Results: There were significant differences in comparisons of group IV and other groups, particularly in terms of cellular infiltration and neovascularization. During the study period, scores for neovascularization was significantly higher in group IV rats than other groups (P<0.05). Polymorphonuclear (PMN) and mononuclear (MNC) cell count and fibroblast cell proliferation in group IV were significantly higher than those of other experimental groups (P<0.05).<br><br>Conclusion: Chitosan/Nano Selenium biofilm resulted in significant improvement in histopathological indices in full thickness infected wound healing.},
}
@article {pmid31391891,
year = {2019},
author = {Cox, KE and Melander, C},
title = {Anti-biofilm activity of quinazoline derivatives against Mycobacterium smegmatis.},
journal = {MedChemComm},
volume = {10},
number = {7},
pages = {1177-1179},
doi = {10.1039/c9md00156e},
pmid = {31391891},
issn = {2040-2511},
abstract = {Bacteria employ a number of mechanisms to resist the effects of antibiotics, including the formation of biofilms. We explored the anti-biofilm capabilities of a library of compounds based upon a 2-aminoquinazoline (2-AQ) scaffold against Mycobacterium smegmatis. This study resulted in the identification of 2-AQ derivatives with biofilm inhibition activity against M. smegmatis.},
}
@article {pmid31390848,
year = {2019},
author = {Pennone, V and Sanz-Gaitero, M and O'Connor, P and Coffey, A and Jordan, K and van Raaij, MJ and McAuliffe, O},
title = {Inhibition of L. monocytogenes Biofilm Formation by the Amidase Domain of the Phage vB_LmoS_293 Endolysin.},
journal = {Viruses},
volume = {11},
number = {8},
pages = {},
doi = {10.3390/v11080722},
pmid = {31390848},
issn = {1999-4915},
support = {14/F/881//Food Institutional Research Measure/ ; },
abstract = {Listeria monocytogenes is a ubiquitous Gram-positive bacterium that is a major concern for food business operators because of its pathogenicity and ability to form biofilms in food production environments. Bacteriophages (phages) have been evaluated as biocontrol agents for L. monocytogenes in a number of studies and, indeed, certain phages have been approved for use as anti-listerial agents in food processing environments (ListShield and PhageGuard Listex). Endolysins are proteins produced by phages in the host cell. They cleave the peptidoglycan cell wall, thus allowing release of progeny phage into the environment. In this study, the amidase domain of the phage vB_LmoS_293 endolysin (293-amidase) was cloned and expressed in Escherichia. coli(E. coli). Muralytic activity at different concentrations, pH and temperature values, lytic spectrum and activity against biofilms was determined for the purified 293-amidase protein. The results showed activity on autoclaved cells at three different temperatures (20 °C, 37 °C and 50 °C), with a wider specificity (L. monocytogenes 473 and 3099, a serotype 4b and serogroup 1/2b-3b-7, respectively) compared to the phage itself, which targets only L. monocytogenes serotypes 4b and 4e. The protein also inhibits biofilm formation on abiotic surfaces. These results show the potential of using recombinant antimicrobial proteins against pathogens in the food production environment.},
}
@article {pmid31389671,
year = {2019},
author = {Martínez-García, S and Ortega-Peña, S and De Haro-Cruz, MJ and Aguilera-Arreola, MG and Alcántar-Curiel, MD and Betanzos-Cabrera, G and Jan-Roblero, J and Pérez-Tapia, SM and Rodríguez-Martínez, S and Cancino-Diaz, ME and Cancino-Diaz, JC},
title = {Non-biofilm-forming commensal Staphylococcus epidermidis isolates produce biofilm in the presence of trypsin.},
journal = {MicrobiologyOpen},
volume = {},
number = {},
pages = {e906},
doi = {10.1002/mbo3.906},
pmid = {31389671},
issn = {2045-8827},
support = {269242//Consejo Nacional de Ciencia y Tecnología (CONACyT)/ ; 20181167//SIP-Instituto Politécnico Nacional Mexico/ ; //Instituto Politécnico Nacional fellowships/ ; //Sistema Nacional de Investigadores, CONACyT/ ; //CONACyT/ ; 247489//PDCPN/ ; IN220613//Program UNAM-DGAPA-PAPIIT/ ; },
abstract = {Epidemiological studies comparing clinical and commensal Staphylococcus epidermidis isolates suggest that biofilm formation is a discriminant biomarker. A study showed that four non-biofilm-forming clinical S. epidermidis isolates could form an induced biofilm by trypsin treatment, suggesting that S. epidermidis can form biofilms in a protease-independent way and in a trypsin-induced way. In this study, the trypsin capacity to induce biofilm formation was evaluated in non-biofilm-forming S. epidermidis isolates (n = 133) in order to support this mechanism and to establish the importance of total biofilms (meaning the sum of protease-independent biofilm and trypsin-induced biofilm). Staphylococcus epidermidis isolates from ocular infections (OI; n = 24), prosthetic joint infections (PJI; n = 64), and healthy skin (HS-1; n = 100) were screened for protease-independent biofilm formation according to Christensen's method. The result was that there are significant differences (p < .0001) between clinical (43.2%) and commensal (17%) protease-independent biofilm producers. Meanwhile, non-biofilm-forming isolates were treated with trypsin, and biofilm formation was evaluated by the same method. The number of commensal trypsin-induced biofilm producers significantly increased from 17% to 79%. In contrast, clinical isolates increased from 43.2% to 72.7%. The comparison between clinical and commensal total biofilm yielded no significant differences (p = .392). A similar result was found when different isolation sources were compared (OI vs. HS-1 and PJI vs. HS-1). The genotype icaA- /aap+ was associated with the trypsin-induced biofilm phenotype; however, no correlation was observed between aap mRNA expression and the level of trypsin-induced biofilm phenotype. Studying another group of commensal S. epidermidis non-biofilm-forming isolates (HS-2; n = 139) from different body sites, it was found that 70 isolates (60.3%) formed trypsin-induced biofilms. In conclusion, trypsin is capable of inducing biofilm production in non-biofilm-forming commensal S. epidermidis isolates with the icaA- /aap+ genotype, and there is no significant difference in total biofilms when comparing clinical and commensal isolates, suggesting that total biofilms are not a discriminant biomarker.},
}
@article {pmid31388951,
year = {2019},
author = {Bó, LG and Almeida, RM and Cardoso, CMM and Zavarize, DG and Brum, SS and Mendonça, ARV},
title = {Acetylsalicylic acid biosorption onto fungal-bacterial biofilm supported on activated carbons: an investigation via batch and fixed-bed experiments.},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11356-019-06075-0},
pmid = {31388951},
issn = {1614-7499},
abstract = {This study reports on acetylsalicylic acid (ASA) biosorption onto fungal-bacterial biofilm supported on two types of activated carbons (one commercial type made of coconut fibers, CAC, and one other manufactured from fruit rinds of Hymenaea stigonocarpa Mart., HYAC, which after biofilm inoculation, they were named CAC-b and HYAC-b), via batch and fixed-bed experiments. These materials were characterized by BET Specific Surface Area and Scanning Electronic Microscopy (SEM). Biosorption onto HYAC-b was 57.2% higher than HYAC. Despite presenting the highest biosorption capacity over time (qt = 85.4 ± 0.82 mg g-1), CAC-b had a lower increase in efficiency (32.4%) compared to CAC. Kinetic data from the biosorption experiments responded well to the pseudo-first-order model thus suggests the predominance of physisorption, while without biofilm presence, there was a better agreement with the pseudo-second-order model, suggesting chemisorption. The possible interaction mechanism of ASA to biofilm was attributed to ionic forces between the drug in anionic form and eventual presence of cationic by-products of the biologically active surface metabolism. Biosorption equilibrium data responded better to the Sips model and CAC-b presented the highest biosorption capacity (qe = 292.4 ± 2.01 mg g-1). A combination of faster volumetric flow rates, higher inlet concentrations and shorter beds accelerated the breakthrough time of ASA biosorption in the fixed-bed experiments. These operational conditions affected C/Co ratio in the following magnitude order: volumetric flow rate < inlet concentration < bed height. Breakthrough data responded better to the modified dose-response model compared to Thomas and Yoon-Nelson models.},
}
@article {pmid31385644,
year = {2019},
author = {Quan, K and Zhang, Z and Chen, H and Ren, X and Ren, Y and Peterson, BW and van der Mei, HC and Busscher, HJ},
title = {Artificial Channels in an Infectious Biofilm Created by Magnetic Nanoparticles Enhanced Bacterial Killing by Antibiotics.},
journal = {Small (Weinheim an der Bergstrasse, Germany)},
volume = {},
number = {},
pages = {e1902313},
doi = {10.1002/smll.201902313},
pmid = {31385644},
issn = {1613-6829},
support = {2016YFC1100402//National Key Research and Development Program of China/ ; 21334004//National Natural Science Foundation of China/ ; 11574222//National Natural Science Foundation of China/ ; 21522404//National Natural Science Foundation of China/ ; //UMCG/ ; },
abstract = {The poor penetrability of many biofilms contributes to the recalcitrance of infectious biofilms to antimicrobial treatment. Here, a new application for the use of magnetic nanoparticles in nanomedicine to create artificial channels in infectious biofilms to enhance antimicrobial penetration and bacterial killing is proposed. Staphylococcus aureus biofilms are exposed to magnetic-iron-oxide nanoparticles (MIONPs), while magnetically forcing MIONP movement through the biofilm. Confocal laser scanning microscopy demonstrates artificial channel digging perpendicular to the substratum surface. Artificial channel digging significantly (4-6-fold) enhances biofilm penetration and bacterial killing efficacy by gentamicin in two S. aureus strains with and without the ability to produce extracellular polymeric substances. Herewith, this work provides a simple, new, and easy way to enhance the eradication of infectious biofilms using MIONPs combined with clinically applied antibiotic therapies.},
}
@article {pmid31384892,
year = {2019},
author = {He, ZY and Zhou, W and Huang, ZW and Liang, JP and Jiang, W},
title = {[The effect of Streptococcus mutans luxS gene on mixed-species biofilm communities].},
journal = {Shanghai kou qiang yi xue = Shanghai journal of stomatology},
volume = {28},
number = {2},
pages = {113-117},
pmid = {31384892},
issn = {1006-7248},
abstract = {PURPOSE: To evaluate the effect of S.mutans luxS gene on mixed-species biofilms communities.<br><br>METHODS: Biofilms were formed by S. mutans (wild type strain, its luxS overexpression strain and luxS knockout strain) and Lactobacillus acidophilus (ATCC4356) with a ratio of 1:1 at 37℃ for 4 h, 14 h and 24 h. MTT assay was used to detect the quantification of the biofilms formed. The structures of biofilms were observed under confocal laser scanning microscopy after 24 h, and expression of biofilm-related genes (ftf, smu630, brpA, gbpB, gtfB, vicR, comDE and relA) was investigated by real-time PCR. Statistical analysis was performed with SPSS17.0 software package.<br><br>RESULTS: The results showed that biofilm formed by S. mutans(wild type strain, its luxS overexpression strain and luxS knockout strain) and L.acidophilus after 14 h were 0.481±0.024, 0.591±0.023 and 0.279±0.019, respectively. The same findings were present after 24 h, the biofilm formed by S.mutans overexpression strain with L.acidophilus was higher than wild type strain, and the biofilm formed by knockout strain significantly decreased; but there was no significant difference at 4 h time points. CLSM images revealed that both S.mutans overexpression strain and its wild type strain tended to aggregate into distinct clusters and dense structures, whereas the luxS knockout strain appeared relatively sparse. Compared with wild type strain, all of the genes examined were upregulated in the biofilms formed by the overexpression strain, and were downregulated in the biofilms formed by the luxS mutant strain in mixed-species biofilm.<br><br>CONCLUSIONS: S.mutans luxS gene can affect mixed-species biofilm formation with L.acidophilus, which provides evidences for further study.},
}
@article {pmid31382580,
year = {2019},
author = {Cattò, C and Cappitelli, F},
title = {Testing Anti-Biofilm Polymeric Surfaces: Where to Start?.},
journal = {International journal of molecular sciences},
volume = {20},
number = {15},
pages = {},
doi = {10.3390/ijms20153794},
pmid = {31382580},
issn = {1422-0067},
abstract = {Present day awareness of biofilm colonization on polymeric surfaces has prompted the scientific community to develop an ever-increasing number of new materials with anti-biofilm features. However, compared to the large amount of work put into discovering potent biofilm inhibitors, only a small number of papers deal with their validation, a critical step in the translation of research into practical applications. This is due to the lack of standardized testing methods and/or of well-controlled in vivo studies that show biofilm prevention on polymeric surfaces; furthermore, there has been little correlation with the reduced incidence of material deterioration. Here an overview of the most common methods for studying biofilms and for testing the anti-biofilm properties of new surfaces is provided.},
}
@article {pmid31382523,
year = {2019},
author = {Karampoula, F and Doulgeraki, AI and Fotiadis, C and Tampakaki, A and Nychas, GE},
title = {Monitoring Biofilm Formation and Microbial Interactions that May Occur During a Salmonella Contamination Incident across the Network of a Water Bottling Plant.},
journal = {Microorganisms},
volume = {7},
number = {8},
pages = {},
doi = {10.3390/microorganisms7080236},
pmid = {31382523},
issn = {2076-2607},
support = {380229//European Social Fund/ ; 548//Education and Lifelong Learning/ ; },
abstract = {The present study aims to monitor the ability of Salmonella to colonize and compete as a member of the mixed species biofilm within key points at a water bottling plant, in case of a contamination incident with this major foodborne pathogen. To achieve this goal, bacterial communities throughout the production line were collected and their identities were investigated by microbial counts and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). These bacterial communities alone or along with constructed Salmonellaenterica serovar Typhimurium (ST) fluorescence-based bioreporters were left to form a biofilm on stainless steel for 6 days at 20 °C. ST bioreporters were constructed by introducing plasmids expressing EYFP (enhanced yellow fluorescent protein) fusions of the genes csgB, csrA, sspH2, and fliD into ST 14028S. The bead vortexing-plate counting method was applied for the enumeration of the biofilm population, while the behavior of the bioreporters was evaluated by fluorescence microscopy. From a set of 16 samples that were collected from the plant, species of Citrobacter, Staphylococcus, Pseudomonas, Bacillus, and Exiguobacterium were identified. The presence of these indigenous bacteria neither inhibited nor enhanced the biofilm formation of ST in mixed bacterial communities (p > 0.05). Furthermore, the csrA-based bioreporter was shown to be induced in multispecies biofilms with Citrobacter. In conclusion, this study enhanced our knowledge of bacterial interactions occurring within a biofilm in a water bottling plant.},
}
@article {pmid31382160,
year = {2019},
author = {Martins, ML and Monteiro, ASN and Guimarães, JEC and Guimarães, MBCT and da Silva, RF and Cabral, LM and Farah, A and dePaula, J and Romanos, MTV and Maia, LC and Cavalcanti, YW and Fonseca-Gonçalves, A},
title = {Cytotoxic and antibacterial effect of a red propolis mouthwash, with or without fluoride, on the growth of a cariogenic biofilm.},
journal = {Archives of oral biology},
volume = {107},
number = {},
pages = {104512},
doi = {10.1016/j.archoralbio.2019.104512},
pmid = {31382160},
issn = {1879-1506},
abstract = {OBJECTIVE: To evaluatein vitro the antibacterial activity, the antibiofilm effect and the cytotoxic potential of mouthwashes containing Brazilian red propolis with or without fluoride.<br><br>METHODS: The minimum inhibitory and bactericidal concentrations (MIC and MBC) against S. mutans, S. sanguinis, S. salivarius and L. casei were determined for RPE mouthwashes. A cariogenic biofilm with the aforementioned bacteria was formed over cellulose membrane disks (N = 30, 13 mm), which were submitted for 1 min to the following mouthwashes: plain mouthwash base; 0.05% NaF; 0.8% RPE; 0.8% RPE + 0.05% NaF and 0.12% chlorhexidine (CHX). The bacterial viability and the production of extracellular polysaccharide (EPS) were measured. Cytotoxic potential of the mouthwashes was also evaluated. For bacterial viability and EPS production, Mann-Withney and one-way ANOVA tests were performed followed by Tukey, with results considered significant when p ≤ 0.05.<br><br>RESULTS: MIC and MBC values of RPE mouthwashes ranged from 7.44 to 29.76 mg/mL and from 7.44 to ≥59.52 mg/mL, respectively, presenting better action against S. salivarius. RPE mouthwashes showed 44% of viable cells after 1 min of contact with fibroblasts. RPE (7.74) had the greatest reduction of viable total microorganisms and did not differ from the RPE + NaF (7.95) (p = 0.292). CHX (7.54) was the most effective in reducing Streptococcus spp, but did not differ from RPE (p = 0.521) and RPE + NaF (p = 0.238). There was no difference between the treatments regarding EPS production.<br><br>CONCLUSION: RPE and RPE + NaF mouthwash showed similar antibacterial activity, toxicity level and antibiofilm effect compared to CHX.},
}
@article {pmid31380192,
year = {2019},
author = {Lei, W and Bruchmann, J and Rüping, JL and Levkin, PA and Schwartz, T},
title = {Biofilm Bridges Forming Structural Networks on Patterned Lubricant-Infused Surfaces.},
journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)},
volume = {6},
number = {13},
pages = {1900519},
doi = {10.1002/advs.201900519},
pmid = {31380192},
issn = {2198-3844},
abstract = {Despite many decades of research, biofilm architecture and spreading mechanisms are still not clear because of the heterogenous 3D structure within biofilms. Here, patterned &quot;slippery&quot; lubricant-infused porous surfaces are utilized to study biofilm structure of Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Staphylococcus aureus. It is found that bacteria are able to spread over bacteria-repellent lubricant-infused regions by using a mechanism, termed &quot;biofilm bridges&quot;. Here, it is demonstrated that bacteria use bridges to form interconnected networks between distant biofilm colonies. Detailed structure of bridges shows a spatial distribution of bacteria with an accumulation of respiratory active bacteria and biomass in the bridges. The core-shell structure of bridges formed by two-species mixed population is illustrated. It is demonstrated that eDNA and nutrients have a strong effect on biofilm bridges formation. Thus, it is believed that biofilm bridging is important to reveal the structure and communication within biofilms.},
}
@article {pmid31379772,
year = {2019},
author = {Josse, J and Valour, F and Maali, Y and Diot, A and Batailler, C and Ferry, T and Laurent, F},
title = {Interaction Between Staphylococcal Biofilm and Bone: How Does the Presence of Biofilm Promote Prosthesis Loosening?.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1602},
doi = {10.3389/fmicb.2019.01602},
pmid = {31379772},
issn = {1664-302X},
abstract = {With the aging of population, the number of indications for total joint replacement is continuously increasing. However, prosthesis loosening can happen and is related to two major mechanisms: (1) aseptic loosening due to prosthesis micromotion and/or corrosion and release of wear particles from the different components of the implanted material and (2) septic loosening due to chronic prosthetic joint infection (PJI). The &quot;aseptic&quot; character of prosthesis loosening has been challenged over the years, especially considering that bacteria can persist in biofilms and be overlooked during diagnosis. Histological studies on periprosthetic tissue samples reported that macrophages are the principle cells associated with aseptic loosening due to wear debris. They produce cytokines and favor an inflammatory environment that induces formation and activation of osteoclasts, leading to bone resorption and periprosthetic osteolysis. In PJIs, the presence of infiltrates of polymorphonuclear neutrophils is a major criterion for histological diagnosis. Neutrophils are colocalized with osteoclasts and zones of osteolysis. A similar inflammatory environment also develops, leading to bone resorption through osteoclasts. Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus lugdunensis are the main staphylococci observed in PJIs. They share the common feature to form biofilm. For S. aureus and S. epidermidis, the interaction between biofilm and immunes cells (macrophages and polymorphonuclear neutrophils) differs regarding the species. Indeed, the composition of extracellular matrix of biofilm seems to impact the interaction with immune cells. Recent papers also reported the major role of myeloid-derived suppressor cells in biofilm-associated PJIs with S. aureus. These cells prevent lymphocyte infiltration and facilitate biofilm persistence. Moreover, the role of T lymphocytes is still unclear and potentially underestimates. In this review, after introducing the cellular mechanism of aseptic and septic loosening, we will focus on the interrelationships between staphylococcal biofilm, immune cells, and bone cells.},
}
@article {pmid31378149,
year = {2019},
author = {Wang, W and Nemati, M},
title = {Co-biodegradation of naphthenic acids in anoxic denitrifying biofilm reactors.},
journal = {Environmental technology},
volume = {},
number = {},
pages = {1-17},
doi = {10.1080/09593330.2019.1650122},
pmid = {31378149},
issn = {1479-487X},
abstract = {Anoxic co-biodegradation of linear and cyclic naphthenic acids (NAs) namely octanoic acid, trans-4-methyl-1-cyclohexane carboxylic acid (trans-4MCHCA), cis- and trans-4-methyl-1-cyclohexane-acetic acids (cis-4MCHAA and trans-4MCHAA) was investigated in denitrifying biofilm reactors. In all evaluated compositions, co-biodegradation of NAs was coupled to denitrification, with octanoic acid showing the fastest biodegradation rate (1180.4 mg L-1 h-1 at loading rate of 1180.4 mg L-1 h-1), followed by trans-4MCHCA (398.1 mg L-1 h-1 at loading rate of 435.8 mg L-1 h-1), trans-4MCHAA (25.7 mg L-1 h-1 at loading rate of 221.7 mg L-1 h-1), and cis-4MCHAA (5.3 mg L-1 h-1 at loading rate of 16.9 mg L-1 h-1). Biodegradation of octanoic acid and trans-4MCHCA were not influenced by the presence of recalcitrant NAs (cis- and trans-4MCHAA). Co-biodegradation of cis- and trans-4MCHAA with octanoic acid, trans-4MCHCA, or their combination enhanced the biodegradability of these recalcitrant NAs, with the positive impact being more pronounced for trans-4MCHCA. Finally anoxic co-biodegradation of NAs under denitrifying conditions proceeded at rates that were faster than the aerobic rates obtained in similar mixtures. Anoxic biodegradation, therefore, is an effective alternative for in situ treatment of oil sands process water in anoxic stabilization ponds amended with nitrate, or as an ex situ treatment approach in denitrifying bioreactors whereby the cost and technical challenges of aeration are eliminated.},
}
@article {pmid31376667,
year = {2019},
author = {Li, X and Wang, X and Lee, DJ and Yan, WM},
title = {Highly heterogeneous interior structure of biofilm wastewater for enhanced pollutant removals.},
journal = {Bioresource technology},
volume = {291},
number = {},
pages = {121919},
doi = {10.1016/j.biortech.2019.121919},
pmid = {31376667},
issn = {1873-2976},
abstract = {Biofilm processes are widely used in wastewater treatment. The biofilm has highly heterogeneous interior structure, which can significantly affect the transport processes and the biological reactions over the biofilm. This study for the first time detailed the complicated velocity and concentration fields of substrate in a real biofilm structure. With a real biofilm interior being profiled and meshed to numerical solutions, the flow-through mode has significant distortion of inflow velocity fields and concentration distributions, which lead to enhanced biological reactions at regimes nearby major pores. Conversely, the crossflow mode depends weakly on the biofilm interior structure. The uniform biofilm model fails to describe the real biofilm processes. Future research needs based on real biofilm structures were discussed.},
}
@article {pmid31376126,
year = {2019},
author = {Kumari, S and Das, S},
title = {Expression of metallothionein encoding gene bmtA in biofilm-forming marine bacterium Pseudomonas aeruginosa N6P6 and understanding its involvement in Pb(II) resistance and bioremediation.},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11356-019-05916-2},
pmid = {31376126},
issn = {1614-7499},
support = {BT/PR14998/GBD/27/279/2010//Department of Biotechnology , Ministry of Science and Technology/ ; },
abstract = {The genetic basis and biochemical aspects of heavy metal endurance abilities have been precisely studied in planktonic bacteria; however, in nature, bacteria mostly grows as surface-attached communities called biofilms. A hallmark trait of biofilm is increased resistance to heavy metals compared with the resistance of planktonic bacteria. A proposed mechanism that contributes to this increased resistance is the enhanced expression of metal-resistant genes. bmtA gene coding for metallothionein protein is one such metal-resistant gene found in many bacterial spp. In the present study, lead (Pb) remediation potential of a biofilm-forming marine bacterium Pseudomonas aeruginosa N6P6 was explored. Biofilm-forming marine bacterium P. aeruginosa N6P6 possess bmtA gene and shows resistance towards many heavy metals, i.e., Pb, Cd, Hg, Cr, and Zn. The expression of metallothionein encoding gene bmtA is significantly high in 48-h-old biofilm culture (11. 4 fold) followed by 24-h-old biofilm culture of P. aeruginosa N6P6 (4.7 fold) (P < 0.05). However, in the case of planktonically grown culture of P. aeruginosa N6P6, the highest expression of bmtA gene was observed in 24-h-old culture. The expression of bmtA also increased significantly with increase in Pb concentration up to 800 ppm. CSLM analysis indicated significant reduction in the raw integrated density of biofilm-associated lipids and polysaccharides (PS) of P. aeruginosa N6P6 biofilm grown in Pb (sub-lethal concentration)-amended medium (P < 0.05), whereas no significant reduction was observed in the raw integrated density of EPS-associated protein. The role of bmtA gene as Pb(II)-resistant determinant was characterized by overexpressing the bmtA gene derived from P. aeruginosa N6P6 in Escherichia coli BL21(DE3). ESI-MS and SDS-PAGE analyses validated the presence of 11.5-kDa MT protein isolated from Pb(II)-induced recombinant E. coli BL21(DE3) harboring bmtA gene.},
}
@article {pmid31375964,
year = {2019},
author = {Fonseca, DL and Bassin, JP},
title = {Investigating the most appropriate methods for attached solids determination in moving-bed biofilm reactors.},
journal = {Bioprocess and biosystems engineering},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00449-019-02182-x},
pmid = {31375964},
issn = {1615-7605},
abstract = {Moving-bed biofilm reactors (MBBR) have been employed worldwide as an efficient technology for the treatment of a diverse set of wastewaters. Although the attached biomass represents the major fraction of solids in MBBR systems, there is still no standard for its reliable quantification. An extensive literature review indicated that several methods for attached biomass assessment are applied, hindering the comparability of results issued from different studies. Therefore, the most reported methods for biofilm quantification in the MBBR literature were compared using three different carriers. The results revealed that the performance of each method was biased depending on the carrier type and shape. Moreover, differences in total attached solids (TAS) concentrations varied from 13% up to more than 90%, depending on the employed method for a given carrier. Overall, direct weighing of the carrier containing the biofilm, accounting for the clean carrier weight, and manual extraction of the biofilm, preceded or not by sonication for at least 15 min, were the most suitable techniques for assessing TAS and the volatile/total solids ratio in non-porous medias, respectively. The results here presented may be used as a frame of reference for standardization of the methods for assessing the biofilm mass in MBBR carriers.},
}
@article {pmid31374264,
year = {2019},
author = {Sherly Carolyn, J and Selva Raj, D and Malaikozhundan, B and Govindarajan, M and Alharbi, NS and Kadaikunnan, S and Khaled, JM and Al-Anbr, MN and Alobaidi, AS and Vaseeharan, B},
title = {Anti-cancer, anti-biofilm, and anti-inflammatory properties of Hen's albumen: a photodynamic approach.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2019.07.026},
pmid = {31374264},
issn = {1873-1597},
abstract = {The albumen plays a major role in the protection of eggs against microorganisms. It contains an arsenal of natural antimicrobial molecules and antibacterial proteins, including the well-known ovotransferrin and lysozyme, which exert their activities against a range of bacteria. In the present study, the hen's albumen extract treated with the dried insect body of blister beetle M. pustulata was assessed for antibacterial, antibiofilm, anti-inflammatory and anti-proliferative activity. The zone of inhibition against Gram positive E. faecalis and S. aureus was 10.8 mm and 12.1 mm respectively at 100 µg mL-1. However, it was 13.6 mm and 15.3 mm for Gram negative P. aeruginosa and P. vulgaris respectively. The biofilm of tested bacteria was significantly inhibited at 100 µg mL-1. The hydrophobicity of bacterial biofilms was considerably condensed after treatment with the hen's albumen extracts at 100 µg mL-1. The anti-inflammatory activity of hen's albumen extracts was confirmed by the inhibition of cyclooxygenase (COX) enzyme to 84.91% at 100 μg mL-1 with the relative IC50 of 8.26 μg mL-1. The albumen extract effectively inhibited the viability (23.61%) of HepG2 hepatic cancer cells at 100 µg mL-1. The anti-proliferative activity of the albumen extracts was further revealed by the induction of HepG2 apoptotic cell morphology. This study concludes that the hen's albumen extract treated with M. pustulata is a natural therapeutic agent to treat biofilm associated clinical bacteria, inflammations and human hepatic cancer cells.},
}
@article {pmid31373891,
year = {2019},
author = {Bottino, MA and Pereira, S and Amaral, M and Milhan, N and Pereira, CA and Camargo, S and Carvalho, A and Melo, RM},
title = {Streptococcus mutans Biofilm Formation and Cell Viability on Polymer-infiltrated Ceramic and Yttria-stabilized Polycrystalline Zirconium Dioxide Ceramic.},
journal = {Operative dentistry},
volume = {},
number = {},
pages = {},
doi = {10.2341/18-278-L},
pmid = {31373891},
issn = {1559-2863},
abstract = {OBJECTIVE: The aim of this study was to investigate the biofilm formation and cell viability of a polymer-infiltrated ceramic (PIC) and an yttria-stabilized polycrystalline zirconium dioxide ceramic (Y-TZP). The null hypothesis was that there would be no difference in biofilm formation and cell viability between the materials.<br><br>METHODS AND MATERIALS: Streptococcus mutans biofilm was analyzed with scanning electron microscopy (SEM), confocal laser scanning microscopy, and colony counting (colony-forming units/mL). The cell viability (fibroblasts) of both materials was measured with 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium) (MTT) test. Roughness measurements were also performed.<br><br>RESULTS: The PIC displayed higher roughness but showed similar colony-forming units and biovolume values to those of Y-TZP. SEM showed a higher amount of adhered fibroblasts on the PIC surface on the first day and similar amounts on both materials after seven days. Moreover, the materials were biocompatible with human fibroblasts.<br><br>CONCLUSION: PIC and Y-TZP are biocompatible and present the same characteristics for biofilm formation; therefore, they are indicated for indirect restorations and implant abutments.},
}
@article {pmid31373035,
year = {2019},
author = {Simkins, JW and Stewart, PS and Codd, SL and Seymour, JD},
title = {Non-invasive imaging of oxygen concentration in a complex in vitro biofilm infection model using 19 F MRI: Persistence of an oxygen sink despite prolonged antibiotic therapy.},
journal = {Magnetic resonance in medicine},
volume = {82},
number = {6},
pages = {2248-2256},
doi = {10.1002/mrm.27888},
pmid = {31373035},
issn = {1522-2594},
support = {//National Science Foundation./ ; R01 GM109452/GM/NIGMS NIH HHS/United States ; R01GM109452/NH/NIH HHS/United States ; },
abstract = {PURPOSE: Oxygen availability is a critical determinant of microbial biofilm activity and antibiotic susceptibility. However, measuring oxygen gradients in these systems remains difficult, with the standard microelectrode approach being both invasive and limited to single-point measurement. The goal of the study was to develop a 19 F MRI approach for 2D oxygen mapping in biofilm systems and to visualize oxygen consumption behavior in real time during antibiotic therapy.<br><br>METHODS: Oxygen-sensing beads were created by encapsulating an emulsion of oxygen-sensing fluorocarbon into alginate gel. Escherichia coli biofilms were grown in and on the alginate matrix, which was contained inside a packed bed column subjected to nutrient flow, mimicking the complex porous structure of human wound tissue, and subjected to antibiotic challenge.<br><br>RESULTS: The linear relationship between 19 F spin-lattice relaxation rate R1 and local oxygen concentration permitted noninvasive spatial mapping of oxygen distribution in real time over the course of biofilm growth and subsequent antibiotic challenge. This technique was used to visualize persistence of microbial oxygen respiration during continuous gentamicin administration, providing a time series of complete spatial maps detailing the continued bacterial utilization of oxygen during prolonged chemotherapy in an in vitro biofilm model with complex spatial structure.<br><br>CONCLUSIONS: Antibiotic exposure temporarily causes oxygen consumption to enter a pseudosteady state wherein oxygen distribution becomes fixed; oxygen sink expansion resumes quickly after antibiotic clearance. This technique may provide valuable information for future investigations of biofilms by permitting the study of complex geometries (typical of in vivo biofilms) and facilitating noninvasive oxygen measurement.},
}
@article {pmid31372943,
year = {2019},
author = {Ansari, FA and Ahmad, I},
title = {Isolation, functional characterization and efficacy of biofilm-forming rhizobacteria under abiotic stress conditions.},
journal = {Antonie van Leeuwenhoek},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10482-019-01306-3},
pmid = {31372943},
issn = {1572-9699},
abstract = {Abiotic stresses such as salinity, drought and excessive heat are associated with significant loss of crop productivity globally, and require effective strategies for their reduction or tolerance. Biofilm-forming rhizobacteria, which harbor multifarious plant growth promoting traits and tolerance to abiotic stress, are believed to benefit plant health and production even under environmental stresses. The primary objective of this study was to investigate indigenous biofilm-forming rhizobacteria (Pseudomonas spp., Bacillus sp., Pantoea sp., Brevibacterium sp. and Acinetobacter sp.) for their functional diversity relevant to plant growth promoting activities, biofilm development and tolerance to abiotic stress conditions. The most promising isolates among FAP1, FAP2, FAP3, FAP4, FAP5, FAP10, FAB1, FAB3 and FAA1 were selected. Rhizobacteria exhibited high tolerance to salinity (1.5 M NaCl) and drought stress (up to 55% PEG-6000) conditions in vitro. The isolates demonstrated varying levels of PGP activities (IAA production and phosphate solubilization), biofilm development, and production of alginate and exopolysaccharides in the presence of salinity, drought stress and elevated temperature. Further efficacy of the isolates was demonstrated by inoculating to wheat (Triticum aestivum L.) plants in greenhouse conditions under both normal and drought stress for up to 30 days inoculation. The plant growth potential of the isolates was in the order of FAP3 > FAB3 > FAB1 > FAP10 > FAP5 > FAP4 > FAA1 > FAP2 > FAP1. The present study resulted in successful selection of promising PGPR as identified by 16S rRNA gene sequence analysis. Field study is needed to evaluate their relative performance in both 'normal' and stressed environments in order to be exploited for plant stress management.},
}
@article {pmid31371744,
year = {2019},
author = {Stępień-Pyśniak, D and Hauschild, T and Kosikowska, U and Dec, M and Urban-Chmiel, R},
title = {Biofilm formation capacity and presence of virulence factors among commensal Enterococcus spp. from wild birds.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {11204},
doi = {10.1038/s41598-019-47602-w},
pmid = {31371744},
issn = {2045-2322},
abstract = {Enterococci are opportunistic pathogens that can form biofilms during infections and many virulence determinants are involved in this process. Although the virulence factors are often analysed in Enterococcus spp. from humans and food animals, little is known about gut enterococcal isolates from wild birds. Therefore, the determination of virulence factors among enterococci isolated from wild birds may provide new information about a possible source of infection for humans and animals or vice versa via the environment. We analysed different phenotypic and genotypic traits in enterococci from wild birds related to potential virulence in humans and animals and to evaluate biofilm formation and its relationship to virulence genes. The E. faecalis isolates were characterised by greater frequency of biofilm formation in BHI than E. faecium. There was a correlation between hydrophobicity and biofilm formation in BHI broth in E. faecalis. None of the isolates was haemolytic. The presence of some adhesion and gelatinase genes was detected in biofilm-positive isolates. The enterococcal pathogenic factors (esp, hyl, and cyl operon genes) did not seem to be necessary or sufficient for production of biofilm by analysed bacteria. Enterococcus species isolated from wild birds should be considered as a possible source of some virulence determinants.},
}
@article {pmid31370119,
year = {2019},
author = {Song, YJ and Yu, HH and Kim, YJ and Lee, NK and Paik, HD},
title = {Anti-Biofilm Activity of Grapefruit Seed Extract against Staphylococcus aureus and Escherichia coli.},
journal = {Journal of microbiology and biotechnology},
volume = {29},
number = {8},
pages = {1177-1183},
doi = {10.1041/jmb.1905.05022},
pmid = {31370119},
issn = {1738-8872},
abstract = {Grapefruit seed extract (GSE) is a safe and effective preservative that is used widely in the food industry. However, there are few studies addressing the anti-biofilm effect of GSE. In this study, the anti-biofilm effect of GSE was investigated against biofilm-forming strains of Staphylococcus aureus and Escherichia coli. The GSE minimum inhibitory concentration (MIC) for S. aureus and E. coli were 25 μg/ml and 250 μg/ml, respectively. To investigate biofilm inhibition and degradation effect, crystal violet assay and stainless steel were used. Biofilm formation rates of four strains (S. aureus 7, S. aureus 8, E. coli ATCC 25922, and E. coli O157:H4 FRIK 125) were 55.8%, 70.2%, 55.4%, and 20.6% at 1/2 × MIC of GSE, respectively. The degradation effect of GSE on biofilms attached to stainless steel coupons was observed (≥ 1 log CFU/coupon) after exposure to concentrations above the MIC for all strains and 1/2 × MIC for S. aureus 7. In addition, the specific mechanisms of this anti-biofilm effect were investigated by evaluating hydrophobicity, auto-aggregation, exopolysaccharide (EPS) production rate, and motility. Significant changes in EPS production rate and motility were observed in both S. aureus and E. coli in the presence of GSE, while changes in hydrophobicity were observed only in E. coli. No relationship was seen between auto-aggregation and biofilm formation. Therefore, our results suggest that GSE might be used as an anti-biofilm agent that is effective against S. aureus and E. coli.},
}
@article {pmid31368074,
year = {2019},
author = {Zhou, JH and Yu, HC and Ye, KQ and Wang, HY and Ruan, YJ and Yu, JM},
title = {Optimized aeration strategies for nitrogen removal efficiency: application of end gas recirculation aeration in the fixed bed biofilm reactor.},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11356-019-06050-9},
pmid = {31368074},
issn = {1614-7499},
support = {51708499//National Natural Science Foundation of China/ ; 21576241//National Natural Science Foundation of China/ ; 21776262//National Natural Science Foundation of China/ ; 20180533B03//Hangzhou Agricultural and Social Development Research Program/ ; },
abstract = {Aeration strategy played an important role in reactor performance. In this study, when superficial upflow air velocity (SAV) decreased from 0.16 to 0.08 cm s-1, low dissolved oxygen concentration (DO) of 2.0 mg L-1 occurred in reactor. The required depth for anoxic microenvironment in biofilm decreased from 902.3 to 525.9 μm, which enhanced the growth of denitrifying bacteria and total nitrogen (TN) removal efficiency. However, decreasing aeration intensity resulted in insufficient hydraulic shear stress, which led to weak biofilm matrix structure. Mass biofilm detachment and reactor deterioration then occurred after 87 days of operation. An end gas recirculation aeration strategy was proposed to separately manipulate DO and aeration intensity. Low DO and high aeration intensity were simultaneously achieved, which enhanced the metabolism of denitrifying bacteria (such as Flavobacterium sp., Pseudorhodobacter sp., and Dok59 sp.) and EPS-producing bacteria (such as Zoogloea sp. and Rhodobacter sp.). Consequently, high TN removal performance (82.1 ± 2.7%) and stable biofilm structure were achieved.},
}
@article {pmid31366707,
year = {2019},
author = {Brown, JR and Jurcisek, J and Lakhani, V and Snedden, A and Ray, WC and Mokrzan, EM and Bakaletz, LO and Das, J},
title = {In Silico Modeling of Biofilm Formation by Nontypeable Haemophilus influenzae In Vivo.},
journal = {mSphere},
volume = {4},
number = {4},
pages = {},
doi = {10.1128/mSphere.00254-19},
pmid = {31366707},
issn = {2379-5042},
support = {R01 DC003915/NIDCD NIH HHS/National Institute on Deafness and Other Communication Disorders/United States ; R01 GM103612/NIGMS NIH HHS/National Institute of General Medical Sciences/United States ; },
abstract = {Biofilms formed by nontypeable Haemophilus influenzae (NTHI) bacteria play an important role in multiple respiratory tract diseases. Visual inspection of the morphology of biofilms formed during chronic infections shows distinct differences from biofilms formed in vitro To better understand these differences, we analyzed images of NTHI biofilms formed in the middle ears of Chinchilla lanigera and developed an in silico agent-based model of the formation of NTHI biofilms in vivo We found that, as in vitro, NTHI bacteria are organized in self-similar patterns; however, the sizes of NTHI clusters in vivo are more than 10-fold smaller than their in vitro counterparts. The agent-based model reproduced these patterns and suggested that smaller clusters occur due to elimination of planktonic NTHI cells by the host responses. Estimation of model parameters by fitting simulation results to imaging data showed that the effects of several processes in the model change during the course of the infection.IMPORTANCE Multiple respiratory illnesses are associated with formation of biofilms within the human airway by NTHI. However, a substantial amount of our understanding of the mechanisms that underlie NTHI biofilm formation is obtained from in vitro studies. Our in silico model that describes biofilm formation by NTHI within the middle ears of Chinchilla lanigera will help isolate processes potentially responsible for the differences between the morphologies of biofilms formed in vivo versus those formed in vitro Thus, the in silico model can be used to glean mechanisms that underlie biofilm formation in vivo and connect those mechanisms to those obtained from in vitro experiments. The in silico model developed here can be extended to investigate potential roles of specific host responses (e.g., mucociliary clearance) on NTHI biofilm formation in vivo The developed computational tools can also be used to analyze and describe biofilm formation by other bacterial species in vivo.},
}
@article {pmid31366705,
year = {2019},
author = {Kean, R and Ramage, G},
title = {Combined Antifungal Resistance and Biofilm Tolerance: the Global Threat of Candida auris.},
journal = {mSphere},
volume = {4},
number = {4},
pages = {},
doi = {10.1128/mSphere.00458-19},
pmid = {31366705},
issn = {2379-5042},
abstract = {The enigmatic yeast Candida auris has emerged over the last decade and rapidly penetrated our consciousness. The global threat from this multidrug-resistant yeast has generated a call to arms from within the medical mycology community. Over the past decade, our understanding of how this yeast has spread globally, its clinical importance, and how it tolerates and resists antifungal agents has expanded. This review highlights the clinical importance of antifungal resistance in C. auris and explores our current understanding of the mechanisms associated with azole, polyene, and echinocandin resistance. We also discuss the impact of phenotypic tolerance, with particular emphasis on biofilm-mediated resistance, and present new pipelines of antifungal drugs that promise new hope in the management of C. auris infection.},
}
@article {pmid31366076,
year = {2019},
author = {Ghensi, P and Bettio, E and Maniglio, D and Bonomi, E and Piccoli, F and Gross, S and Caciagli, P and Segata, N and Nollo, G and Tessarolo, F},
title = {Dental Implants with Anti-Biofilm Properties: A Pilot Study for Developing a New Sericin-Based Coating.},
journal = {Materials (Basel, Switzerland)},
volume = {12},
number = {15},
pages = {},
doi = {10.3390/ma12152429},
pmid = {31366076},
issn = {1996-1944},
support = {Prot. 24/2015//SIdP (Italian Society of Periodontology and Implantology)/ ; },
abstract = {AIM: several strategies have been tested in recent years to prevent bacterial colonization of dental implants. Sericin, one of the two main silk proteins, possesses relevant biological activities and also literature reports about its potential antibacterial properties, but results are discordant and not yet definitive. The aim of this study was to evaluate the effectiveness of different experimental protocols in order to obtain a sericin-based coating on medical grade titanium (Ti) able to reduce microbial adhesion to the dental implant surface.<br><br>MATERIALS AND METHODS: different strategies for covalent bonding of sericin to Ti were pursued throughout a multi-step procedure on Ti-6Al-4V disks. The surface of grade 5 Ti was initially immersed in NaOH solution to obtain the exposure of functional -OH groups. Two different silanization strategies were then tested using aminopropyltriethoxysilane (APTES). Eventually, the bonding between silanized Ti-6Al-4V and sericin was obtained with two different crosslinking processes: glutaraldehyde (GLU) or carbodiimide/N-Hydroxy-succinimide (EDC/NHS). Micro-morphological and compositional analyses were performed on the samples at each intermediate step to assess the most effective coating strategy able to optimize the silanization and bioconjugation processes. Microbiological tests on the coated Ti-6Al-4V disks were conducted in vitro using a standard biofilm producer strain of Staphylococcus aureus (ATCC 6538) to quantify the inhibition of microbial biofilm formation (anti-biofilm efficacy) at 24 hours.<br><br>RESULTS: both silanization techniques resulted in a significant increase of silicon (Si) on the Ti-6Al-4V surfaces etched with NaOH. Differences were found between GLU and EDC/NHS bioconjugation strategies in terms of composition, surface micro-morphology and anti-biofilm efficacy. Ti-6Al-4V samples coated with GLU-bound sericin after silanization obtained via vapor phase deposition proved that this technique is the most convenient and effective coating strategy, resulting in a bacterial inhibition of about 53% in respect to the uncoated Ti-6Al-4V disks.<br><br>CONCLUSIONS: The coating with glutaraldehyde-bound sericin after silanization in the vapor phase showed promising bacterial inhibition values with a significant reduction of S. aureus biofilm. Further studies including higher number of replicates and more peri-implant-relevant microorganisms are needed to evaluate the applicability of this experimental protocol to dental implants.},
}
@article {pmid31364079,
year = {2019},
author = {Lora-Tamayo, J and Murillo, O and Ariza, J},
title = {Clinical Use of Colistin in Biofilm-Associated Infections.},
journal = {Advances in experimental medicine and biology},
volume = {1145},
number = {},
pages = {181-195},
doi = {10.1007/978-3-030-16373-0_13},
pmid = {31364079},
issn = {0065-2598},
abstract = {Biofilm is an adaptive bacterial strategy whereby microorganisms become encased in a complex glycoproteic matrix. The low concentration of oxygen and nutrients in this environment leads to heterogeneous phenotypic changes in the bacteria, with antimicrobial tolerance being of paramount importance. As with other antibiotics, the activity of colistin is impaired by biofilm-embedded bacteria. Therefore, the recommendation for administering high doses in combination with a second drug, indicated for planktonic infections, remains valid in this setting. Notably, colistin has activity against metabolically inactive biofilm-embedded cells located in the inner layers of the biofilm structure. This is opposite and complementary to the activity of other antimicrobials that are able to kill metabolically active cells in the outer layers of the biofilm. Several experimental models have shown a higher activity of colistin when used in combination with other agents, and have reported that this can avoid the emergence of colistin-resistant subpopulations. Most experience of colistin in biofilm-associated infections comes from patients with cystic fibrosis, where the use of nebulized colistin allows high concentrations to reach the site of the infection. However, limited clinical experience is available in other scenarios, such as osteoarticular infections or device-related central nervous system infections caused by multi-drug resistant microorganisms. In the latter scenario, the use of intraventricular or intrathecal colistin also permits high local concentrations and good clinical results. Overall, the efficacy of intravenous colistin seems to be poor, but its association with a second antimicrobial significantly increases the response rate. Given its activity against inner bioflm-embedded cells, its possible role in combination with other antibiotics, beyond last-line therapy situations, should be further explored.},
}
@article {pmid31363870,
year = {2019},
author = {Piotrowski, M and Wultańska, D and Obuch-Woszczatyński, P and Pituch, H},
title = {Fructooligosaccharides and mannose affect Clostridium difficile adhesion and biofilm formation in a concentration-dependent manner.},
journal = {European journal of clinical microbiology &amp; infectious diseases : official publication of the European Society of Clinical Microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10096-019-03635-7},
pmid = {31363870},
issn = {1435-4373},
support = {UMO:2017/25/N/NZ6/01763//Narodowe Centrum Nauki/ ; },
abstract = {The aim of this study was to investigate the effects that prebiotic and candidates for prebiotics on Clostridium difficile strains to adhere to various human epithelial cell lines and to compare the adhesive properties of specific C. difficile strains. We also sought to examine the effect of different concentrations of fructooligosaccharides and mannose on the formation of biofilms by C. difficile strains. The influence of cellobiose, fructooligosaccharides, inulin, mannose, and raffinose on the adherence properties of various C. difficile strains, including motile 630, non-motile M120, and 10 clinical motile ribotype 027 strains, to non-mucous secreting HT-29, mucous secreting HT-29 MXT, and CCD 841 CoN cells lines. The most effective prebiotics were used in biofilm formation assays. We demonstrated that all C. difficile strains adhered to all cell lines. However, the C. difficile M120 non-motile strain was statistically more likely to adhere to all three cell lines (CFU median, 40) compared to the motile strains (CFU median, 3; p < 0.001). Furthermore, among the carbohydrates examined, only fructooligosaccharides and mannose were found to significantly decrease adhesion (p < 0.001) of C. difficile strains. Alternatively, using a biofilm assay, we observed, via confocal laser scanning microscopy, that sub-inhibitory concentrations (1%) of fructooligosaccharides and mannose functioned to increase biofilm formation by C. difficile. We demonstrated that specific prebiotics and candidate prebiotics exhibit varying anti-adhesive properties towards C. difficile in vitro and that treatment with sub-inhibitory concentrations of prebiotics can cause an increase in biofilm formation by C. difficile.},
}
@article {pmid31363032,
year = {2019},
author = {Orazi, G and Ruoff, KL and O'Toole, GA},
title = {Pseudomonas aeruginosa Increases the Sensitivity of Biofilm-Grown Staphylococcus aureus to Membrane-Targeting Antiseptics and Antibiotics.},
journal = {mBio},
volume = {10},
number = {4},
pages = {},
doi = {10.1128/mBio.01501-19},
pmid = {31363032},
issn = {2150-7511},
support = {R37 AI083256/NIAID NIH HHS/National Institute of Allergy and Infectious Diseases Extramural Activities/United States ; T32 AI007519/NIAID NIH HHS/National Institute of Allergy and Infectious Diseases Extramural Activities/United States ; },
abstract = {Pseudomonas aeruginosa and Staphylococcus aureus often cause chronic, recalcitrant infections in large part due to their ability to form biofilms. The biofilm mode of growth enables these organisms to withstand antibacterial insults that would effectively eliminate their planktonic counterparts. We found that P. aeruginosa supernatant increased the sensitivity of S. aureus biofilms to multiple antimicrobial compounds, including fluoroquinolones and membrane-targeting antibacterial agents, including the antiseptic chloroxylenol. Treatment of S. aureus with the antiseptic chloroxylenol alone did not decrease biofilm cell viability; however, the combination of chloroxylenol and P. aeruginosa supernatant led to a 4-log reduction in S. aureus biofilm viability compared to exposure to chloroxylenol alone. We found that the P. aeruginosa-produced small molecule 2-n-heptyl-4-hydroxyquinoline N-oxide (HQNO) is responsible for the observed heightened sensitivity of S. aureus to chloroxylenol. Similarly, HQNO increased the susceptibility of S. aureus biofilms to other compounds, including both traditional and nontraditional antibiotics, which permeabilize bacterial membranes. Genetic and phenotypic studies support a model whereby HQNO causes an increase in S. aureus membrane fluidity, thereby improving the efficacy of membrane-targeting antiseptics and antibiotics. Importantly, our data show that P. aeruginosa exoproducts can enhance the ability of various antimicrobial agents to kill biofilm populations of S. aureus that are typically difficult to eradicate. Finally, our discovery that altering membrane fluidity shifts antimicrobial sensitivity profiles of bacterial biofilms may guide new approaches to target persistent infections, such as those commonly found in respiratory tract infections and in chronic wounds.IMPORTANCE The thick mucus in the airways of cystic fibrosis (CF) patients predisposes them to frequent, polymicrobial respiratory infections. Pseudomonas aeruginosa and Staphylococcus aureus are frequently coisolated from the airways of individuals with CF, as well as from diabetic foot ulcers and other wounds. Both organisms form biofilms, which are notoriously difficult to eradicate and promote chronic infection. In this study, we have shown that P. aeruginosa-secreted factors can increase the efficacy of compounds that alone have little or no bactericidal activity against S. aureus biofilms. In particular, we discovered that P. aeruginosa exoproducts can potentiate the antistaphylococcal activity of phenol-based antiseptics and other membrane-active drugs. Our findings illustrate that polymicrobial interactions can dramatically increase antibacterial efficacy in vitro and suggest that altering membrane physiology promotes the ability of certain drugs to kill bacterial biofilms-knowledge that may provide a path for the discovery of new biofilm-targeting antimicrobial strategies.},
}
@article {pmid31362660,
year = {2019},
author = {Jain, N and Mansuri, A},
title = {Stopping the Unstoppable: Unconventional methods to prevent biofilm growth.},
journal = {Current drug discovery technologies},
volume = {},
number = {},
pages = {},
doi = {10.2174/1570163816666190726153441},
pmid = {31362660},
issn = {1875-6220},
abstract = {Biofilms are consortia of microorganisms encased in extracellular matrix that protect cells from adverse conditions. A biofilm matrix is typically composed of extracellular DNA, cellulose and proteinaceous amyloid fibers. The matrix aids in adhesion to abiotic and biotic surface including medical devices and host tissues. Presence of biofilm makes bacteria more resilient and non-responsive to most current treatment regimes at disposal. Therefore, biofilm-associated infections are serious threat in hospital settings and pose a huge burden on economy. Inhibition of matrix components (cellulose and/or amyloid formation) has emerged as a lucrative alternative strategy to cure biofilm-related infections and combat antibiotic resistance. Here we review the current and emerging therapeutic interventions to mitigate persistent infections due to biofilms. The successful implementation of these interventions will have a huge impact on alleviating the current financial burden on healthcare services.},
}
@article {pmid31362602,
year = {2019},
author = {Hirayama, S and Nojima, N and Furukawa, S and Ogihara, H and Morinaga, Y},
title = {Steric microstructure of mixed-species biofilm formed by interaction between Lactobacillus plantarum ML11-11 and Saccharomyces cerevisiae.},
journal = {Bioscience, biotechnology, and biochemistry},
volume = {},
number = {},
pages = {1-4},
doi = {10.1080/09168451.2019.1649978},
pmid = {31362602},
issn = {1347-6947},
abstract = {The mixed-species biofilm of Lactobacillus plantarum ML11-11 (LAB) and yeast had a double-layered structure with the ground layer composed of LAB cells, and the upper layer composed of coaggregates of LAB and yeast cells. The ability of LAB to adhere to both, the solid surface and the yeast cells, enabled the formation and maintenance of the biofilm as an ecosystem for LAB and yeast.},
}
@article {pmid31362224,
year = {2019},
author = {Ashkanani, A and Almomani, F and Khraisheh, M and Bhosale, R and Tawalbeh, M and AlJaml, K},
title = {Bio-carrier and operating temperature effect on ammonia removal from secondary wastewater effluents using moving bed biofilm reactor (MBBR).},
journal = {The Science of the total environment},
volume = {693},
number = {},
pages = {133425},
doi = {10.1016/j.scitotenv.2019.07.231},
pmid = {31362224},
issn = {1879-1026},
abstract = {This study investigates the impact of bio-carriers' surface area and shape, wastewater chemistry and operating temperature on ammonia removal from real wastewater effluents using Moving bed biofilm reactors (MBBRs) operated with three different AnoxKaldness bio-carriers (K3, K5, and M). The study concludes the surface area loading rate, specific surface area, and shape of bio-carrier affect ammonia removal under real conditions. MBBR kinetics and sensitivity for temperature changes were affected by bio-carrier type. High surface area bio-carriers resulted in low ammonia removal and bio-carrier clogging. Significant ammonia removals of 1.420 ± 0.06 and 1.103 ± 0.06 g - N/m2. d were achieved by K3(As = 500 m2/m3) at 35 and 20 °C, respectively. Lower removals were obtained by high surface area bio-carrier K5 (1.123 ± 0.06 and 0.920 ± 0.06 g - N/m2. d) and M (0.456 ± 0.05 and 0.295 ± 0.05 g - N/m2. d) at 35 and 20 °C, respectively. Theta model successfully represents ammonia removal kinetics with θ values of 1.12, 1.06 and 1.13 for bio-carrier K3, K5 and M respectively. MBBR technology is a feasible choice for treatment of real wastewater effluents containing high ammonia concentrations.},
}
@article {pmid31362109,
year = {2019},
author = {Sayar, F and Chiniforush, N and Bahador, A and Etemadi, A and Akhondi, N and Azimi, C},
title = {Efficacy of antimicrobial photodynamic therapy for elimination of Aggregatibacter actinomycetemcomitans biofilm on Laser-Lok titanium discs.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {27},
number = {},
pages = {462-466},
doi = {10.1016/j.pdpdt.2019.07.012},
pmid = {31362109},
issn = {1873-1597},
abstract = {BACKGROUND: Antimicrobial Photodynamic therapy (aPDT) is a novel modality suggested for treatment of peri-implantitis. This study aimed to assess the effect of aPDT with toluidine blue (TBO) and indocyanine green (ICG) and 635 nm and 808 nm diode laser on Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) biofilm formed on Laser-Lok titanium discs.<br><br>MATERIALS AND METHODS: Eighty sterile Laser-Lok titanium discs were inoculated with A. actinomycetemcomitans to form biofilm and were randomly divided into 8 groups (n = 10) of control, chlorhexidine (CHX), TBO, ICG, 635 nm diode laser with 220 mW power, 808 nm diode laser with 250 mW power, 100 μg/mL TBO+635 nm diode laser and ICG+808 nm diode laser. Number of colony forming units (CFUs) on the surface of each disc was counted after the intervention. Data were analyzed using the Kruskal-Wallis test.<br><br>RESULTS: Significant differences were noted in colony count among the eight groups after the intervention (P = 0.001). Pairwise comparisons with adjusted P value test showed that aPDT with TBO+635 nm laser and ICG+808 nm laser caused significant reduction of bacterial biofilm compared to the control group (P = 0.0001). TBO alone caused significant reduction of biofilm compared to the control group (P = 0.004). No other significant differences were noted (P > 0.05).<br><br>CONCLUSION: Within the limitations of this study, the results showed that aPDT is a potential modality for decontamination of implant surface and reduction of A. actinomycetemcomitans biofilm in vitro. In this study, aPDT with TBO+635 nm diode laser and ICG+808 nm diode laser decreased the bacterial load on titanium discs.},
}
@article {pmid31360725,
year = {2019},
author = {Leonhard, M and Zatorska, B and Moser, D and Schneider-Stickler, B},
title = {Growth Media for Mixed Multispecies Oropharyngeal Biofilm Compositions on Silicone.},
journal = {BioMed research international},
volume = {2019},
number = {},
pages = {8051270},
doi = {10.1155/2019/8051270},
pmid = {31360725},
issn = {2314-6141},
abstract = {Aims: Microbial colonization of silicone voice prostheses by bacteria and Candida species limits the device lifetime of modern voice prostheses in laryngectomized patients. Thus, research focuses on biofilm inhibitive properties of novel materials, coatings, and surface enhancements. Goal of this in vitro study was the evaluation of seven commonly used growth media to simulate growth of mixed oropharyngeal species as mesoscale biofilms on prosthetic silicone for future research purposes.<br><br>Methods and Results: Yeast Peptone Dextrose medium (YPD), Yeast Nitrogen Base medium (YNB), M199 medium, Spider medium, RPMI 1640 medium, Tryptic Soy Broth (TSB), and Fetal Bovine Serum (FBS) were used to culture combined mixed Candida strains and mixed bacterial-fungal compositions on silicone over the period of 22 days. The biofilm surface spread and the microscopic growth showed variations from in vivo biofilms depending on the microbial composition and growth medium.<br><br>Conclusion: YPD and FBS prove to support continuous in vitro growth of mixed bacterial-fungal oropharyngeal biofilms deposits over weeks as needed for longterm in vitro testing with oropharyngeal biofilm compositions.<br><br>The study provides data on culture conditions for mixed multispecies biofilm compositions that can be used for future prosthesis designs.},
}
@article {pmid31357945,
year = {2019},
author = {Ramos, JN and Souza, C and Faria, YV and da Silva, EC and Veras, JFC and Baio, PVP and Seabra, SH and de Oliveira Moreira, L and Hirata Júnior, R and Mattos-Guaraldi, AL and Vieira, VV},
title = {Bloodstream and catheter-related infections due to different clones of multidrug-resistant and biofilm producer Corynebacterium striatum.},
journal = {BMC infectious diseases},
volume = {19},
number = {1},
pages = {672},
doi = {10.1186/s12879-019-4294-7},
pmid = {31357945},
issn = {1471-2334},
abstract = {BACKGROUND: Corynebacterium striatum is an emerging multidrug-resistant (MDR) pathogen associated with immunocompromised and chronically ill patients, as well as nosocomial outbreaks. In this study, we characterized 23 MDR C. striatum isolated of bloodstream and catheter-related infections from a hospital of Rio de Janeiro.<br><br>METHODS: C. striatum isolates were identified by 16S rRNA and rpoB genes sequencing. The dissemination of these isolates was accomplished by pulsed-field gel electrophoresis (PFGE). All isolates were submitted to antimicrobial susceptibility testing by disk diffusion and by minimum inhibitory concentration using E-test strips methods. Antimicrobial resistance genes were detected by polymerase chain reaction. Quantitative tests were performed on four different abiotic surfaces and the ability to produce biofilm on the surface of polyurethane and silicone catheter was also demonstrated by scanning electron microscopy.<br><br>RESULTS: Eleven PFGE profiles were found. The PFGE profile I was the most frequently observed among isolates. Five different MDR profiles were found and all PFGE profile I isolates presented susceptibility only to tetracycline, vancomycin, linezolid and daptomycin. Only the multidrug-susceptible isolate did not show mutations in the quinolone-resistance determinant region (QRDR) of the gyrA gene and was negative in the search of genes encoding antibiotic resistance. The other 22 isolates were positive to resistance genes to aminoglycoside, macrolides/lincosamides and chloramphenicol and showed mutations in the QRDR of the gyrA gene. Scanning electron microscopy illustrated the ability of MDR blood isolate partaker of the epidemic clone (PFGE profile I) to produce mature biofilm on the surface of polyurethane and silicone catheter.<br><br>CONCLUSIONS: Genotyping analysis by PFGE revealed the permanence of the MDR PFGE profile I in the nosocomial environment. Other new PFGE profiles emerged as etiologic agents of invasive infections. However, the MDR PFGE profile I was also found predominant among patients with hematogenic infections. The high level of multidrug resistance associated with biofilm formation capacity observed in MDR C. striatum is a case of concern.},
}
@article {pmid31357240,
year = {2019},
author = {Feng, G and Cheng, Y and Worobo, RW and Borca-Tasciuc, DA and Moraru, CI},
title = {Nanoporous anodic alumina reduces Staphylococcus biofilm formation.},
journal = {Letters in applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/lam.13201},
pmid = {31357240},
issn = {1472-765X},
abstract = {Staphylococcus epidermidis and Staphylococcus aureus, two bacterial strains commonly associated with biofilm-related medical infections and food poisoning, can rapidly colonize biotic and abiotic surfaces. The present study investigates the ability of anodic alumina surfaces with nanoporous surface topography to minimize the attachment and biofilm formation mediated by these pathogenic bacterial strains. Early attachment and subsequent biofilm development were retarded on surfaces with nanopores of 15-25 nm in diameter compared to surfaces with 50-100 nm pore diameter and nanosmooth surfaces. After 30 min of incubation in nutritive media, the biomass accumulation per unit surface area was 2·93 ± 1·72 μm3 μm-2 for the 15 nm, 3·49 ± 1·97 μm3 μm-2 for the 25 nm, as compared to 14·04 ± 6·39 μm3 μm-2 for the nanosmooth, 11·88 ± 9·72 μm3 μm-2 for the 50 nm, and 12·09 ± 11·84 μm3 μm-2 for the 100 nm surfaces, respectively. These findings suggest that anodic alumina with small size nanoscale pores could reduce the incidence of staphylococcal biofilms and infections, and shows promise as a material for a variety of medical applications and food contact surfaces. This article is protected by copyright. All rights reserved.},
}
@article {pmid31356873,
year = {2019},
author = {Lee, HH and Del Pozzo, J and Salamanca, SA and Hernandez, H and Martinez, LR},
title = {Reduced phagocytosis and killing of Cryptococcus neoformans biofilm-derived cells by J774.16 macrophages is associated with fungal capsular production and surface modification.},
journal = {Fungal genetics and biology : FG &amp; B},
volume = {132},
number = {},
pages = {103258},
doi = {10.1016/j.fgb.2019.103258},
pmid = {31356873},
issn = {1096-0937},
support = {R01 AI145559/AI/NIAID NIH HHS/United States ; },
abstract = {Cryptococcus neoformans is an opportunistic encapsulated pathogen that causes life-threatening meningoencephalitis in individuals with immunosuppression. We compared the interactions of C. neoformans planktonic and biofilm-derived cells with J774.16 macrophage-like cells. Planktonic cells are more phagocytized and killed by J774.16 cells than biofilm-derived fungal cells. Biofilm-derived cryptococci possess larger capsule size and release significantly more capsular polysaccharide than planktonic cells in culture. Biofilm-derived fungi exhibited upregulation of genes involved in capsular production. Capsular-specific monoclonal antibody 18B7 demonstrated differential binding to the surface of planktonic and biofilm-derived cryptococci providing a plausible strategy for fungal evasion of macrophages and persistence. Future studies are necessary to elucidate how C. neoformans biofilm-derived cells regulate their virulence factors when interacting with cells of the immune system.},
}
@article {pmid31355999,
year = {2019},
author = {Chuang, PJ and Swaminathan, V and Pavlovsky, L and Marquez-Catral, L and Jones, DL and Song, L},
title = {Negative influence of biofilm on CoCrMo corrosion.},
journal = {Journal of biomedical materials research. Part A},
volume = {107},
number = {11},
pages = {2556-2566},
doi = {10.1002/jbm.a.36761},
pmid = {31355999},
issn = {1552-4965},
abstract = {Minimal studies exist investigating biofilm-induced corrosion of orthopaedic implants. This study investigates potential contributions of Pseudomonas aeruginosa and Staphylococcus aureus biofilms on corrosion resistance of CoCrMo under static and fretting conditions. Biofilms were cultured on CoCrMo coupons for either 4 weeks (static culture) or 6 days (fretting culture; pin-on-disk with a Ti6Al4V hemispherical tip pin). Morphology of biofilms and corrosion of coupon surfaces were analyzed via SEM. Open circuit potential and electrochemical impedance spectroscopy measurements were collected for corrosion performance evaluation. Results showed no visible corrosion on coupon surfaces in static culture, which suggests these biofilms alone do not induce severe corrosion under the conditions of this study. However, electrochemical data showed biofilm presence lowered coupon electrochemical impedance in static and fretting cultures, suggesting resistive and capacitive characteristics of the metal oxide-biofilm-media interface were altered. Under fretting, the P. aeruginosa group exhibited a distinct damage morphology and Co:Cr:Mo ratio within the wear scar when compared with S. aureus and the bacteria-free control. These differences suggest the presence of P. aeruginosa biofilms may negatively impact corrosion resistance at the fretting interface. Taken together these results demonstrate biofilms can contribute to implant corrosion by influencing the electrochemical impedance of implant metal surfaces.},
}
@article {pmid31354823,
year = {2019},
author = {Cunha, EJ and Auersvald, CM and Deliberador, TM and Gonzaga, CC and Esteban Florez, FL and Correr, GM and Storrer, CLM},
title = {Effects of Active Oxygen Toothpaste in Supragingival Biofilm Reduction: A Randomized Controlled Clinical Trial.},
journal = {International journal of dentistry},
volume = {2019},
number = {},
pages = {3938214},
doi = {10.1155/2019/3938214},
pmid = {31354823},
issn = {1687-8728},
abstract = {Gingivitis is still considered a major risk factor for the occurrence and progression of periodontal disease. The aim of the present study was to compare the long-term (1, 12, and 18 weeks) antiplaque and antigingivitis efficacies of two commercially available toothpastes, Colgate Total® (CT) and BlueM® (BM), against attached supragingival dental plaque and gingival inflammation in an experimental gingivitis model. A parallel double-blinded randomized clinical trial including 39 dental students who refrained from all plaque control methods (manual or chemical) for 7 days was conducted. After the establishment of clinical gingivitis, participants were randomized into two experimental groups (CT and BM). Plaque index (PI) and gingival index (GI) were then calculated according to Turesky's modified Quigley and Hein index. Participants were assessed in four time periods (preclinical trial phase (W -1), gingivitis phase (W0), one week (W1), twelve weeks (W12), and eighteen weeks (W18)). Participants' stimulated saliva was collected and cultured (either aerobically or anaerobically, 37°C, 48 hours) in each time period (W -1, W0, W1, W12, and W18) for the count of viable colonies. Obtained data were analyzed using 2-way ANOVA and Tukey's test (α = 0.05). No significant differences were found (p > 0.05) between experimental groups at W -1. Significant differences between groups were observed at W0 (p < 0.05) for the parameter time period, but not for the interaction between parameters (time period ∗ toothpastes). Lower bacterial counts were observed in both groups after one week of toothbrushing; however, no significant differences were found between investigated dentifrices. Intra- and intergroup comparisons revealed that significant differences were not found (p > 0.05) between dentifrices at W1, W12, and W18 for both GI and PI. The present study demonstrated that toothpastes containing active oxygen and lactoferrin (BM) have comparable antiplaque and antigingivitis efficacies with triclosan-containing toothpastes (CT).},
}
@article {pmid31354319,
year = {2019},
author = {Abd El-Baky, RM and Sandle, T and John, J and Abuo-Rahma, GEA and Hetta, HF},
title = {A novel mechanism of action of ketoconazole: inhibition of the NorA efflux pump system and biofilm formation in multidrug-resistant Staphylococcus aureus.},
journal = {Infection and drug resistance},
volume = {12},
number = {},
pages = {1703-1718},
doi = {10.2147/IDR.S201124},
pmid = {31354319},
issn = {1178-6973},
abstract = {Background: The rapid emergence of antimicrobial resistance among Gram-positive organisms, especially staphylococci, has become a serious clinical challenge. Efflux machinery and biofilm formation are considered two of the main causes of antimicrobial resistance and therapy failure. Aim: Our study aims to evaluate the antibiofilm and efflux pump inhibitory activity of the antifungal ketoconazole against multidrug-resistant (MDR) Staphylococcus aureus. Methods: Ketoconazole was tested for its effect on the following: minimum inhibitory concentrations (MICs) of ciprofloxacin, norfloxacin, levofloxacin, and ethidium bromide (EtBr) by the broth microdilution method, the efflux of EtBr by NorA-positive MDR S. aureus, and the relative expression of NorA, NorB, and NorC efflux pump genes. Docking studies of ketoconazole were performed using 1PW4 (glycerol-3-phosphate transporter from Escherichia coli which was the representative structure from the major facilitator superfamily). Results: Ketoconazole significantly decreased the MICs of levofloxacin, ciprofloxacin, norfloxacin, and EtBr (a substrate for efflux pump) by 8 to 1024-fold (P<0.01) and decreased the efflux of EtBr. Furthermore, a time-kill assay revealed that combinations of levofloxacin with ketoconazole or carbonyl cyanide m-chlorophenylhydrazone showed no growth for the tested strains after 24 h in comparison to the effect of levofloxacin alone. Docking studies and the ability of ketoconazole to diminish the relative expression of NorA gene in comparison to control (untreated strains) confirmed its action as an efflux pump inhibitor. Conclusion: The findings showed that the antifungal ketoconazole has no antibacterial activity but can potentiate the activity of the fluroquinolones against MDR S. aureus via inhibiting efflux pump and biofilm formation in vitro.},
}
@article {pmid31352165,
year = {2019},
author = {Riegler, P and Bieringer, E and Chrusciel, T and Stärz, M and Löwe, H and Weuster-Botz, D},
title = {Continuous conversion of CO2/H2 with Clostridium aceticum in biofilm reactors.},
journal = {Bioresource technology},
volume = {291},
number = {},
pages = {121760},
doi = {10.1016/j.biortech.2019.121760},
pmid = {31352165},
issn = {1873-2976},
mesh = {Acetic Acid/metabolism ; *Biofilms ; *Bioreactors ; Carbon Dioxide/*metabolism ; Clostridium/*physiology ; Fermentation ; Hydrogen/*metabolism ; },
abstract = {A lab-scale stirred-tank bioreactor was reversibly retrofitted to a packed-bed and a trickle-bed biofilm reactor to study and compare the conversion of CO2/H2 with immobilised Clostridiumaceticum. The biofilm reactors were characterised and their functionality confirmed. Up to 8.6 g of C. aceticum were immobilised onto 300 g sintered ceramic carrier material, proving biofilm formation to be a robust means for cell retention of C. aceticum. Continuous CO2/H2-fermentation studies were performed with both biofilm reactor configurations as function of dilution rates, partial gas pressures and gas flow rates. The experiments showed that in the packed-bed biofilm reactor, the acetate space-time yield was independent of the dilution rate, because of low H2 gas-liquid mass transfer rates (≤17 mmol H2 L-1 h-1). The continuous operation of the trickle-bed biofilm reactor increased the gas-liquid mass transfer rates to up to 56 mmol H2 L-1 h-1. Consequently, the acetate space-time yield of up to 14 mmol acetate L-1 h-1 was improved 3-fold at hydrogen conversions of up to 96%.},
}
@article {pmid31351106,
year = {2019},
author = {Bautista-Hernández, LA and Gómez-Olivares, JL and Buentello-Volante, B and Dominguez-Lopez, A and Garfias, Y and Acosta-García, MC and Calvillo-Medina, RP and Bautista-de Lucio, VM},
title = {Negative interaction of Staphylococcus aureus on Fusarium falciforme growth ocular isolates in an in vitro mixed biofilm.},
journal = {Microbial pathogenesis},
volume = {135},
number = {},
pages = {103644},
doi = {10.1016/j.micpath.2019.103644},
pmid = {31351106},
issn = {1096-1208},
abstract = {The interactions between prokaryotes and eukaryotes are abundant in nature. These microorganisms also interact in the human body. Fungal-bacteria interactions are present in many diseases. In this study, we evaluated the microbial interaction of Fusarium falciforme and Staphylococcus aureus developing mixed biofilm in vitro. When both microorganisms grew up together the mixed biofilm biomass decreased than F. falciforme monobiofilm biomass. S. aureus was able to interact and form aggregates over the mycelium and conidia surface of F. falciforme. Our results suggest that S. aureus could bind to colloidal chitin. On another hand, the supernatants from S. aureus biofilm and S. aureus-F. falciforme presented an antifungal effect over F. falciforme biofilm formation. Finally we found that the pH had an inhibitory effect over fungal biofilm formation. We concluded that S. aureus can affect the F. falciforme growth negatively in mixed biofilm involving factors like pH, supernatants compounds, anchor to chitin, and bacterial viability.},
}
@article {pmid31350606,
year = {2019},
author = {Schopf, A and Delatolla, R and Kirkwood, KM},
title = {Partial nitritation at elevated loading rates: design curves and biofilm characteristics.},
journal = {Bioprocess and biosystems engineering},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00449-019-02177-8},
pmid = {31350606},
issn = {1615-7605},
support = {497995-2017//Natural Sciences and Engineering Research Council of Canada/ ; },
abstract = {There is a need to develop low operational intensity, cost-effective, and small-footprint systems to treat wastewater. Partial nitritation has been studied using a variety of control strategies, however, a gap in passive operation is evident. This research investigates the use of elevated loading rates as a strategy for achieving low operational intensity partial nitritation in a moving bed biofilm reactor (MBBR) system. The effects of loading rates on nitrification kinetics and biofilm characteristics were determined at elevated, steady dissolved oxygen concentrations between 5.5 and 7.0 mg O2/L and ambient temperatures between 19 and 21 °C. Four elevated loading rates (3, 4, 5 and 6.5 g NH4+-N/m2 days) were tested with a distinct shift in kinetics being observed towards nitritation at elevated loadings. Complete partial nitritation (100% nitrite production) was achieved at 6.5 g NH4+-N/m2 days, likely due to thick biofilm (572 µm) and elevated NH4+-N load, which resulted in suppression of nitrite oxidation.},
}
@article {pmid31349525,
year = {2019},
author = {Ismail, NA and Amin, KAM and Majid, FAA and Razali, MH},
title = {Gellan gum incorporating titanium dioxide nanoparticles biofilm as wound dressing: Physicochemical, mechanical, antibacterial properties and wound healing studies.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {103},
number = {},
pages = {109770},
doi = {10.1016/j.msec.2019.109770},
pmid = {31349525},
issn = {1873-0191},
abstract = {In this work, the potential of titanium dioxide nanoparticles incorporated gellan gum (GG + TiO2-NPs) biofilm as wound dressing material was investigated. The GG + TiO2-NPs biofilm was prepared via evaporative casting technique and was characterized using FTIR, XRD, and SEM to study their physiochemical properties. The mechanical properties, swelling and water vapor transmission rate (WVTR) of biofilm was determined to comply with an ideal wound dressing material. In vitro and in vivo wound healing studies was carried out to evaluate the performance of GG + TiO2-NPs biofilm. In vitro wound healing was studied on 3 T3 mouse fibroblast cells for cell viability, cell proliferation, and scratch assay. The acridine orange/propidium iodide (AO/PI) staining and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were used to evaluate the viability of cell and cell proliferation. Cell migration assay was analyzed using Essen BioScience IncuCyteTM Zoom system. In vivo wound healing via open excision wounds model on Sprague Dawley rat was studied within 14 days. The FT-IR spectra of GG + TiO2-NPs biofilm show main bands assigned to OH stretching, OH deformation, and TiO stretching modes. XRD pattern of GG + TiO2-NPs biofilm suggesting that TiO2-NPs was successfully incorporated in biofilm and well distributed on the surface as proved by SEM analysis. The GG + TiO2-NPs biofilm shows higher mechanical strength and swelling (3.76 ± 0.11 MPa and 1061 ± 6%) as compared to pure GG film (3.32 ± 0.08 Mpa and 902 ± 6%), respectively. GG + TiO2-NPs biofilm shows good antibacterial properties as 9 ± 0.25 mm and 11 ± 0.06 mm exhibition zone was observed against Staphylococcus aureus and Escherichia coli bacteria, respectively. While no exhibition zone was obtained for pure GG biofilm. GG + TiO2-NPs biofilm also demonstrated better cell-to-cell interaction properties, as it's promoted cell proliferation and cell migration to accelerate open excision wound healing on Sprague Dawley rat. The wound treated with GG + TiO2-NPs biofilm was healed within 14 days, on the other hand, the wound is still can be seen when it was treated with GG. However, GG and GG + TiO2-NPs biofilm show no cytotoxicity effects on mouse fibroblast cells.},
}
@article {pmid31349520,
year = {2019},
author = {Vögeling, H and Plenagl, N and Seitz, BS and Duse, L and Pinnapireddy, SR and Dayyoub, E and Jedelska, J and Brüßler, J and Bakowsky, U},
title = {Synergistic effects of ultrasound and photodynamic therapy leading to biofilm eradication on polyurethane catheter surfaces modified with hypericin nanoformulations.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {103},
number = {},
pages = {109749},
doi = {10.1016/j.msec.2019.109749},
pmid = {31349520},
issn = {1873-0191},
abstract = {Catheter related infections are causing one third of all blood stream infections. The mortality of those infections is very high and the gold standard for catheter related blood stream infections (CR-BSI) is still the removal of the catheter and systemic antibiotic therapy. There already exist some approaches to prevent the biofilm formation on catheter material, which are far from ideal. A new strategy to prevent bacterial colonization on catheter surfaces is the application of photodynamic therapy (PDT). Therefor the surface has to be modified with substances that can be activated by light, leading to the production of cell toxic reactive oxygen species (ROS). Only small concentrations of the so called photosensitizer (PS) are necessary, avoiding side effects in human therapy. Furthermore, there is no resistance development in PDT. In this study polyurethane (PUR) surfaces were coated with hypericin nanoformulations, leading to 4.3 log10 reduction in bacterial growth in vitro. The effect could be enhanced by the application of ultrasound. The combination of PDT with ultrasound therapy led to a synergistic effect resulting in a 6.8 log10 reduction of viable counts. This minimal invasive method requires only an optical fibre inserted in the catheter lumen and an ultrasound device. Thus the implementation in daily clinical practice is very simple.},
}
@article {pmid31349502,
year = {2019},
author = {Torres-Rêgo, M and Gláucia-Silva, F and Rocha Soares, KS and de Souza, LBFC and Damasceno, IZ and Santos-Silva, ED and Lacerda, AF and Chaves, GM and Silva-Júnior, AAD and Fernandes-Pedrosa, MF},
title = {Biodegradable cross-linked chitosan nanoparticles improve anti-Candida and anti-biofilm activity of TistH, a peptide identified in the venom gland of the Tityus stigmurus scorpion.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {103},
number = {},
pages = {109830},
doi = {10.1016/j.msec.2019.109830},
pmid = {31349502},
issn = {1873-0191},
abstract = {Among several bioactive peptides identified from the venom glands of the Tityus stigmurus scorpion, one peptide with hypotensive action (TistH, Tityus stigmurus Hypotensin) showed multifunctional and biotechnological applications. The maximum efficacy of this class of compounds can be achieved by immobilizing it in specific and suitable biomaterials or suitable carriers. In this study, distinct entrapment methods of TistH in chitosan nanoparticles was tested using its incorporation (CN-TistH-Inc) or adsorption (CN-TistH-Ads) methods by ionotropic gelification. Physico-chemical properties as well as biocompatibility and antifungal efficacy were assessed for different samples. Atomic force microscopy and field emission gun scanning electronic microscopy images associated with particle size measurements demonstrated that the two methods induced cationic spherical, small (< 160 nm), and narrow-sized (PdI about 0.3) nanoparticles, even after peptide loading greater than 96.5%, which was confirmed using Fourier transform infrared spectroscopy. The colloidal suspensions showed to be stable for 8 weeks and were able to induce the desired slow in vitro peptide release. Cytotoxicity assays performed in normal cells originated from murine macrophages (RAW 264.7) and kidneys of African green monkeys (Vero E6) suggested biocompatibility of samples. The CN-TistH-Inc and CN-TistH-Ads showed a minimal inhibitory concentration of 89.2 μg.mL-1 against Candida albicans, 11.1 μg.mL-1 for C. parapsilosis and C. tropicalis, confirmed by minimum fungicidal concentrations assay. Moreover, the TistH-loaded cross-linked chitosan nanoparticles significantly reduced the biofilm formation of clinical yeast sepsis of C. tropicalis and C. krusei, as well as clinical yeasts of vulvovaginal candidiasis of C. albicans. In this approach, biodegradable nanocarriers prepared using simple and reproducible methods demonstrated the ability to deliver the TistH peptide from T. stigmurus and improve its antifungal efficacy.},
}
@article {pmid31349480,
year = {2019},
author = {Hasan, N and Cao, J and Lee, J and Naeem, M and Hlaing, SP and Kim, J and Jung, Y and Lee, BL and Yoo, JW},
title = {PEI/NONOates-doped PLGA nanoparticles for eradicating methicillin-resistant Staphylococcus aureus biofilm in diabetic wounds via binding to the biofilm matrix.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {103},
number = {},
pages = {109741},
doi = {10.1016/j.msec.2019.109741},
pmid = {31349480},
issn = {1873-0191},
abstract = {Wounds infected with methicillin-resistant Staphylococcus aureus (MRSA) biofilm represent a high risk in patients with diabetes. Nitric oxide (NO) has shown promise in dispersing biofilm and wound healing. For an effective treatment of MRSA biofilm-infected wounds, however, NO needs to be supplied to the biofilm matrix in a sustainable manner due to a short half-life and limited diffusion distance of NO. In this study, polyethylenimine/diazeniumdiolate (PEI/NONOate)-doped PLGA nanoparticles (PLGA-PEI/NO NPs) with an ability to bind to the biofilm matrix are developed to facilitate the NO delivery to MRSA biofilm-infected wound. In simulated wound fluid, PLGA-PEI/NO NPs show an extended NO release over 4 days. PLGA-PEI/NO NPs firmly bind to the MRSA biofilm matrix, resulting in a greatly enhanced anti-biofilm activity. Moreover, PLGA-PEI/NO NPs accelerate healing of MRSA biofilm-infected wounds in diabetic mice along with complete biofilm dispersal and reduced bacterial burden. These results suggest that the biofilm-binding NO-releasing NPs represent a promising NO delivery system for the treatments of biofilm-infected chronic wounds.},
}
@article {pmid31349180,
year = {2019},
author = {di Biase, A and Kowalski, MS and Devlin, TR and Oleszkiewicz, JA},
title = {Moving bed biofilm reactor technology in municipal wastewater treatment: A review.},
journal = {Journal of environmental management},
volume = {247},
number = {},
pages = {849-866},
doi = {10.1016/j.jenvman.2019.06.053},
pmid = {31349180},
issn = {1095-8630},
abstract = {The review encompasses the development of municipal wastewater treatment process using MBBR from early stages, established application, and recent advancements. An overview of main drivers leading to the MBBR technology development over its early stage is discussed. Biocarriers types and features together with biofilm development and role of extracellular polymeric substances (EPS) are presented, ultimately, addressing the challenge in decreasing startup time required for full operation. Furthermore, the review investigates the state of the art of MBBR technology for nutrient removal (i.e., COD and BOD, nitrogen and phosphorus) through process functionality and configuration of established (e.g., IFAS) and under development (e.g. PN/A) applications. Reactor operational characteristics such as filling fractions, mixing properties, dissolved oxygen requirements, and loading rates are presented and related to full scale examples. Current literature discussing the most recent studies on MBBR capability in reduction and removal of chemicals of emerging concern (CEC) released is presented. Ultimately, high rate carbon and nitrogen removal through A/B stage process are examined in its main operational parameters and its application towards energy neutrality suggesting novel MBBR application to further reduce energy requirements and plant footprint.},
}
@article {pmid31347191,
year = {2019},
author = {Kannan, S and Krishnamoorthy, G and Kulanthaiyesu, A and Marudhamuthu, M},
title = {Effect of biosurfactant derived from Vibrio natriegens MK3 against Vibrio harveyi biofilm and virulence.},
journal = {Journal of basic microbiology},
volume = {59},
number = {9},
pages = {936-949},
doi = {10.1002/jobm.201800706},
pmid = {31347191},
issn = {1521-4028},
support = {//Department of Biotechnology, Interdisciplinary Programme in Life Sciences/ ; //University Grants Commission (UGC-NFOBC)/ ; },
abstract = {Vibrio harveyi is a marine luminous pathogen, which causes biofilm-mediated infections, pressures the search for an innovative alternate approach to strive against vibriosis in aquaculture. This study anticipated to explore the effect of glycolipid biosurfactant as an antipathogenic against V. harveyi to control vibriosis. In this study, 27 bacterial strains were isolated from marine soil sediments. Out of these, 11 strains exhibited surfactant activity and the strain MK3 showed high emulsification index. The potent strain was identified as Vibrio natriegens and named as V. natriegens MK3. The extracted biosurfactant was purified using high-performance liquid chromatography and it was efficient to decrease the surface tension of the growth medium up to 21 mN/m. The functional group and composition of the biosurfactant were determined by Fourier-transform infrared spectroscopy and nuclear magnetic resonance spectroscopy spectral studies and the nature of the biosurfactant was identified as glycolipid. The surfactant was capable of reducing the biofilm formation, bioluminescence, extracellular polysaccharide synthesis, and quorum sensing in marine shrimp pathogen V. harveyi. The antagonistic effect of biosurfactant was evaluated against V. harveyi-infected brine shrimp Artemia salina. This study reveals that biosurfactant can be considered for the management of biofilm-related aquatic infections.},
}
@article {pmid31346374,
year = {2019},
author = {Listiana-Kriswandini, I and Budi-Rahardjo, M and Soesilawati, P and Prisca-Suciadi, A},
title = {Detection of Candida albicans biofilm proteins induced by glucose, lactose, soy protein, and iron.},
journal = {Journal of clinical and experimental dentistry},
volume = {11},
number = {6},
pages = {e542-e546},
doi = {10.4317/jced.55787},
pmid = {31346374},
issn = {1989-5488},
abstract = {Background: Oral candidiasis is one of the most common fungal infections, which attack the mucosa of the oral cavity. These lesions are mostly caused by the fungal species Candida albicans. Candida albicans is included in the normal oral microorganisms that are opportunistic pathogens, and its presence is quite large, which can reach 75% of the total oral fungal population. Research on specific proteins of Candida biofilm can be an alternative to early prevention of oral infections such as Oral Candidiasis. This biofilm protein can be used as a reference in making kits to detect the presence of microbes that cause infectious diseases. The purpose of this study was to determine molecular weight of Candida albicans biofilm protein induced by 5% glucose, 5% lactose, soy protein, and 5% iron.<br><br>Material and Methods: This experimental laboratory study used SDS-PAGE electrophoresis to determine the molecular weight of Candida albicans biofilm proteins induced by glucose 5%, lactose 5%, soy protein, and iron 5%.<br><br>Results: Biofilm induced by 5% glucose shows four protein bands: 71,6 kDa; 56,1 kDa; 49,7 kDa; and 41 kDa. Biofilm induced by 5% lactose shows seven protein bands: 71 kDa; 61,2 kDa; 57,7 kDa; 55,3 kDa; 48,9 kDa; 39,5 kDa; and 29,8 kDa. Biofilm induced by soy protein shows one protein band: 49,4 kDa. Biofilm induced by 5% iron shows one protein band: 51,1 kDa.<br><br>Conclusions: Candida albicans biofilm induced by 5% glucose has four protein band candidates, 5% lactose has seven candidates of protein band, and soy protein and 5% iron each has a candidate of protein band, which can be used as a target for the detection of oral Candidiasis. Key words:Biofilm protein, Candida albicans, molecular weight, oral candidiasis.},
}
@article {pmid31345229,
year = {2019},
author = {Besser, M and Terberger, J and Weber, L and Ghebremedhin, B and Naumova, EA and Arnold, WH and Stuermer, EK},
title = {Impact of probiotics on pathogen survival in an innovative human plasma biofilm model (hpBIOM).},
journal = {Journal of translational medicine},
volume = {17},
number = {1},
pages = {243},
doi = {10.1186/s12967-019-1990-4},
pmid = {31345229},
issn = {1479-5876},
support = {IFF2018-61//University of Witten/Herdecke/ ; },
abstract = {BACKGROUND: Despite of medical advances, the number of patients suffering on non-healing chronic wounds is still increasing. This fact is attended by physical and emotional distress and an economic load. The majority of chronic wounds are infected of harmful microbials in a protecting extracellular matrix. These biofilms inhibit wound healing. Biofilm-growing bacteria developed unique survival properties, which still challenge the appropriate wound therapy. The present in-vitro biofilm models are not suitable for translational research. By means of a novel in-vivo like human plasma biofilm model (hpBIOM), this study systematically analysed the influence of 3 probiotics on the survival of five clinically relevant pathogenic microorganisms.<br><br>METHODS: Human plasma was used to produce the innovate biofilm. Pathogenic microorganisms were administered to the plasma. By stimulating the production of a fibrin scaffold, stable coagula-like discs with integrated pathogens were produced. The five clinically relevant pathogens P. aeruginosa, S. aureus, S. epidermidis, E. faecium and C. albicans were challenged to the probiotics L. plantarum, B. lactis and S. cerevisiae. The probiotics were administered on top of the biofilm and the survival was quantified after 4 h and 24 h of incubation. For statistics, two-way ANOVA with post-hoc Tukey's HSD test was applied. P-value > 0.05 was considered to be significant.<br><br>RESULTS: SEM micrographs depicted the pathogens on the surface of the fibrin scaffold, arranged in close proximity and produced the glycocalyx. The application of probiotics induced different growth-reducing capacities towards the pathogens. B. lactis and S. cerevisiae showed slight bacteria-reducing properties. The survival of C. albicans was not affected at all. The most antimicrobial activity was detected after the treatment with L. plantarum.<br><br>CONCLUSIONS: This study successfully reproduced a novel human biofilm model, which provides a human wound milieu and individual immune competence. The success of bacteriotherapy is dependent on the strain combination, the number of probiotics and the activity of the immune cells. The eradicating effect of L. plantarum on P. aeruginosa should be emphasized.},
}
@article {pmid31344909,
year = {2019},
author = {Zhang, T and Ying, D and Qi, M and Li, X and Fu, L and Sun, X and Wang, L and Zhou, Y},
title = {Anti-Biofilm Property of Bioactive Upconversion Nanocomposites Containing Chlorin e6 against Periodontal Pathogens.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {15},
pages = {},
doi = {10.3390/molecules24152692},
pmid = {31344909},
issn = {1420-3049},
support = {81570983//National Natural Science Foundation of China/ ; 20180414030GH//International Cooperation Project of Science and Technology Development Jilin Province/ ; },
abstract = {Photodynamic therapy (PDT) based periodontal disease treatment has received extensive attention. However, the deep tissue location of periodontal plaque makes the conventional PDT encounter a bottleneck. Herein, upconversion fluorescent nanomaterial with near-infrared light excitation was introduced into the treatment of periodontal disease, overcoming the limited tissue penetration depth of visible light in PDT. Photosensitizer Ce6 molecules were combined with upconversion nanoparticles (UCNPs) NaYF4:Yb,Er with a novel strategy. The hydrophobic UCNPs were modified with amphiphilic silane, utilizing the hydrophobic chain of the silane to bind to the hydrophobic groups of the UCNPs through a hydrophobic-hydrophobic interaction, and the Ce6 molecules were loaded in this hydrophobic layer. This achieves both the conversion of the hydrophobic to the hydrophilic surface and the loading of the oily photosensitizer molecules. Because the excitation position of the Ce6 molecule is in the red region, Mn ions were doped to enhance red light, and thus the improved PDT function. This Ce6 loaded UCNPs composites with efficient red upconversion luminescence show remarkable bacteriological therapeutic effect on Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum and the corresponding biofilms under 980 nm irradiation, indicating a high application prospect in the treatment of periodontal diseases.},
}
@article {pmid31344638,
year = {2019},
author = {Jensen, MB and Strübing, D and de Jonge, N and Nielsen, JL and Ottosen, LDM and Koch, K and Kofoed, MVW},
title = {Stick or leave - Pushing methanogens to biofilm formation for ex situ biomethanation.},
journal = {Bioresource technology},
volume = {291},
number = {},
pages = {121784},
doi = {10.1016/j.biortech.2019.121784},
pmid = {31344638},
issn = {1873-2976},
mesh = {*Biofilms ; Biomass ; Bioreactors ; Euryarchaeota/*physiology ; Methane/*metabolism ; Plankton/metabolism ; },
abstract = {Biomethanation exploits the ability of methanogenic archaea to convert CO2 and renewable H2 from electrolysis to biomethane. Biofilm reactors are promising for biomethanation scale-up due to high CH4 productivity and low energy input for H2 gas-liquid mass transfer. Effects of operational conditions on biofilm dynamics remain largely uncharacterized but may increase reactor potentials further. This study investigated the effect of hydraulic retention time (HRT) on methanogenic biofilm activity and composition. Commercial carriers floating in liquid were exposed to H2/CO2 for 87 days with the liquid phase being subject to either 18 hours, 10 days, or 20 days HRT. Methanogenic biofilms were dominated by hydrogenotrophic methanogens, but biofilm CH4 productivity was enhanced at 18 hours HRT due to wash-out of competing planktonic species, which otherwise hampered proliferation of biofilm biomass at long HRT. It is suggested that high-rate biofilm reactors can increase methanogenic biofilm activity by minimizing the liquid's H2 exposure.},
}
@article {pmid31344634,
year = {2019},
author = {Song, T and Li, S and Jin, J and Yin, Z and Lu, Y and Bao, M and Li, Y},
title = {Enhanced hydrolyzed polyacrylamide removal from water by an aerobic biofilm reactor-ozone reactor-aerobic biofilm reactor hybrid treatment system: Performance, key enzymes and functional microorganisms.},
journal = {Bioresource technology},
volume = {291},
number = {},
pages = {121811},
doi = {10.1016/j.biortech.2019.121811},
pmid = {31344634},
issn = {1873-2976},
abstract = {Degradation of hydrolyzed polyacrylamide-containing (HPAM-containing) wastewater was investigated in a lab-scale aerobic-ozonic-aerobic hybrid treatment system. When the HPAM concentration was 500 mg L-1 and the ozone dose was 25 g O3/g TOC, the HPAM removal rate reached 90.79%. Experimental results obtained from gel permeation chromatography (GPC) and rheometer indicated that the refractory HPAM was decomposed into small-molecule compounds. High performance liquid chromatography (HPLC) analysis showed that there was no acrylamide (AM) in the effluent of the system. Microbial communities in two aerobic biofilm reactors (ABRs) were analyzed by Illumina MiSeq Sequencing, which indicated that norank_f_Cytophagaceae, Meiothermus, Bacillus, etc. were keystone functional bacterial genera and Methanobacterium, norank_p_Bathyarchaeota, norank_c_Marine_Group_Ⅰ, etc. were dominant functional archaeal groups. To our knowledge, this is the first study to treat HPAM-containing wastewater using an aerobic-ozonic-aerobic hybrid process. Good removal efficiencies and presence of functional microorganisms demonstrated that the hybrid treatment system was practical for treating HPAM-containing wastewater.},
}
@article {pmid31342619,
year = {2019},
author = {Sivadon, P and Barnier, C and Urios, L and Grimaud, R},
title = {Biofilm formation as a microbial strategy to assimilate particulate substrates.},
journal = {Environmental microbiology reports},
volume = {},
number = {},
pages = {},
doi = {10.1111/1758-2229.12785},
pmid = {31342619},
issn = {1758-2229},
support = {BIOLEO//Conseil Général des Pyrénées Atlantiques/ ; },
abstract = {In most ecosystems, a large part of the organic carbon is not solubilized in the water phase. Rather, it occurs as particles made of aggregated hydrophobic and/or polymeric natural or man-made organic compounds. These particulate substrates are degraded by extracellular digestion/solubilization implemented by heterotrophic bacteria that form biofilms on them. Organic particle-degrading biofilms are widespread and have been observed in aquatic and terrestrial natural ecosystems, in polluted and man-driven environments and in the digestive tracts of animals. They have central ecological functions as they are major players in carbon recycling and pollution removal. The aim of this review is to highlight bacterial adhesion and biofilm formation as central mechanisms to exploit the nutritive potential of organic particles. It focuses on the mechanisms that allow access and assimilation of non-dissolved organic carbon, and considers the advantage provided by biofilms for gaining a net benefit from feeding on particulate substrates. Cooperative and competitive interactions taking place in biofilms feeding on particulate substrates are also discussed.},
}
@article {pmid31341834,
year = {2019},
author = {Gawish, S and Abbass, A and Abaza, A},
title = {Occurrence and biofilm forming ability of Pseudomonas aeruginosa in the water output of dental unit waterlines in a dental center in Alexandria, Egypt.},
journal = {Germs},
volume = {9},
number = {2},
pages = {71-80},
doi = {10.18683/germs.2019.1160},
pmid = {31341834},
issn = {2248-2997},
abstract = {Introduction: Dental unit waterlines (DUWLs) are notorious for being contaminated with different bacterial species including the opportunistic pathogen Pseudomonas aeruginosa which poses a risk to patients and professionals. This work aimed at studying the occurrence and biofilm-forming ability (BFA) of P. aeruginosa in the output of DUWLs in a dental center in Egypt.<br><br>Methods: Water samples were collected from the outlets of the high-speed hand piece, the air/water syringe and the cup filler waterlines. Bacteriological analysis included heterotrophic plate count (HPC), isolation and identification of P. aeruginosa and determination of the antimicrobial susceptibility and the BFA of the isolates by tissue culture plate (TCP) method and tube method (TM).<br><br>Results: The average concentration of HPC bacteria in the output of the 3 DUWLs was 2.9×104 CFU/μL where 88.3% of the samples exceeded the Egyptian standards for drinking water (<50 CFU L). P. aeruginosa was isolated from nine cup filler samples (which had a water source different from the other waterlines). The isolates were sensitive to all tested antimicrobials. Of these nine isolates, 6, 5 and 4 were positive for BFA by TCP, modified TCP and TM, respectively.<br><br>Conclusions: More stringent measures are required to ensure safer dental water; as the majority of studied samples exceeded the required HPC bacterial limit and P. aeruginosa isolates were detected. P. aeruginosa isolates from DUWLs may not be as resistant to antibiotics as what is reported in the literature about clinical isolates. Some P. aeruginosa isolates can colonize DUWLs despite their inability to form biofilms in experimental testing.},
}
@article {pmid31341833,
year = {2019},
author = {Ahmed, DM and Messih, MAWA and Ibrahim, NH and Meabed, MH and Abdel-Salam, SM},
title = {Frequency of icaA and icaD determinants and biofilm formation among coagulase-negative staphylococci associated with nasal carriage in neonatal intensive care units.},
journal = {Germs},
volume = {9},
number = {2},
pages = {61-70},
doi = {10.18683/germs.2019.1159},
pmid = {31341833},
issn = {2248-2997},
abstract = {Introduction: Nasal colonization with coagulase-negative staphylococci (CoNS) may be a preliminary risk factor for systemic infection. The aim of this study was to assess the frequency of ica A and D genes and biofilm formation among hospital-acquired nasal colonizing CoNS strains isolated from neonates in the neonatal intensive care units (NICUs). Antibiotic sensitivity patterns and some relevant risk factors were estimated.<br><br>Methods: This study assessed nasal colonization with CoNS among neonates at days one and three of admission to NICUs of Beni-Suef University Hospital and Beni-Suef General Hospital from November 2015 to May 2016. The isolates were screened and identified; susceptibility testing was performed. Biofilm formation was examined using the Congo red agar method. Isolates identified as CoNS were tested by polymerase chain reaction (PCR) for the presence of mecA and icaA and icaD genes.<br><br>Results: A total of 340 nasal swabs were collected from 170 neonates. The incidence of nasal colonization with CoNS was 50%. The species most frequently isolated were S. haemolyticus and S. epidermidis. Multidrug resistance (MDR) was detected in 86% of isolates. It was found that there was a strong association between the presence of mecA gene and phenotypic resistance to methicillin and also the presence of the icaA gene and biofilm formation.<br><br>Conclusions: Neonates admitted to NICUs can become reservoirs for CoNS strains, leading to potential dissemination of MDR strains into the community.},
}
@article {pmid31340580,
year = {2019},
author = {Bessa, LJ and Manickchand, JR and Eaton, P and Leite, JRSA and Brand, GD and Gameiro, P},
title = {Intragenic Antimicrobial Peptide Hs02 Hampers the Proliferation of Single- and Dual-Species Biofilms of P. aeruginosa and S. aureus: A Promising Agent for Mitigation of Biofilm-Associated Infections.},
journal = {International journal of molecular sciences},
volume = {20},
number = {14},
pages = {},
doi = {10.3390/ijms20143604},
pmid = {31340580},
issn = {1422-0067},
support = {UID/QUI/50006/2019//FCT/MCTES through national funds/ ; 0193.000866/2015//FAP-DF/ ; },
abstract = {Pseudomonas aeruginosa and Staphylococcus aureus are two major pathogens involved in a large variety of infections. Their co-occurrence in the same site of infection has been frequently reported and is linked to enhanced virulence and difficulty of treatment. Herein, the antimicrobial and antibiofilm activities of an intragenic antimicrobial peptide (IAP), named Hs02, which was uncovered from the human unconventional myosin 1H protein, were investigated against several P. aeruginosa and S. aureus strains, including multidrug-resistant (MDR) isolates. The antibiofilm activity was evaluated on single- and dual-species biofilms of P. aeruginosa and S. aureus. Moreover, the effect of peptide Hs02 on the membrane fluidity of the strains was assessed through Laurdan generalized polarization (GP). Minimum inhibitory concentration (MIC) values of peptide Hs02 ranged from 2 to 16 μg/mL against all strains and MDR isolates. Though Hs02 was not able to hamper biofilm formation by some strains at sub-MIC values, it clearly affected 24 h preformed biofilms, especially by reducing the viability of the bacterial cells within the single- and dual-species biofilms, as shown by confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM) images. Laurdan GP values showed that Hs02 induces membrane rigidification in both P. aeruginosa and S. aureus. Peptide Hs02 can potentially be a lead for further improvement as an antibiofilm agent.},
}
@article {pmid31340472,
year = {2019},
author = {Al-Bakri, AG and Mahmoud, NN},
title = {Photothermal-Induced Antibacterial Activity of Gold Nanorods Loaded into Polymeric Hydrogel against Pseudomonas aeruginosa Biofilm.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {14},
pages = {},
doi = {10.3390/molecules24142661},
pmid = {31340472},
issn = {1420-3049},
support = {1820-1104//the Deanship of Scientific Research at The University of Jordan/ ; 2017-2016/64/04//Deanship of Scientific Research and Graduate Studies at Al-Zaytoonah University of Jordan/ ; 3/2017//Abdul Hameed Shoman Foundation, Amman, Jordan/ ; },
abstract = {In this study, the photothermal-induced bactericidal activity of phospholipid-decorated gold nanorods (DSPE-AuNR) suspension against Pseudomonas aeruginosa planktonic and biofilm cultures was investigated. We found that the treatment of planktonic culture of Pseudomonas aeruginosa with DSPE-AuNR suspension (0.25-0.03 nM) followed by a continuous laser beam exposure resulted in ~6 log cycle reduction of the bacterial viable count in comparison to the control. The percentage reduction of Pseudomonas aeruginosa biofilm viable count was ~2.5-6.0 log cycle upon laser excitation with different concentrations of DSPE-AuNR as compared to the control. The photothermal ablation activity of DSPE-AuNR (0.125 nM) loaded into poloxamer 407 hydrogel against Pseudomonas aeruginosa biofilm resulted in ~4.5-5 log cycle reduction in the biofilm viable count compared to the control. Moreover, transmission electron microscope (TEM) images of the photothermally-treated bacteria revealed a significant change in the bacterial shape and lysis of the bacterial cell membrane in comparison to the untreated bacteria. Furthermore, the results revealed that continuous and pulse laser beam modes effected a comparable photothermal-induced bactericidal activity. Therefore, it can be concluded that phospholipid-coated gold nanorods present a promising nanoplatform to eradicate Pseudomonas aeruginosa biofilm responsible for common skin diseases.},
}
@article {pmid31338728,
year = {2019},
author = {Zaatout, N and Ayachi, A and Kecha, M},
title = {Epidemiological investigation of subclinical bovine mastitis in Algeria and molecular characterization of biofilm-forming Staphylococcus aureus.},
journal = {Tropical animal health and production},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11250-019-02015-9},
pmid = {31338728},
issn = {1573-7438},
abstract = {Thirty dairy farms were selected for this study; the first objective of our study was to investigate the prevalence of subclinical bovine mastitis (SCM) in Eastern Algeria, from 600 lactating cows, and to identify potential risk factors associated with the occurrence of bovine mastitis and bacteria isolation using logistic regression. The second objective was to evaluate biofilm formation capacity and detect biofilm-associated genes of S. aureus, isolated from SCM cases. Molecular typing was investigated by spa typing. The prevalence of mastitis at cow and quarter level was 37.66% (226/600) and 27.17% (555/2042), respectively. Stage of lactation, cow breed, milk production, and the study area were factors associated with SCM. In addition, the most frequent pathogens isolated from mastitic milk were coagulase-negative staphylococci (CNS), E. coli, and S. aureus. The study area was highly associated with SCM caused by S. aureus; cows from Setif province were 18 times more affected with SCM caused by S. aureus compared to cows from Batna province (OR = 18.6, 95%CI 2.038-171.2), but were less affected with SCM caused by CNS isolates (OR = 0.17, 95%CI 0.033-0.868). Moreover, cows with milk production less than 10 L per day increased (p < 0.05) the prevalence of mastitis caused by E. coli. All the S. aureus isolates had biofilm-forming ability, and 41.66% of isolates were positive for adhesion genes (icaA, icaD, fbnA, and clfA). This study, therefore, warrants the need for improving sanitary measures and strict hygienic measures, and presents the first insight into biofilm-forming ability of S. aureus strains causing mastitis in dairy herds in Algeria, which will help in tracking the evolution of epidemic strains responsible for causing bovine mastitis.},
}
@article {pmid31338076,
year = {2019},
author = {Alviz-Gazitua, P and Fuentes-Alburquenque, S and Rojas, LA and Turner, RJ and Guiliani, N and Seeger, M},
title = {The Response of Cupriavidus metallidurans CH34 to Cadmium Involves Inhibition of the Initiation of Biofilm Formation, Decrease in Intracellular c-di-GMP Levels, and a Novel Metal Regulated Phosphodiesterase.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1499},
doi = {10.3389/fmicb.2019.01499},
pmid = {31338076},
issn = {1664-302X},
abstract = {Cadmium is a highly toxic heavy metal for biological systems. Cupriavidus metallidurans CH34 is a model strain to study heavy metal resistance and bioremediation as it is able to deal with high heavy metal concentrations. Biofilm formation by bacteria is mediated by the second messenger bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP). The aim of this study was to characterize the response of C. metallidurans CH34 planktonic and biofilm cells to cadmium including their c-di-GMP regulatory pathway. Inhibition of the initiation of biofilm formation and EPS production by C. metallidurans CH34 correlates with increased concentration of cadmium. Planktonic and biofilm cells showed similar tolerance to cadmium. During exposure to cadmium an acute decrease of c-di-GMP levels in planktonic and biofilm cells was observed. Transcription analysis by RT-qPCR showed that cadmium exposure to planktonic and biofilm cells induced the expression of the urf2 gene and the mercuric reductase encoding merA gene, which belong to the Tn501/Tn21 mer operon. After exposure to cadmium, the cadA gene involved in cadmium resistance was equally upregulated in both lifestyles. Bioinformatic analysis and complementation assays indicated that the protein encoded by the urf2 gene is a functional phosphodiesterase (PDE) involved in the c-di-GMP metabolism. We propose to rename the urf2 gene as mrp gene for metal regulated PDE. An increase of the second messenger c-di-GMP content by the heterologous expression of the constitutively active diguanylate cyclase PleD correlated with an increase in biofilm formation and cadmium susceptibility. These results indicate that the response to cadmium in C. metallidurans CH34 inhibits the initiation of biofilm lifestyle and involves a decrease in c-di-GMP levels and a novel metal regulated PDE.},
}
@article {pmid31336660,
year = {2019},
author = {Cadena, M and Kelman, T and Marco, ML and Pitesky, M},
title = {Understanding Antimicrobial Resistance (AMR) Profiles of Salmonella Biofilm and Planktonic Bacteria Challenged with Disinfectants Commonly Used During Poultry Processing.},
journal = {Foods (Basel, Switzerland)},
volume = {8},
number = {7},
pages = {},
doi = {10.3390/foods8070275},
pmid = {31336660},
issn = {2304-8158},
abstract = {Foodborne pathogens such as Salmonella that survive cleaning and disinfection during poultry processing are a public health concern because pathogens that survive disinfectants have greater potential to exhibit resistance to antibiotics and disinfectants after their initial disinfectant challenge. While the mechanisms conferring antimicrobial resistance (AMR) after exposure to disinfectants is complex, understanding the effects of disinfectants on Salmonella in both their planktonic and biofilm states is becoming increasingly important, as AMR and disinfectant tolerant bacteria are becoming more prevalent in the food chain. This review examines the modes of action of various types of disinfectants commonly used during poultry processing (quaternary ammonium, organic acids, chlorine, alkaline detergents) and the mechanisms that may confer tolerance to disinfectants and cross-protection to antibiotics. The goal of this review article is to characterize the AMR profiles of Salmonella in both their planktonic and biofilm state that have been challenged with hexadecylpyridinium chloride (HDP), peracetic acid (PAA), sodium hypochlorite (SHY) and trisodium phosphate (TSP) in order to understand the risk of these disinfectants inducing AMR in surviving bacteria that may enter the food chain.},
}
@article {pmid31336253,
year = {2019},
author = {Tian, Z and Liu, R and Zhang, H and Yang, M and Zhang, Y},
title = {Developmental dynamics of antibiotic resistome in aerobic biofilm microbiota treating wastewater under stepwise increasing tigecycline concentrations.},
journal = {Environment international},
volume = {131},
number = {},
pages = {105008},
doi = {10.1016/j.envint.2019.105008},
pmid = {31336253},
issn = {1873-6750},
abstract = {This study aimed to investigate the impact of tigecycline, the third generation tetracycline, on the antibiotic resistance development in environmental microbiota. Two biological contact oxidation reactors containing aerobic biofilm microbiota were constructed, one of which was constantly fed with synthetic wastewater spiked with increasing concentrations of tigecycline (0 to 25 mg/L) under a hydrolytic retention time of 24 h. Over a period of 636 days, chemical oxygen demand removal over 90% and complete nitrification were achieved for both the control and tigecycline-exposed reactors, and effluent tigecycline concentrations in the tigecycline-exposed system were always <0.051 mg/L. Significant increases (p < 0.01) in resistome abundance and resistant bacteria ratio were detected at a tigecycline dose of 10 and 25 mg/L, respectively, revealed by metagenomic sequencing and culture-based method. The increase of resistome in the tigecycline system was mainly attributed to the enrichment of tetX, one cooperative tetracycline degrading gene. Partial canonical correspondence analysis showed that the change of resistome was mainly driven by bacterial community shift (vertical pathway). Network and genome binning analyses further suggested that the proliferation of Flavobacterium harboring tetX contributed to a relatively low community-wide resistance development in the aerobic biofilm microbiota under tigecycline selection by reducing the antibiotic concentration. This work provides scientific bases for the management and evaluation of the resistance risk induced by this novel antibiotic.},
}
@article {pmid31336203,
year = {2019},
author = {Chávez-Andrade, GM and Tanomaru-Filho, M and Basso Bernardi, MI and de Toledo Leonardo, R and Faria, G and Guerreiro-Tanomaru, JM},
title = {Antimicrobial and biofilm anti-adhesion activities of silver nanoparticles and farnesol against endodontic microorganisms for possible application in root canal treatment.},
journal = {Archives of oral biology},
volume = {107},
number = {},
pages = {104481},
doi = {10.1016/j.archoralbio.2019.104481},
pmid = {31336203},
issn = {1879-1506},
abstract = {OBJECTIVE: This study aimed to evaluate the antimicrobial and biofilm anti-adhesion activities of poly(vinyl alcohol)-coated silver nanoparticles (AgNPs-PVA) and farnesol against Enterococcus faecalis, Candida albicans or Pseudomonas aeruginosa.<br><br>DESIGN: Minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) of the solutions, as well as the effect on the biofilm biomass were evaluated. The biofilm anti-adhesion activity was evaluated using bovine root dentine treated with the solutions after 3 min of contact and analyzed by scanning electron microscopy (SEM) and by colony-forming units per milliliter (CFU mL-1) counting. Data were analyzed using ANOVA and Tukey's, the paired Student's t-test or Kruskal-Wallis and Dunn's tests (α = 0.05).<br><br>RESULTS: The MIC and MMC values (MIC/MMC) of the AgNPs-PVA and farnesol against E. faecalis were 42.5/50 μM and 0.85/1.0%, respectively. For C. albicans, the values were 27.5/37.5 μM and 1.75/2.5%; and for P. aeruginosa, 32.5/32.5 μM and 2.5/2.75%, respectively. Both solutions showed reduced biofilm biomass (p < 0.05). SEM analysis showed that dentine blocks treated with both solutions had lower biofilm formation than the control (saline), except for C. albicans. In the CFU mL-1 counting, biofilm cells were viable in the all groups in comparison with control (p > 0.05).<br><br>CONCLUSIONS: AgNPs-PVA and farnesol showed antimicrobial and biofilm anti-adhesion activities, as well as potential for use as coadjuvant in endodontic treatment, and may be an option as auxiliary procedure for root canal disinfection or to inhibit biofilm formation.},
}
@article {pmid31335442,
year = {2019},
author = {Munro, APS and Highmore, CJ and Webb, JS and Faust, SN},
title = {Diagnosis and treatment of biofilm infections in children.},
journal = {Current opinion in infectious diseases},
volume = {32},
number = {5},
pages = {505-509},
doi = {10.1097/QCO.0000000000000582},
pmid = {31335442},
issn = {1473-6527},
abstract = {PURPOSE OF REVIEW: Biofilm-associated infections cause difficulties in the management of childhood chronic infections and other diseases, due to the invasive nature of interventions which are often necessary for definitive management. Despite their importance, there are challenges in diagnosing biofilm infections and gaps in clinicians' understanding regarding the significance of biofilms.<br><br>RECENT FINDINGS: Many chronic infections associated with biofilms remain difficult or impossible to eradicate with conventional therapy. Surgical intervention, implant removal or long-term intermittent or suppressive antimicrobial therapy may be required. There are still significant challenges in detecting biofilms which presents a barrier in clinical practice and research. Novel therapies to disrupt biofilms are currently under investigation, which may help reduce the impact of antimicrobial resistance.<br><br>SUMMARY: Biofilm-associated infection should be considered wherever there is clinical concern for an infection affecting prosthetic material, where there is a predisposing condition such as suppurative lung disease; or in the setting of chronic or relapsing infections which may be culture negative. New diagnostic methods for detecting biofilms are a research priority for both clinical diagnosis and the ability to conduct high quality clinical trials of novel antibiofilm interventions.},
}
@article {pmid31335187,
year = {2019},
author = {Devivilla, S and Lekshmi, M and Kumar, SH and Valappil, RK and Roy, SD and Nayak, BB},
title = {Effect of Sodium Hypochlorite on Biofilm-Forming Ability of Histamine-Producing Bacteria Isolated from Fish.},
journal = {Journal of food protection},
volume = {82},
number = {8},
pages = {1417-1422},
doi = {10.4315/0362-028X.JFP-19-101},
pmid = {31335187},
issn = {1944-9097},
abstract = {Histamine poisoning occurs when temperature-abused marine fish containing elevated levels of histamine are consumed. Histamine-producing bacteria found in fish can colonize processing surfaces and form biofilms. In this study, the biofilm-forming abilities of histamine-producing bacteria from Indian mackerel (Rastrelliger kanagurta) and the effect of hypochlorite treatment on biofilm formation were studied. The isolates of this study produced histamine in the range of 471 to 2,126 ppm. The histidine decarboxylase gene hdc was detected in all isolates producing histamine except in one strain each of Psychrobacter pulmonis and Proteus vulgaris. All isolates tested in this study produced moderate biofilms under control conditions, whereas exposure to 1 and 3 ppm of sodium hypochlorite significantly enhanced biofilm formation. However, exposure to 5 ppm of sodium hypochlorite showed an inhibitory effect on biofilm formation by all the isolates except Klebsiella variicola. The results of this study suggest that histamine-producing bacteria can form stable biofilms and that this activity may be enhanced by the application of low levels of sodium hypochlorite, a phenomenon that might influence the persistence of histamine-producing bacteria in fish processing areas.},
}
@article {pmid31332872,
year = {2019},
author = {Wang, Y and Du, Z and Liu, Y and Wang, H and Xu, F and Liu, B and Zheng, Z},
title = {The nitrogen removal and sludge reduction performance of a multi-stage anoxic/oxic (A/O) biofilm reactor.},
journal = {Water environment research : a research publication of the Water Environment Federation},
volume = {},
number = {},
pages = {},
doi = {10.1002/wer.1188},
pmid = {31332872},
issn = {1554-7531},
support = {ZR2016EEM32//Natural Science Foundation of Shandong Province/ ; 2015GSF117003//Shandong Province Key Development Projects/ ; SFSJKY2018-01//Scientific and Technological Innovation Project of Planning and Design Institute of Huaihe River Basin Water Conservancy Administration Bureau of Shandong Province in 2018/ ; 51878394//National Natural Science Foundation/ ; UDC2017031612//Science and Technology Plans of Ministry of Housing and Urban-Rural Development of the People's Republic of China, and Opening Projects of Beijing Advanced Innovation Center for Future Urban Design, Beijing University of Civil Engineering and Architecture/ ; },
abstract = {To overcome the problems of high excess sludge yield and poor nitrogen removal efficiency in traditional biological treatment processes, a multi-stage A/O biofilm reactor was developed by combining the multi-stage A/O process with novel floating spherical carriers, resulting in repeated coupling of anoxic and aerobic environments. Results showed that the system achieved COD, NH 4 + - N , and TN removal efficiencies of 93.8%, 84.5%, and 75.7%, respectively, with average effluent concentrations lower than: 29.8 COD mg/L, 4.3 NH 4 + - N mg/L, and 13.2 TN mg/L. The observed sludge yield was 0.139 g MLSS/g COD, which was lower than that of the conventional activated sludge process. Microbial analysis showed that the community structure and cell morphology of microorganisms changed greatly with alternating aerobic-anoxic condition; high-throughput sequencing results proved that functional microorganisms can be enriched on the surface of the carries and therefore improved the nitrogen removal efficiency and meanwhile minimize the sludge yield within the system. PRACTITIONER POINTS: The research innovatively developed a novel floating spherical carrier and coupled it with multi-stage A/O process. The complex redox environments inside the floating spherical carriers improves the nitrogen removal efficiency and the sludge reduction effect. Nitrospirae, Hydrogenophaga promoted the nitrogen removal, Firmicutes, Bacteroidetes and Dechloromonas promoted the in-situ sludge reduction of the system.},
}
@article {pmid31331112,
year = {2019},
author = {Glasenapp, Y and Cattò, C and Villa, F and Saracchi, M and Cappitelli, F and Papenbrock, J},
title = {Promoting Beneficial and Inhibiting Undesirable Biofilm Formation with Mangrove Extracts.},
journal = {International journal of molecular sciences},
volume = {20},
number = {14},
pages = {},
doi = {10.3390/ijms20143549},
pmid = {31331112},
issn = {1422-0067},
support = {57265315//MIUR-DAAD Joint Mobility Program/ ; },
abstract = {The extracts of two mangrove species, Bruguieracylindrica and Lagunculariaracemosa, have been analyzed at sub-lethal concentrations for their potential to modulate biofilm cycles (i.e., adhesion, maturation, and detachment) on a bacterium, yeast, and filamentous fungus. Methanolic leaf extracts were also characterized, and MS/MS analysis has been used to identify the major compounds. In this study, we showed the following. (i) Adhesion was reduced up to 85.4% in all the models except for E. coli, where adhesion was promoted up to 5.10-fold. (ii) Both the sum and ratio of extracellular polysaccharides and proteins in mature biofilm were increased up to 2.5-fold and 2.6-fold in comparison to the negative control, respectively. Additionally, a shift toward a major production of exopolysaccharides was found coupled with a major production of both intracellular and extracellular reactive oxygen species. (iii) Lastly, detachment was generally promoted. In general, the L.racemosa extract had a higher bioactivity at lower concentrations than the B.cylindrica extract. Overall, our data showed a reduction in cells/conidia adhesion under B.cylindrica and L.racemosa exposure, followed by an increase of exopolysaccharides during biofilm maturation and a variable effect on biofilm dispersal. In conclusion, extracts either inhibited or enhanced biofilm development, and this effect depended on both the microbial taxon and biofilm formation step.},
}
@article {pmid31330991,
year = {2019},
author = {Vitale, M and Galluzzo, P and Buffa, PG and Carlino, E and Spezia, O and Alduina, R},
title = {Comparison of Antibiotic Resistance Profile and Biofilm Production of Staphylococcus aureus Isolates Derived from Human Specimens and Animal-Derived Samples.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {8},
number = {3},
pages = {},
doi = {10.3390/antibiotics8030097},
pmid = {31330991},
issn = {2079-6382},
support = {Fondo Finalizzato alla Ricerca//Università degli Studi di Palermo/ ; IZS SI 13/15 RC//Italian Ministry of Health/ ; IZS SI 08/16 RC//Italian Ministry of Health/ ; },
abstract = {BACKGROUND: The diffusion of antimicrobial resistance is a significant concern for public health worldwide. Staphylococcus aureus represents a paradigm microorganism for antibiotic resistance in that resistant strains appear within a decade after the introduction of new antibiotics.<br><br>METHODS: Fourteen S. aureus isolates from human specimens and twenty-one from samples of animal origin, were compared for their antimicrobial resistance and biofilm capability. In addition, they were characterized at the molecular level to detect the antimicrobial resistance mecA gene and genes related with enterotoxin, toxin, and biofilm production.<br><br>RESULTS: Both phenotypic and molecular analysis showed main differences among human- and animal-derived isolates. Among the human-derived isolates, more multidrug-resistant isolates were detected and mecA gene, enterotoxin, and toxin genes were more prevalent. Different genes involved in biofilm production were detected with bap present only in animal-derived isolates and sasC present in both isolates, however, with a higher prevalence in the human-derived isolates. Biofilm capability was higher in human-derived isolates mainly associated to the sasC gene.<br><br>CONCLUSIONS: The overall results indicate that human S. aureus isolates are more virulent and resistant than the isolates of animal origin randomly selected with no infection anamnesis. This study confirms that selection for more virulent and resistant S. aureus strains is related to the clinical practice.},
}
@article {pmid31330825,
year = {2019},
author = {Ly, S and Bajoul Kakahi, F and Mith, H and Phat, C and Fifani, B and Kenne, T and Fauconnier, ML and Delvigne, F},
title = {Engineering Synthetic Microbial Communities through a Selective Biofilm Cultivation Device for the Production of Fermented Beverages.},
journal = {Microorganisms},
volume = {7},
number = {7},
pages = {},
doi = {10.3390/microorganisms7070206},
pmid = {31330825},
issn = {2076-2607},
abstract = {Production of Cambodian rice wine involves complex microbial consortia. Indeed, previous studies focused on traditional microbial starters used for this product revealed that three microbial strains with complementary metabolic activities are required for an effective fermentation, i.e., filamentous fungi (Rhizopus oryzae), yeast (Saccharomycescerevisiae), and lactic acid bacteria (Lactobacillusplantarum). Modulating the ratio between these three key players led to significant differences, not only in terms of ethanol and organic acid production, but also on the profile of volatile compounds, in comparison with natural communities. However, we observed that using an equal ratio of spores/cells of the three microbial strains during inoculation led to flavor profile and ethanol yield close to that obtained through the use of natural communities. Compartmentalization of metabolic tasks through the use of a biofilm cultivation device allows further improvement of the whole fermentation process, notably by increasing the amount of key components of the aroma profile of the fermented beverage (i.e., mainly phenylethyl alcohol, isobutyl alcohol, isoamyl alcohol, and 2-methyl-butanol) and reducing the amount of off-flavor compounds. This study is a step forward in our understanding of interkingdom microbial interactions with strong application potential in food biotechnology.},
}
@article {pmid31330262,
year = {2019},
author = {Yu, M and Wang, X and Ling, F and Wang, H and Zhang, P and Shao, S},
title = {Atractylodes lancea volatile oils attenuated helicobacter pylori NCTC11637 growth and biofilm.},
journal = {Microbial pathogenesis},
volume = {135},
number = {},
pages = {103641},
doi = {10.1016/j.micpath.2019.103641},
pmid = {31330262},
issn = {1096-1208},
abstract = {Atractylodes lancea is a traditional Chinese perennial herb, which has been used for treating gastrointestinal diseases in traditional medicine. The aim of this study was to investigate the effect of Atractylodes lancea volatile oils on the planktonic growth and biofilm formation of Helicobacter pylori (H. pylori). Firstly, the minimal inhibitory concentration (MIC) of the volatile oils against H. pylori were determined using broth dilution method. SPSS17.0 was used to account 50% inhibiting concentration (IC50). Moreover, the anti-biofilm activity of the volatile oils was determined by crystal violet measurement and fluorescence microscope. Finally, gastric epithelial cells (GES-1 cells) were co-incubated with H. pylori with or without volatile oils treated. Real-time PCR and western blot were performed to detect the translocation of virulence factor Cag A. We found that Atractylodes lancea volatile oils inhibited the growth of H. pylori in a concentration dependent manner. The MIC and IC50 of volatile oils against H. pylori were 7.5 mg/mL and 2.181 mg/mL respectively. Fluorescence microscopy and crystal violet measurement indicated that volatile oils at sub-MIC concentration could reduce biofilm formation of H. pylori. In addition, volatile oils decreased the translocation of Cag A and reduced inflammatory cytokine IL-8 in GES-1 cells. Our results suggested that Atractylodes lancea volatile oils could be a potential compound of a novel class of H. pylori inhibitors with anti-H. pylori effects.},
}
@article {pmid31329599,
year = {2019},
author = {Lachica, MRCT and Anutrakunchai, C and Prajaneh, S and Nazmi, K and Bolscher, JGM and Taweechaisupapong, S},
title = {Synergistic effects of LFchimera and antibiotic against planktonic and biofilm form of Aggregatibacter actinomycetemcomitans.},
journal = {PloS one},
volume = {14},
number = {7},
pages = {e0217205},
doi = {10.1371/journal.pone.0217205},
pmid = {31329599},
issn = {1932-6203},
abstract = {Adjunctive use of antibiotics in periodontal treatment have limitations and disadvantages including bacterial resistance. Antimicrobial peptides (AMPs) are potential new agents that can combat bacterial infection. In this study, antimicrobial activity of different concentrations of conventional antibiotics minocycline (MH), doxycycline (DOX), and antimicrobial peptides LL-37, LL-31, Lactoferrin chimera (LFchimera) and Innate Defense Regulator Peptide 1018 (IDR-1018) against Aggregatibacter actinomycetemcomitans ATCC 43718 were determined using colony culturing assay. Subsequently, in vitro activity of the most effective drug and peptide combination was evaluated by checkerboard technique. Impact of the drug and peptide co-administration on biofilm at different stages, i.e., during adhesion and 1-day old biofilm was compared to each of the agents used alone. Results revealed that the killing effects of all AMPs range from 13-100%. In contrast, MH and DOX at 1 and 5 μM showed no killing activity and instead stimulated growth of bacteria. DOX has better killing activity than MH. LFchimera displayed the strongest killing amongst the peptides. Checkerboard technique revealed that combining DOX and LFchimera yielded synergism. Confocal laser scanning microscopy further showed that the combination of DOX and LFchimera caused significant reduction of bacterial adhesion and reduction of biomass, average biofilm thickness and substratum biofilm coverage of 1-day old biofilm compared to DOX and LFchimera alone. In conclusion, LFchimera alone and in combination with DOX exhibited strong antibacterial and anti-biofilm property against A. actinomycetemcomitans. The findings suggest that LFchimera should be considered for development as a new potential therapeutic agent that may be used as an adjunctive treatment for periodontitis.},
}
@article {pmid31329200,
year = {2019},
author = {Kwon, HY and Kim, JY and Liu, X and Lee, JY and Yam, JKH and Dahl Hultqvist, L and Xu, W and Rybtke, M and Tolker-Nielsen, T and Heo, W and Kim, JJ and Kang, NY and Joo, T and Yang, L and Park, SJ and Givskov, M and Chang, YT},
title = {Visualizing biofilm by targeting eDNA with long wavelength probe CDr15.},
journal = {Biomaterials science},
volume = {7},
number = {9},
pages = {3594-3598},
doi = {10.1039/c9bm00152b},
pmid = {31329200},
issn = {2047-4849},
abstract = {Detection of the biofilm of bacteria would be a counter strategy to detect hidden bacteria in their camouflage. Through unbiased screening of bacteria biofilm, we discovered a long wavelength probe CDr15 with extracellular DNA as the molecular target. CDr15 revealed a real-time geometric distribution of eDNA in a 3D bacterial colony.},
}
@article {pmid31328358,
year = {2019},
author = {Qiu, H and Pu, F and Liu, Z and Deng, Q and Sun, P and Ren, J and Qu, X},
title = {Depriving Bacterial Adhesion-Related Molecule to Inhibit Biofilm Formation Using CeO2 -Decorated Metal-Organic Frameworks.},
journal = {Small (Weinheim an der Bergstrasse, Germany)},
volume = {15},
number = {36},
pages = {e1902522},
doi = {10.1002/smll.201902522},
pmid = {31328358},
issn = {1613-6829},
support = {21871249//National Natural Science Foundation of China/ ; 21673223//National Natural Science Foundation of China/ ; 21431007//National Natural Science Foundation of China/ ; 21533008//National Natural Science Foundation of China/ ; 21820102009//National Natural Science Foundation of China/ ; //Key Program of Frontier of Sciences/ ; QYZDJ-SSW-SLH052//CAS/ ; },
abstract = {The formation of bacterial biofilm is one of the causes of antimicrobial resistance, often leading to persistent infections and a high fatality rate. Therefore, there is an urgent need to develop novel and effective strategies to inhibit biofilm formation. Adenosine triphosphate (ATP) plays an important role in bacterial adhesion and biofilm formation through stimulating cell lysis and extracellular DNA (eDNA) release. Herein, a simple and robust strategy for inhibiting biofilm formation is developed using CeO2 -decorated porphyrin-based metal-organic frameworks (MOFs). The function of extracellular ATP (eATP) can be inhibited by CeO2 nanoparticles, leading to the disruption of the initial adhesion of bacteria. Furthermore, planktonic bacteria can be killed by cytotoxic reactive oxygen species (ROS) generated by MOFs. As a consequence, the synergic effect of eATP deprivation and ROS generation presents excellent capacity to prevent biofilm formation, which may provide a new direction for designing flexible and effective biofilm-inhibiting systems.},
}
@article {pmid31328252,
year = {2019},
author = {Bazzoli, A and Plateau, J and Turney, A},
title = {Improvement of microbial ecosystem in livestock animal environment: concept of positive biofilm using an example in swine farrowing.},
journal = {Australian veterinary journal},
volume = {97},
number = {9},
pages = {361},
doi = {10.1111/avj.12808},
pmid = {31328252},
issn = {1751-0813},
}
@article {pmid31326562,
year = {2019},
author = {Sowndarya, J and Farisa Banu, S and Madhura, G and Yuvalakshmi, P and Rubini, D and Bandeira Junior, G and Baldisserotto, B and Vadivel, V and Nithyanand, P},
title = {Agro food by-products and essential oil constituents curtail virulence and biofilm of Vibrio harveyi.},
journal = {Microbial pathogenesis},
volume = {135},
number = {},
pages = {103633},
doi = {10.1016/j.micpath.2019.103633},
pmid = {31326562},
issn = {1096-1208},
abstract = {Vibrio harveyi causes severe loss to the aquaculture industry due to its virulence, which is mediated by Quorum sensing (QS) and biofilm formation. In the current study, we have explored the anti-virulent properties and biofilm disruption ability of luteolin (extracted from coconut shell) and linalool against this important aquaculture pathogen. HPLC analysis of the methanolic extract of coconut shells revealed a single major peak which matched to the standard luteolin which was further elucidated by NMR studies. Further, luteolin and linalool were screened for their ability to inhibit biofilms and various quorum sensing mediated virulence factors of V. harveyi. The Minimum Inhibitory Concentration (MIC) of the two compounds was determined and the sub-inhibitory concentrations of the compounds were able to inhibit biofilm formation. Both the compounds disrupted about 60-70% mature biofilms, which was also visually observed by light microscopy. Both linalool and luteolin exhibited a significant reduction in the production of EPS and alginate in the biofilms matrix of V. harveyi which was confirmed by Scanning Electron Microscopy (SEM). Both compounds inhibited the swarming and swimming motility, the crucial quorum sensing (QS) mediated virulence of V. harveyi. The present study shows the presence of valuable polyphenolic compound like luteolin in coconut shells that are discarded as a waste. From the present study we envisage that luteolin and linalool can serve as potent anti-virulent agents to combat QS mediated infections against aquaculture pathogens.},
}
@article {pmid31325779,
year = {2019},
author = {Borah, SN and Sen, S and Goswami, L and Bora, A and Pakshirajan, K and Deka, S},
title = {Rice based distillers dried grains with solubles as a low cost substrate for the production of a novel rhamnolipid biosurfactant having anti-biofilm activity against Candida tropicalis.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {182},
number = {},
pages = {110358},
doi = {10.1016/j.colsurfb.2019.110358},
pmid = {31325779},
issn = {1873-4367},
abstract = {In this study, rhamnolipid (RL) production by Pseudomonas aeruginosa SS14 utilizing rice based Distillers Dried Grains with Solubles (rDDGS) as the sole carbon source was evaluated and the production parameters were optimized using response surface methodology. Highest RL (RL-rDDGS) yield was 14.87 g/L in a culture medium containing 12% (w/v) rDDGS and 11% (v/v) inoculum concentration after 48 h of fermentation at 35 °C. RL-rDDGS was produced as a mixture of mono and di-RL congeners with four novel homologues Rha-C18:2, Rha-C19, Rha-C9, and Rha-Rha-C19. The RL reduced the surface tension of water to 34.8 mN/m at a critical micelle concentration (CMC) value of 100 mg/L, exhibited high stability at a wide range of pH (6-12), heating time (0-120 min), and salinity (2-12% NaCl). Furthermore, RL-rDDGS demonstrated appreciable biofilm disruptive property against Candida tropicalis. This is the first report on the usage of rDDGS for sustainable and low cost production of RL.},
}
@article {pmid31324055,
year = {2019},
author = {Shi, Z and Dittoe, DK and Feye, KM and Kogut, M and Ricke, SC},
title = {Short Communication: Preliminary Differences Identified in Genes Responsible for Biofilm Formation in Poultry Isolates of Salmonella enterica Heidelberg, Enteritidis, and Kentucky.},
journal = {Microorganisms},
volume = {7},
number = {7},
pages = {},
doi = {10.3390/microorganisms7070196},
pmid = {31324055},
issn = {2076-2607},
abstract = {Salmonella enterica is one of the most prevalent foodborne pathogens. The large quantity of serovar types results in the colonization of a large spectrum of hosts, with different environmental conditions and hazards. The aim of this study was to evaluate the differences in gene expression (bcsA and csgD) of Salmonella enterica serovars Heidelberg, Kentucky, and Enteritidis during biofilm formation using quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR). Overall, there appeared to be differences in expression between the different serovars with high variation between strains. These data are important as they demonstrate considerable variability in gene expression between serovars and strains of poultry isolates of Salmonella enterica.},
}
@article {pmid31323790,
year = {2019},
author = {Carvalho, DB and Fox, EGP and Santos, DGD and Sousa, JS and Freire, DMG and Nogueira, FCS and Domont, GB and Castilho, LVA and Machado, EA},
title = {Fire Ant Venom Alkaloids Inhibit Biofilm Formation.},
journal = {Toxins},
volume = {11},
number = {7},
pages = {},
doi = {10.3390/toxins11070420},
pmid = {31323790},
issn = {2072-6651},
support = {150895/2010-0//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; },
abstract = {Biofilm formation on exposed surfaces is a serious issue for the food industry and medical health facilities. There are many proposed strategies to delay, reduce, or even eliminate biofilm formation on surfaces. The present study focuses on the applicability of fire ant venom alkaloids (aka 'solenopsins', from Solenopsis invicta) tested on polystyrene and stainless steel surfaces relative to the adhesion and biofilm-formation by the bacterium Pseudomonas fluorescens. Conditioning with solenopsins demonstrates significant reduction of bacterial adhesion. Inhibition rates were 62.7% on polystyrene and 59.0% on stainless steel surfaces. In addition, solenopsins drastically reduced cell populations already growing on conditioned surfaces. Contrary to assumptions by previous authors, solenopsins tested negative for amphipathic properties, thus understanding the mechanisms behind the observed effects still relies on further investigation.},
}
@article {pmid31323501,
year = {2019},
author = {Morgan-Sagastume, F and Jacobsson, S and Olsson, LE and Carlsson, M and Gyllenhammar, M and Sárvári Horváth, I},
title = {Anaerobic treatment of oil-contaminated wastewater with methane production using anaerobic moving bed biofilm reactors.},
journal = {Water research},
volume = {163},
number = {},
pages = {114851},
doi = {10.1016/j.watres.2019.07.018},
pmid = {31323501},
issn = {1879-2448},
abstract = {Oil-contaminated wastewaters are generally treated by a combination of physico-chemical and biological methods. Interest in the anaerobic treatment of oily wastewaters has increased since it complements aerobic treatment and produces energy in the form of methane. The objectives of this study were to characterise the anaerobic process spontaneously occurring in a full-scale storage tank at a facility treating waste oil and oil-contaminated effluents, and to evaluate the applicability of an anaerobic moving bed biofilm reactor (AnMBBR) and an anaerobic contact reactor (ACR) for treating the oil contaminated wastewater feeding the storage tank. Three lab-scale reactors were operated in parallel over 465 days: one mesophilic and one thermophilic AnMBBR, and one thermophilic ACR. The wastewater had a high strength with an average chemical oxygen demand (COD) of 36 g/L with a soluble fraction of 80%. The BOD7/COD ratios varied between 0.1 and 0.5, indicating low aerobic degradability. However, biomethane potential tests indicated some level of anaerobic degradability with methane yields between 150 and 200 NmL/gCOD. The full-scale storage tank operated at low organic loading rates (0.35-0.43 kgCOD/m3d), and long hydraulic retention times (HRT = 83-104 d). In comparison, the AnMBBRs achieved similar COD reductions (60%) as the full-scale tank but at a much shorter HRT of 30 d. Similar efficiency could only be reached at longer HRTs (43 d) in the ACR due to low biomass levels resulting from poor sludge settleability. The methane yield was higher (210 NmLCH4/COD removed) in the AnMBBR operated at 37 °C, compared to the other reactors working at 50 °C (180 NmLCH4/COD removed). This reactor also maintained a higher COD removal (67%) at an increased OLR of 1.1 kgCOD/m3d than the AnMBBR at 50 °C. The microbial composition of the biomass from the full-scale tank and the laboratory reactors provided evidence for the conversion of oil-contaminated wastewater into methane with a relatively high abundance of hydrogenotrophic methanogens.},
}
@article {pmid31323469,
year = {2019},
author = {Qi, X and Liu, P and Liang, P and Hao, W and Li, M and Huang, X},
title = {Dual-signal-biosensor based on luminescent bacteria biofilm for real-time online alert of Cu(II) shock.},
journal = {Biosensors &amp; bioelectronics},
volume = {142},
number = {},
pages = {111500},
doi = {10.1016/j.bios.2019.111500},
pmid = {31323469},
issn = {1873-4235},
abstract = {The development of real-time online warning system for toxicity materials is important to ensure the safety of water supply. This study for the first time constructs luminescent bacteria (Vibrio fischeri) biofilm to deliver both electrical and optical real-time response for Cu(II) toxic shock in a bioelectrochemical system (BES) sensor. Compared to biocathode, bioanode was more suitable as sensitive elements. With three tested concentrations of Cu(II), i.e., 1 mg/L, 3 mg/L and 6 mg/L, electrical signals were raised. But optical signal failed to respond to the lowest concentration, suggesting that electrical signal then was produced by chemical reaction of Cu(II) on the electrode surface. For 3 mg/L and 6 mg/L Cu(II) shock, more rapid optical signals were observed than electrical signal, indicating that both the biofilm's surface and inner was affected. In addition, high concentration of Cu(II) toxic as 6 mg/L caused irreversible damage in the biosensor as there were great fluctuation in the recovery curve and large recovery ratio up to -10.39% for optical signal. These results provided a comparison between optical and electrical signals simultaneously produced by a biosensor and visual evidences for better understanding of the toxicity process in the biosensor.},
}
@article {pmid31323449,
year = {2019},
author = {Li, D and Chen, S and Dou, H and Wu, W and Liu, Q and Zhang, L and Shen, Y and Shu, G and Yuan, Z and Lin, J and Zhang, W and Peng, G and Zhong, Z and Yin, L and Fu, H},
title = {Preparation of cefquinome sulfate cationic proliposome and evaluation of its efficacy on Staphylococcus aureus biofilm.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {182},
number = {},
pages = {110323},
doi = {10.1016/j.colsurfb.2019.06.053},
pmid = {31323449},
issn = {1873-4367},
abstract = {Staphylococcus aureus (S. aureus) has the propensity to form biofilms, which eventually cause antibiotic resistance and treatment failure. Cefquinome sulfate (CS) is an animal-specific antibacterial agent for S. aureus infection. In this work, CS cationic proliposomes (CSCPs) were prepared by solid-dispersion method combined with effervescent hydration to eradicate bacterial biofilm and improve the antibacterial effect of the drug. CSCPs were readily dispersed in water, thereby forming CS cationic liposomes (CSCLs) as a white, uniform suspension. The CSCLs had an encapsulation efficiency (EE) of 63.21%, a drug loading of 4.04%, an average particle size of 201.5 nm, and a positive zeta-potential of 65.29 mV. In vitro release studies showed that CSCLs had good sustained-release behavior. The CS and CSCL minimal inhibitory concentration (MIC) of S. aureus type culture strain were 1 and 0.48 g/mL, respectively. The eradication effect of CS on bacterial biofilm (BBF) was relatively weak during culture in drug-containing medium for 8 h-24 h. However, the CSCL eradication effect on BBF increased gradually, and the clearance rate of CSCLs on BBF was about twice that of CS. The clearance rate reached 81.30% with 2.5 × MIC in 24 h. All these results indicated that CSCLs can significantly improve the eradication effect of cefquinome on biofilm to inhibit bacterial growth.},
}
@article {pmid31323072,
year = {2019},
author = {, },
title = {Correction: Circuit diversification in a biofilm regulatory network.},
journal = {PLoS pathogens},
volume = {15},
number = {7},
pages = {e1007966},
doi = {10.1371/journal.ppat.1007966},
pmid = {31323072},
issn = {1553-7374},
abstract = {[This corrects the article DOI: 10.1371/journal.ppat.1007787.].},
}
@article {pmid31321751,
year = {2019},
author = {Černáková, L and Light, C and Salehi, B and Rogel-Castillo, C and Victoriano, M and Martorell, M and Sharifi-Rad, J and Martins, N and Rodrigues, CF},
title = {Novel Therapies for Biofilm-Based Candida spp. Infections.},
journal = {Advances in experimental medicine and biology},
volume = {},
number = {},
pages = {},
doi = {10.1007/5584_2019_400},
pmid = {31321751},
issn = {0065-2598},
abstract = {The presence of fungal infections continue to grow worldwide, mostly in immunosuppressed patients, and in individuals with continued antimicrobial treatments. Candida spp. are the most common yeasts involved in these disorders, being associated with a high rate of antifungal resistance and an increased ability to form biofilms, which make the treatment of these infections difficult. This review aims to present and discuss the main biofilm-related infections cause by several Candida spp. and novel therapies that are currently available in the clinical, scientific and academic environment. New drugs with promising antifungal activity, natural approaches (e.g. probiotics, essential oils, plant extracts, honey) and a final consideration on alternative methodologies, such as photodynamic therapy are presented and discussed.},
}
@article {pmid31321337,
year = {2019},
author = {Pakshir, K and Sheykhi, S and Zomorodian, K and Nouraei, H and Zare Shahrabadi, Z},
title = {Evaluation of biofilm formation in the homozygous and heterozygous strains of vaginal Candida albicans isolates.},
journal = {Current medical mycology},
volume = {5},
number = {2},
pages = {37-40},
doi = {10.18502/cmm.5.2.1160},
pmid = {31321337},
issn = {2423-3439},
abstract = {Background and Purpose: Candida albicans is one of the most opportunistic yeasts around the world. This species has two heterozygous and homozygous strains at hyphal wall protein 1 (hwp1) gene locus. A simple method for the discrimination of these two strains is the amplification of HWP1 gene. Regarding this, the aim of this study was to discriminate C. albicans heterozygous and homozygous strains via the amplification of hwp1 gene and evaluation of biofilm formation between the strains.<br><br>Materials and Methods: A total of 60 homozygous (n=30) and heterozygous (n=30) strains were discriminated among 126 C. albicans vaginal isolates by the amplification of HWP1 gene, using specific primers. The evaluation of biofilm formation was accomplished using the visual method.<br><br>Results: According to the results, the homozygous and heterozygous strains produced one and two DNA fragments, respectively. The frequency of homozygous strains among the C. albicans vaginal isolates was 76.2%. Biofilm formation activity in the heterozygous strains was more than that in the homozygous strains. However, statistical analysis showed no significant difference between the strains in terms of biofilm formation.<br><br>Conclusion: As the findings indicated, the frequency of the heterozygous strains in C. albicans was lower than that of the homozygous strains. Both of the strains could form biofilm in the different ranges of severity. High activity of biofilm formation in heterozygous strains may set the ground for its pathogenicity.},
}
@article {pmid31320183,
year = {2019},
author = {Lee, MJ and Kwon, JS and Kim, JY and Ryu, JH and Seo, JY and Jang, S and Kim, KM and Hwang, CJ and Choi, SH},
title = {Bioactive resin-based composite with surface pre-reacted glass-ionomer filler and zwitterionic material to prevent the formation of multi-species biofilm.},
journal = {Dental materials : official publication of the Academy of Dental Materials},
volume = {35},
number = {9},
pages = {1331-1341},
doi = {10.1016/j.dental.2019.06.004},
pmid = {31320183},
issn = {1879-0097},
abstract = {OBJECTIVE: This study evaluated the synergetic effect between surface pre-reacted glass-ionomer (SPRG) filler and 2-methacryloyloxyethyl phosphorylcholine (MPC), for inhibiting multi-species biofilm formation, while maintaining or even improving the original beneficial features of SPRG-filled resin-based composite (RBC).<br><br>METHODS: MPC (1.5-10wt%) was incorporated into commercial SPRG-filled RBC. Then, the inherent properties of RBC, and ion release and acid-neutralising properties associated with SPRG were investigated. Further, protein adsorptions and bacterial adhesion and viability on the SPRG-filled RBC surfaces were studied using four kinds of oral bacteria; Streptococcus mutans, Actinomyces naeslundii, Veillonella parvula, and Porphyromonas gingivalis. Finally, the thickness and biomass of the human saliva-derived biofilm model cultured on test and control samples were analysed.<br><br>RESULTS: Addition of MPC content resulted in decreased flexural strength and wettability of SPRG-filled RBC. SPRG-filled RBC released significantly higher amounts of multiple ions as contents of MPC increased. Meanwhile, SPRG-filled RBC with 5-wt% MPC significantly improved acid-neutralising properties than those of other test and control samples (P<0.001). SPRG-filled RBC with 3wt% MPC significantly reduced the amount of adsorbed bovine serum albumin and proteins from the brain heart infusion medium as compared to the control (P<0.01). A similar trend was observed in the attachment of four types of bacteria and multi-species biofilm (P<0.01).<br><br>SIGNIFICANCE: Despite limitation in terms of deteriorations of some physical properties, addition of 3% MPC to SPRG-filled RBC leads to inhibition of the attachment of multi-species bacteria on its surface, as well as inhibition of biofilm growth. Moreover, the original important bioactive features of SPRG-filled RBC such as ion release and acid neutralisations are either maintained or improved upon adding MPC.},
}
@article {pmid31319827,
year = {2019},
author = {Ahmed, AA and Salih, FA},
title = {Quercus infectoria gall extracts reduce quorum sensing-controlled virulence factors production and biofilm formation in Pseudomonas aeruginosa recovered from burn wounds.},
journal = {BMC complementary and alternative medicine},
volume = {19},
number = {1},
pages = {177},
doi = {10.1186/s12906-019-2594-5},
pmid = {31319827},
issn = {1472-6882},
abstract = {BACKGROUND: Quercus gall extracts' ability to kill pathogens in vitro and even removal of chronic drug-resistant infections has been reported by several studies. The current investigation is focused on the action of extracts of Quercus infectoria gall in their sub-inhibitory concentrations on the corresponding bacterial behaviours instead of killing them.<br><br>METHODS: The effect of gall extracts on the quorum sensing (QS) associated virulence of multiple drug resistant Pseudomonas aeruginosa recovered from burns wounds was studied. The influence of different extracts on the production of bacterial virulence and biofilm, and expression of the genes encoding quorum sensing and exotoxin A were investigated. Quorum sensing is a crucial regulator of virulence and biofilm development in Pseudomonas aeruginosa and other medical related microbes.<br><br>RESULTS: Experiments to characterise and quantify Q. infectoria gall extracts impact on the quorum sensing networks of P.aeruginosa revealed that the expression of las, rhl, and exotoxin A (ETA) genes levels including the associated virulence were reduced by the extracts at their subinhibitory concentrations.<br><br>CONCLUSIONS: The obtained results indicated that extracts of Q. infectoria galls fight infections either by their inhibitory constituents, which vigorously eradicate cells or by disruption of the pathogens quorum sensing system through weakening the virulence and bacterial coordination.},
}
@article {pmid31319670,
year = {2019},
author = {Balasubramanian, S and Aubin-Tam, ME and Meyer, AS},
title = {3D Printing for the Fabrication of Biofilm-Based Functional Living Materials.},
journal = {ACS synthetic biology},
volume = {8},
number = {7},
pages = {1564-1567},
doi = {10.1021/acssynbio.9b00192},
pmid = {31319670},
issn = {2161-5063},
abstract = {Bacterial biofilms are three-dimensional networks of cells entangled in a self-generated extracellular polymeric matrix composed of proteins, lipids, polysaccharides, and nucleic acids. Biofilms can establish themselves on virtually any accessible surface and lead to varying impacts ranging from infectious diseases to degradation of toxic chemicals. Biofilms exhibit high mechanical stiffness and are inherently tolerant to adverse conditions including the presence of antibiotics, pollutants, detergents, high temperature, changes in pH, etc. These features make biofilms resilient, which is beneficial for applications in dynamic environments such as bioleaching, bioremediation, materials production, and wastewater purification. We have recently described an easy and cost-effective method for 3D printing of bacteria and have extended this technology for 3D printing of genetically engineered Escherichia coli biofilms. Our 3D printing platform exploits simple alginate chemistry for printing of a bacteria-alginate bioink mixture onto calcium-containing agar surfaces, resulting in the formation of bacteria-encapsulating hydrogels with varying geometries. Bacteria in these hydrogels remain intact, spatially patterned, and viable for several days. Printing of engineered bacteria to produce inducible biofilms leads to formation of multilayered three-dimensional structures that can tolerate harsh chemical treatments. Synthetic biology and material science approaches provide the opportunity to append a wide range of useful functionalities to these 3D-printed biofilms. In this article, we describe the wide range of future applications possible for applying functional 3D-printed biofilms to the construction of living biofilm-derived materials in a large-scale and environmentally stable manner.},
}
@article {pmid31319057,
year = {2019},
author = {Narayana, JL and Mishra, B and Lushnikova, T and Golla, RM and Wang, G},
title = {Modulation of antimicrobial potency of human cathelicidin peptides against the ESKAPE pathogens and in vivo efficacy in a murine catheter-associated biofilm model.},
journal = {Biochimica et biophysica acta. Biomembranes},
volume = {1861},
number = {9},
pages = {1592-1602},
doi = {10.1016/j.bbamem.2019.07.012},
pmid = {31319057},
issn = {1879-2642},
support = {R01 AI105147/AI/NIAID NIH HHS/United States ; R56 AI105147/AI/NIAID NIH HHS/United States ; },
abstract = {Antimicrobial peptides are essential components of innate immune systems that protect hosts from infection. They are also useful candidates for developing a new generation of antibiotics to fight antibiotic-resistant pathogens. Human innate immune peptide LL-37 can inhibit biofilm formation, but suffers from high cost due to a long peptide length and rapid protease degradation. To improve the peptide, we previously identified the major active region and changed the peptide backbone structure. This study designed two families of new peptides by altering peptide side chains. Interestingly, these peptides displayed differential potency against various ESKAPE pathogens in vitro and substantially reduced hemolysis. Further potency test in vivo revealed that 17tF-W eliminated the burden of methicillin-resistant Staphylococcus aureus (MRSA) USA300 in both mouse-embedded catheters and their surrounding tissues. In addition, peptide treatment suppressed the level of chemokine TNFα, and boosted the levels of chemokines MCP-1, IL-17A and IL-10 in the surrounding tissues of the infected catheter embedded in mice. In conclusion, we have designed a set of new LL-37 peptides with varying antimicrobial activities, opening the door to potential topical treatment of infections involving different drug-resistant pathogens.},
}
@article {pmid31318574,
year = {2019},
author = {Patel, KK and Surekha, DB and Tripathi, M and Anjum, MM and Muthu, MS and Tilak, R and Agrawal, AK and Singh, S},
title = {Antibiofilm Potential of Silver Sulfadiazine-Loaded Nanoparticle Formulations: A Study on the Effect of DNase-I on Microbial Biofilm and Wound Healing Activity.},
journal = {Molecular pharmaceutics},
volume = {16},
number = {9},
pages = {3916-3925},
doi = {10.1021/acs.molpharmaceut.9b00527},
pmid = {31318574},
issn = {1543-8392},
abstract = {Biofilm resistance is one of the severe complications associated with chronic wound infections, which impose extreme microbial tolerance against antibiotic therapy. Interestingly, deoxyribonuclease-I (DNase-I) has been empirically proved to be efficacious in improving the antibiotic susceptibility against biofilm-associated infections. DNase-I hydrolyzes the extracellular DNA, a key component of the biofilm responsible for the cell adhesion and strength. Moreover, silver sulfadiazine, a frontline therapy in burn wound infections, exhibits delayed wound healing due to fibroblast toxicity. In this study, a chitosan gel loaded with solid lipid nanoparticles of silver sulfadiazine (SSD-SLNs) and supplemented with DNase-I has been developed to reduce the fibroblast cytotoxicity and overcome the biofilm-imposed resistance. The extensive optimization using the Box-Behnken design (BBD) resulted in the formation of SSD-SLNs with a smooth surface as confirmed by scanning electron microscopy and controlled release (83%) for up to 24 h. The compatibility between the SSD and other formulation excipients was confirmed by Fourier transform infrared, differential scanning calorimetry, and powder X-ray diffraction studies. Developed SSD-SLNs in combination with DNase-I inhibited around 96.8% of biofilm of Pseudomonas aeruginosa as compared to SSD with DNase-I (82.9%). In line with our hypothesis, SSD-SLNs were found to be less toxic (cell viability 90.3 ± 3.8% at 100 μg/mL) in comparison with SSD (Cell viability 76.9 ± 4.2%) against human dermal fibroblast cell line. Eventually, the results of the in vivo wound healing study showed complete wound healing after 21 days' treatment with SSD-SLNs along with DNase-I, whereas marketed formulations SSD and SSD-LSNs showed incomplete healing after 21 days. Data in hand suggest that the combination of SSD-SLNs with DNase-I is an effective treatment strategy against the biofilm-associated wound infections and accelerates wound healing.},
}
@article {pmid31318043,
year = {2019},
author = {Alsahhaf, A and Al-Aali, KA and Alshagroud, RS and Alshiddi, IF and Alrahlah, A and Abduljabbar, T and Javed, F and Vohra, F},
title = {Comparison of yeasts species in the subgingival oral biofilm of type 2-diabetic and non-diabetic individuals with peri-implantitis.},
journal = {Journal of periodontology},
volume = {},
number = {},
pages = {},
doi = {10.1002/JPER.19-0091},
pmid = {31318043},
issn = {1943-3670},
abstract = {BACKGROUND: There are no studies that have investigated the presence of yeasts in the subgingival oral biofilm (OB) of type-2 diabetic and non-diabetic patients with peri-implantitis. The aim was to assess the presence of yeasts in the subgingival OB of type-2 diabetic and non-diabetic patients with peri-implantitis.<br><br>MATERIALS AND METHODS: Type-2 diabetic individuals with peri-implantitis (Group-A), non-diabetic individuals with peri-implantitis (Group-B) and non-diabetic individuals without peri-implantitis (Group-C) were included. Life style related and demographic data was collected using a questionnaire and hemoglobin A1c levels were measured. Peri-implant plaque-index (PI), bleeding-on-probing (BOP) and probing-depth (PD) were evaluated and crestal bone loss (CBL) were measured. Subgingival OB samples were collected, and oral yeasts species were identified using ChromAgar medium. Level of significance was set at P < 0.05.<br><br>RESULTS: The mean age of individuals in groups A (n = 43), B (n = 41) and C (n = 42) were 55.6 ± 6.4, 54.6 ± 4.5 and 57.1 ± 3.3 years, respectively. The mean HbA1c levels were higher in Group-A (P < 0.01) than groups B and C. Peri-implant PI (P < 0.01), BOP (P < 0.01), PD (P < 0.01) and CBL (P < 0.01) were significantly higher in Group-A compared with patients in groups B and C. Peri-implant PI (P < 0.05), BOP (P < 0.05), PD (P < 0.05) and CBL (P < 0.05) were significantly higher among patients in Group-B compared with Group-C. Subgingival yeasts were more often isolated from the OB of patients in groups A (74.4%) and B (46.3%) than Group-C (7.1%). The most common yeast species identified in all groups was Candida albicans (C. albicans). The CFU/ml for subgingival yeasts were higher in Group-A than groups B (P < 0.01) and C (P < 0.01). The CFU/ml for subgingival yeasts were higher in Group-B than Group-C (P < 0.01).<br><br>CONCLUSION: Candida species (predominantly C. albicans) were more often present in the subgingival OB of type-2 diabetic and non-diabetic patients with peri-implantitis than systemically healthy individuals without peri-implant diseases. This article is protected by copyright. All rights reserved.},
}
@article {pmid31315967,
year = {2019},
author = {Sherman, E and Bayles, K and Moormeier, D and Endres, J and Wei, T},
title = {Observations of Shear Stress Effects on Staphylococcus aureus Biofilm Formation.},
journal = {mSphere},
volume = {4},
number = {4},
pages = {},
doi = {10.1128/mSphere.00372-19},
pmid = {31315967},
issn = {2379-5042},
abstract = {Staphylococcus aureus bacteria form biofilms and distinctive microcolony or &quot;tower&quot; structures that facilitate their ability to tolerate antibiotic treatment and to spread within the human body. The formation of microcolonies, which break off, get carried downstream, and serve to initiate biofilms in other parts of the body, is of particular interest here. It is known that flow conditions play a role in the development, dispersion, and propagation of biofilms in general. The influence of flow on microcolony formation and, ultimately, what factors lead to microcolony development are, however, not well understood. The hypothesis being examined is that microcolony structures form within a specific range of levels of shear stress. In this study, laminar shear flow over a range of 0.15 to 1.5 dynes/cm2 was examined. It was found that microcolony structures form in a narrow range of shear stresses around 0.6 dynes/cm2 Further, measurements of cell density as a function of space and time showed that shear dependence can be observed hours before microcolonies form. This is significant because, among other physiologic flows, this is the same shear stress found in large veins in the human vasculature, which, along with catheters of similar diameters and flow rates, may therefore play a critical role in biofilm development and subsequent spreading of infections throughout the body.IMPORTANCE It is well known that flow plays an important role in the formation, transportation, and dispersion of Staphylococcus aureus biofilms. What was heretofore not known was that the formation of tower structures in these biofilms is strongly shear stress dependent; there is, in fact, a narrow range of shear stresses in which the phenomenon occurs. This work quantifies the observed shear dependence in terms of cell growth, distribution, and fluid mechanics. It represents an important first step in opening up a line of questioning as to the interaction of fluid forces and their influence on the dynamics of tower formation, break-off, and transportation in biofilms by identifying the parameter space in which this phenomenon occurs. We have also introduced state-of-the-art flow measurement techniques to address this problem.},
}
@article {pmid31315572,
year = {2019},
author = {Zeighami, H and Valadkhani, F and Shapouri, R and Samadi, E and Haghi, F},
title = {Virulence characteristics of multidrug resistant biofilm forming Acinetobacter baumannii isolated from intensive care unit patients.},
journal = {BMC infectious diseases},
volume = {19},
number = {1},
pages = {629},
doi = {10.1186/s12879-019-4272-0},
pmid = {31315572},
issn = {1471-2334},
abstract = {BACKGROUND: Nosocomial infections and persistence of multidrug resistant biofilm forming Acinetobacter baumannii in hospitals has made it as a serious problem in healthcare settings worldwide.<br><br>METHODS: A total of 100 A. baumannii clinical isolates from immunocompromised patients hospitalized in ICU were investigated for biofilm formation, the presence of biofilm related genes (bap, ompA, csuE, fimH, epsA, blaPER-1, bfmS, ptk, pgaB, csgA, kpsMII), integron characterization and molecular typing based on REP-PCR.<br><br>RESULTS: All isolates were resistant to three or more categories of antibiotics and considered as multidrug resistant (MDR). A total of 32 isolates were resistant to all tested antibiotics and 91% were extensively drug-resistance (XDR). All isolates were able to produce biofilm and 58% of isolates showed strong ability to biofilm formation. All strong biofilm forming A. baumannii isolates were XDR. All A. baumannii isolates carried at least one biofilm related gene. The most prevalent gene was csuE (100%), followed by pgaB (98%), epsA and ptk (95%), bfmS (92%) and ompA (81%). 98% of isolates carried more than 4 biofilm related genes, simultaneously. Class I integron (67%) was more frequent in comparison with class II (10%) (P < 0.05). The REP-PCR patterns were classified as 8 types (A-H) and 21 subtypes. The A1 (23%) and C1 (15%) clusters were the most prevalent among A. baumannii isolates (P < 0.05). According to the REP-PCR patterns, 23% of all isolates had a clonal relatedness.<br><br>CONCLUSION: Our study revealed the high frequency of biofilm forming XDR A. baumannii in ICU patients, with a high prevalence of biofilm related genes of csuE and pgaB. It seems that the appropriate surveillance and control measures are essential to prevent the emergence and transmission of XDR A. baumannii in our country.},
}
@article {pmid31314663,
year = {2019},
author = {Sianglum, W and Muangngam, K and Joycharat, N and Voravuthikunchai, SP},
title = {Mechanism of Action and Biofilm Inhibitory Activity of Lupinifolin Against Multidrug-Resistant Enterococcal Clinical Isolates.},
journal = {Microbial drug resistance (Larchmont, N.Y.)},
volume = {},
number = {},
pages = {},
doi = {10.1089/mdr.2018.0391},
pmid = {31314663},
issn = {1931-8448},
abstract = {The treatment of enterococcal infections is becoming more difficult because of multidrug resistance (MDR). Lupinifolin, a prenylated flavonoid isolated from Albizia myriophylla Benth., showed a potent antimicrobial activity against enterococci. The aim of this study was to investigate antibacterial activity and action of lupinifolin against MDR enterococcal clinical isolates. Antibacterial properties of lupinifolin against 21 MDR isolates were assessed using broth microdilution method and time-kill assay. To study mode of action of lupinifolin on the isolates, propidium iodide intensity, salt tolerance assay, and electron microscopic analyses were performed. Antibiofilm formation activity of lupinifolin was conducted using crytal violet assay. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration values of lupinifolin against the isolates ranged between 0.5 and 2.0 μg/mL and between 2 and 16 μg/mL, respectively. Lupinifolin at 2MIC and 4MIC inhibited the bacterial growth >2 log colony-forming units (CFU)/mL at 2 hr incubation by time-kill analysis. The compound increased membrane permeability and caused loss of salt tolerance. SEM and TEM micrographs revealed pronounced morphological and ultrastructural changes in the treated bacteria. Crystal violet staining showed the antibiofilm-producing activity of lupinifolin against four MDR enterococci. This study suggested that lupinifolin is an essential antimicrobial agent that could be useful for the treatment of MDR enterococcal infections.},
}
@article {pmid31313963,
year = {2019},
author = {Khelissa, SO and Abdallah, M and Jama, C and Barras, A and Chihib, NE},
title = {Comparative Study on the Impact of Growth Conditions on the Physiology and the Virulence of Pseudomonas aeruginosa Biofilm and Planktonic Cells.},
journal = {Journal of food protection},
volume = {82},
number = {8},
pages = {1357-1363},
doi = {10.4315/0362-028X.JFP-18-565},
pmid = {31313963},
issn = {1944-9097},
abstract = {The aim of the present work was to study and compare the effect of growth temperature (20, 30, and 37°C) and surface type (stainless steel and polycarbonate) on the production of virulence factors, such as proteases and siderophores, and the risk of surface contamination associated with Pseudomonas aeruginosa biofilm and planktonic cells. The increase of growth temperature from 20 to 37°C increased (approximately twofold) the electronegative charge and the hydrophobicity of the P. aeruginosa biofilm cell surface. P. aeruginosa biofilm cell adhesion to stainless steel and polycarbonate was 5- and 1.5-fold higher than their planktonic counterparts at 20 and 30°C, respectively. The increase of growth temperature from 20 to 37°C increased the production of proteases (twofold) and siderophores (twofold) and the cytotoxicity (up to 30-fold) against the HeLa cell line in the supernatants of P. aeruginosa planktonic and biofilm cultures. This study also highlighted that biofilm and planktonic P. aeruginosa cells exhibited distinct physiological properties with respect to the production of virulence factors and the cytotoxicity against the Hela cell line. Therefore, effective disinfection procedures should be adapted to inactivate bacteria detached from biofilms.},
}
@article {pmid31312343,
year = {2019},
author = {Wei, Q and Zhang, Z and Luo, J and Kong, J and Ding, Y and Chen, Y and Wang, K},
title = {Insulin treatment enhances pseudomonas aeruginosa biofilm formation by increasing intracellular cyclic di-GMP levels, leading to chronic wound infection and delayed wound healing.},
journal = {American journal of translational research},
volume = {11},
number = {6},
pages = {3261-3279},
pmid = {31312343},
issn = {1943-8141},
abstract = {Diabetes-related infections have become challenging and important public health problems in China and around the world. P. aeruginosa plays an important role in diabetic foot infections. As a gram-negative opportunistic pathogen, P. aeruginosa causes recurrent and refractory infections that are characterized by biofilm formation. Previous studies have demonstrated that biofilm-challenged wounds typically take longer to heal than non-biofilm-challenged normal wounds in diabetic mouse models. In the present study, we sought to explore the mechanism via which insulin treatment affects cyclic di-GMP signaling in P. aeruginosa-infected chronic wounds in db/db diabetic mice. We found that the wounds of diabetic mice healed more slowly than those of nondiabetic mice. Moreover, wound healing in diabetic mice treated with insulin exhibited a considerable delay. Peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) was used to detect biofilms on P. aeruginosa-infected wound tissues. Increased intracellular c-di-GMP levels promoted biofilm formation in wound tissues from nondiabetic mice. Greater biofilm formation was observed in the wounds of insulin-treated diabetic mice than in the wounds of untreated diabetic mice or nondiabetic mice, in both the PAO1/plac-yhjH- and PAO1-infected groups. Quantitative RT-PCR indicated that upon infection with PAO1/Plac-yhjH (the low c-di-GMP expression strain), the expression of IL-4 RNA was significantly higher in diabetic mice treated with insulin than in untreated diabetic mice or nondiabetic mice at each observation time point. Peak expression of IFN-γ occurred earlier in diabetic mice treated with insulin than in untreated diabetic mice with each of the experimental strains. Finally, P. aeruginosa harboring the plasmid pCdrA: gfps was used as a reporter strain to monitor c-di-GMP levels. We found that insulin could promote biofilm formation by increasing intracellular c-di-GMP levels in vitro. Taken together, these data demonstrate that insulin treatment increases intracellular c-di-GMP levels, promotes biofilm formation and prolongs the inflammation period during the healing of infected wounds, resulting in delayed wound healing.},
}
@article {pmid31311139,
year = {2019},
author = {Nóbrega, V and Faria, M and Quintana, A and Kaufmann, M and Ferreira, A and Cordeiro, N},
title = {From a Basic Microalga and an Acetic Acid Bacterium Cellulose Producer to a Living Symbiotic Biofilm.},
journal = {Materials (Basel, Switzerland)},
volume = {12},
number = {14},
pages = {},
doi = {10.3390/ma12142275},
pmid = {31311139},
issn = {1996-1944},
support = {REBECA (MAC/1.1a/060)//European Territorial Cooperation Programme PCT-MAC 2014-2020/ ; M1420-01-0145-FEDER-000001//Oceanic Observatory of Madeira/ ; },
abstract = {Bacterial cellulose (BC) has recently been the subject of a considerable amount of research, not only for its environmentally friendly biosynthesis, but also for its high potential in areas such as biomedicine or biomaterials. A symbiotic relationship between a photosynthetic microalga, Chlamydomonas debaryana, and a cellulose producer bacterium, Komagataeibacter saccharivorans, was established in order to obtain a viable and active biofilm. The effect of the growth media composition ratio on the produced living material was investigated, as well as the microalgae biomass quantity, temperature, and incubation time. The optimal temperature for higher symbiotic biofilm production was 30 °C with an incubation period of 14 days. The high microalgae presence, 0.75% w/v, and 60:40 HS:BG-11 medium (v/v) induced a biofilm microalgae incorporation rate of 85%. The obtained results report, for the first time, a successful symbiotic interaction developed in situ between an alkaline photosynthetic microalga and an acetic acid bacterium. These results are promising and open a new window to BC living biofilm applications in medical fields that have not yet been explored.},
}
@article {pmid31310825,
year = {2019},
author = {Cusicanqui Méndez, DA and Gutierrez, E and Campos Chaves Lamarque, G and Lopes Rizzato, V and Afonso Rabelo Buzalaf, M and Andrade Moreira Machado, MA and Cruvinel, T},
title = {The effectiveness of curcumin-mediated antimicrobial photodynamic therapy depends on pre-irradiation and biofilm growth times.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {27},
number = {},
pages = {474-480},
doi = {10.1016/j.pdpdt.2019.07.011},
pmid = {31310825},
issn = {1873-1597},
abstract = {BACKGROUND: The aim of this study was to determine the influence of distinct pre-irradiation times (PIT) of curcumin on the effectiveness of antimicrobial photodynamic therapy (aPDT) against intact dentin caries biofilms grown for 3 or 5 days.<br><br>METHODS: The microcosm biofilms grew on non-fluorescent glass blocks immersed in McBain medium with 1% sucrose, using microaerophilic conditions at 37 °C for 3 or 5 days. The biofilms were treated by the association of 600 μmol.L-1 curcumin using different pre-irradiation times (1, 2 or 5 min) combined with 0 or 75 J.cm-2 blue LED. Then, the vitality of biofilms was determined by confocal scanning laser microscopy (CSLM), after being stained with the mixture of ethidium bromide and fluorescein diacetate. Statistical analysis was performed by two-way ANOVA and post-hoc Tukey tests, after arcsine transformation (P < 0,05).<br><br>RESULTS: In comparison to control, curcumin alone (PIT = 5 min) and all combinations of curcumin and LED reduced significantly the vitality of 3-day biofilms. Distinctly, only curcumin plus LED using PITs of 2 or 5 min were effective in reducing the vitality of 5-day biofilms.<br><br>CONCLUSION: Curcumin-mediated aPDT significantly decreased the vitality of intact dentin caries microcosms grown during 3 or 5 days, although successful treatments of 5-day biofilms required longer PITs in comparison to their counterparts.},
}
@article {pmid31303882,
year = {2019},
author = {Bahari, M and Ebrahimi Chaharom, ME and Daneshpooy, M and Gholizadeh, S and Pashayi, H},
title = {Effect of bleaching protocols on surface roughness and biofilm formation on silorane-based composite resin.},
journal = {Dental research journal},
volume = {16},
number = {4},
pages = {264-270},
pmid = {31303882},
issn = {1735-3327},
abstract = {Background: Knowledge about the effect of bleaching on behavior of composite resins is important to find a suitable composite resin for restoration of teeth undergoing bleaching. This study aimed to assess the effect of different bleaching protocols on surface roughness and biofilm formation on a silorane-based composite resin.<br><br>Materials and Methods: In this in vitro experimental study, 60 silorane-based composite resin samples measuring 3 mm in thickness and 6 mm in diameter were fabricated and polished. They were then randomly divided into four groups (n = 15). In Group 1, samples were stored in distilled water as control. Samples in Groups 2, 3, and 4 were subjected to bleaching with 15% carbamide peroxide, 35% hydrogen peroxide, and 35% hydrogen peroxide activated by light, respectively. Surface roughness was measured using a profilometer. Streptococcus mutans cultured in brain-heart infusion broth was used for the assessment of biofilm formation on the samples. The bacterial colonies were counted using the pure-plate technique. Data were analyzed using one-way ANOVA and post hoc Tukey's tests. Regression model was used to assess the association between surface roughness and biofilm formation (P < 0.05).<br><br>Results: The mean surface roughness of the four groups was not significantly different (P = 0.11); however, a significant difference was noted in the mean biofilm formation among the groups (P = 0.00).<br><br>Conclusion: Bleaching decreased biofilm formation. The lowest biofilm formation was noted in the group subjected to light-activated 35% hydrogen peroxide. Increased surface roughness enhanced biofilm formation to a certain level; excessive roughness did not increase biofilm formation.},
}
@article {pmid31303772,
year = {2019},
author = {Farajzadeh Sheikh, A and Asareh Zadegan Dezfuli, A and Navidifar, T and Fard, SS and Dehdashtian, M},
title = {Association between biofilm formation, structure and antibiotic resistance in Staphylococcus epidermidis isolated from neonatal septicemia in southwest Iran.},
journal = {Infection and drug resistance},
volume = {12},
number = {},
pages = {1771-1782},
doi = {10.2147/IDR.S204432},
pmid = {31303772},
issn = {1178-6973},
abstract = {Background:Staphylococcus epidermidis has emerged as the pathogen from neonatal septicemia. Antibiotic resistance and the capability of biofilm formation make these infections much harder to treat. Hence, the aim of this study was to investigate the association between biofilm formation, structure and antibiotic resistance in S. epidermidis isolated from neonatal septicemia. Methods: Overall, 65 S. epidermidis isolates were recovered from blood cultures of neonatal septicemia. Antibiotic resistance pattern and the biofilm production were determined using phenotypic methods. The presence of ica operon, the bhp, the aap genes and SCCmec types were screened using PCR. Results: Most S.epidermidis isolates were resistant to erythromycin, while all isolates were sensitive to linezolid and vancomycin. Fifty-three percent of S.epidermidis isolates were resistant to methicillin. SCCmec types II was found commonly among methicillin-resistant S. epidermidis (MRSE) strains. The biofilm formation was observed in 65% of S.epidermidis isolates and the majority have polysaccharide matrix. icaA and icaD genes were found in 40% and 19% of isolates. Twenty-three isolates (62%) produced dissolvable polysaccharide intercellular adhesion (PIA)-dependent biofilms in SM after growth in TSB with NaCl and 14 (37%) isolates produced dissolvable protein-dependent biofilms in PK after growth in TSB with glucose. Three isolates (62%) produced dissolvable polysaccharide intercellular adhesion. Conclusion: Our data indicate the high rates of antibiotic resistance and the capability of biofilm formation among S. epidermidis isolates. Hence, the transmission of these strains can cause an increased risk of serious nosocomial infections.},
}
@article {pmid31302463,
year = {2019},
author = {Zhang, Q and Zhang, L and Li, Z and Zhang, L and Li, D},
title = {Enhancement of fipronil degradation with eliminating its toxicity in a microbial fuel cell and the catabolic versatility of anodic biofilm.},
journal = {Bioresource technology},
volume = {290},
number = {},
pages = {121723},
doi = {10.1016/j.biortech.2019.121723},
pmid = {31302463},
issn = {1873-2976},
abstract = {The degradation of fipronil was investigated in microbial fuel cells (MFCs). Almost 79% of 30 mg/L fipronil was rapidly degraded within 12 h by MFC biofilm. Based on the constructed quadratic polynomial model, a maximum fipronil degradation rate of 94.22% could be theoretically achieved at pH of 7.01, 33.39 °C, and the initial fipronil concentration 74 mg/L after incubation for 72 h. The high acute toxicity of fipronil toward zebrafish was largely eliminated after degradation by the MFC. In addition, the MFC biofilm showed catabolic versatility to 4-chloronitrobenzene, sulfanilamide, fluoroglycofen, and azoxystrobin. The microbial community analysis revealed that the functional bacteria Sphaerochaeta, Pseudomonas, Azospirillum, Azoarcus, and Chryseobacterium were major predominant bacteria in the anodic biofilm. Therefore, the MFC offers a promising approach in treating the environmental contaminants due to its abilities of energy capture from waste substances and catabolic versatility to different organic compounds.},
}
@article {pmid31300852,
year = {2019},
author = {Zara, G and Bou Zeidan, M and Fancello, F and Sanna, ML and Mannazzu, I and Budroni, M and Zara, S},
title = {The administration of L-cysteine and L-arginine inhibits biofilm formation in wild-type biofilm-forming yeast by modulating FLO11 gene expression.},
journal = {Applied microbiology and biotechnology},
volume = {103},
number = {18},
pages = {7675-7685},
doi = {10.1007/s00253-019-09996-5},
pmid = {31300852},
issn = {1432-0614},
abstract = {Microbial biofilms are undesired in food manufacturing, drinking water distribution systems, and clinical realms. Yeast biofilms are particularly problematic because of the strong capacity of yeast cells to adhere to abiotic surfaces, cells, and tissues. Novel approaches have been developed over recent years to prevent the establishment of microbial biofilms, such as through the use of small molecules with inhibiting and dispersing properties. Here, we studied the inhibitory activity of 11 different amino acids on the biofilm formation ability of three wild-type Saccharomyces cerevisiae strains and the reference strain ∑1278b. Subsequent evaluation of different concentrations of the two most effective amino acids, namely, arginine and cysteine, revealed that they acted in different ways. Arginine prevented biofilm formation by reducing FLO11 gene expression; its addition did not affect cell viability and was even found to enhance cell metabolism (vitality marker) as determined by phenotype microarray (PM) analysis. On the contrary, the addition of cysteine reduced both cell viability and vitality as well as FLO11 expression. Thus, the use of cysteine and arginine as agents against biofilm formation can be diversified depending on the most desired action towards yeast growth.},
}
@article {pmid31300301,
year = {2019},
author = {Uribe-García, A and Paniagua-Contreras, GL and Monroy-Pérez, E and Bustos-Martínez, J and Hamdan-Partida, A and Garzón, J and Alanís, J and Quezada, R and Vaca-Paniagua, F and Vaca, S},
title = {Frequency and expression of genes involved in adhesion and biofilm formation in Staphylococcus aureus strains isolated from periodontal lesions.},
journal = {Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jmii.2019.05.010},
pmid = {31300301},
issn = {1995-9133},
abstract = {BACKGROUND/PURPOSE: The aim of this study was to characterize the Staphylococcus aureus strains isolated from periodontal lesions of patients, to determine the expression of genes involved in cell adhesion upon their infection of human epithelial cells using an in vitro model, its biofilm formation, and its resistance to antibiotics.<br><br>METHODS: S. aureus was analysed by PCR, Kirby-Bauer, and pulsed-field gel electrophoresis (PFGE), measuring gene expression by real-time PCR after infection of human cells in vitro.<br><br>RESULTS: S. aureus was identified in 18.6% (50/268) of the samples. All strains (n = 50) possessed the virulence genes spa (Staphylococcal protein A), coa (coagulase), and icaAB (intercellular adhesin); 96% (n = 48) possessed clfB (clumping factor B), and 88% (n = 44) possessed ebps (elastin-binding protein) and sdrD (serine aspartate repeat protein D). All strains were resistant to methicillin, ampicillin, dicloxacillin, cefotaxime, and penicillin, and were multidrug resistant to 6-12 antibiotics. PFGE analysis showed 37 different pulsed-field types and most strains (60.4%) had a unique pulsed-field type. Twenty-four distinct combinations of virulence genes and antibiotic-resistant phenotypes were identified.<br><br>CONCLUSION: Although S. aureus has been considered a transient member of the oral microbiota, our results indicate a high-level expression of virulence genes and multidrug resistance in the strains isolated from periodontal lesions. These strains might complicate the successful treatment of the disease.},
}
@article {pmid31300167,
year = {2019},
author = {Zhang, K and Lyu, L and Yao, S and Kang, T and Ma, Y and Pan, Y and Chang, M and Wang, Y and Furukawa, K and Zhu, T},
title = {Effects of vibration on anammox-enriched biofilm in a high-loaded upflow reactor.},
journal = {The Science of the total environment},
volume = {685},
number = {},
pages = {1284-1293},
doi = {10.1016/j.scitotenv.2019.06.082},
pmid = {31300167},
issn = {1879-1026},
mesh = {Ammonium Compounds/metabolism ; *Biofilms ; *Bioreactors ; Vibration ; Waste Disposal, Fluid/*methods ; },
abstract = {An upflow biofilm reactor was operated for 211 days to investigate the effects of vibration on anammox treatment performance. With vibration, the highest nitrogen removal rates (20 kg-N·m-3·d-1) were obtained on day 180. Since the vibration could directly applied on the biofilm, it could release the dinitrogen gas accumulated in the biofilm timely and reduce the internal mass transfer resistance sharply. The specific anammox activity increased by more than 3 times with a higher vibration intensity. Meanwhile, the unique random motion caused by mechanical vibration promotes the production of extracellular proteins. Moreover, the VSS reached 20.97 g·L-1 which was 1.6 times higher than the control reactor. Such enrichment method resulted in a hard and thick anammox biofilm with a special granular morphology, and the nitrite tolerance concentration could reach 500 mg-N·L-1. Operated with an adequate vibration intensity could maintain the biofilm thickness and conducive to improve the stability of the reactor. In addition, this technique also allowed the microorganisms inside the biofilm and those on the surface to reach the same culture conditions. Base on the batch experiments, intermittent vibration caused a decrease in energy consumption from about 7.757 (kW·h)·(kg-N)-1 in group 0-Lv7(60-60) to 0.912 (kW·h)·(kg-N)-1 in group 0-Lv7(5-60). Compared to the internal recycle without vibration, the energy consumption fell by a slice over 65%. Furthermore, the high-throughput sequencing results showed that the relative abundance of Candidatus Kuenenia in reactor 1 increased from 13.2% to 43.9%.},
}
@article {pmid31299899,
year = {2019},
author = {Azmi, K and Qrei, W and Abdeen, Z},
title = {Screening of genes encoding adhesion factors and biofilm production in methicillin resistant strains of Staphylococcus aureus isolated from Palestinian patients.},
journal = {BMC genomics},
volume = {20},
number = {1},
pages = {578},
doi = {10.1186/s12864-019-5929-1},
pmid = {31299899},
issn = {1471-2164},
support = {(M33-014).//Merck/ ; },
abstract = {BACKGROUND: Intercellular adhesion and biofilm production by Staphylococcus aureus makes these bacteria resistant to antimicrobial therapy. Here, Methicillin-resistant Staphylococcus aureus (MRSA) strains were characterized and the prevalence of genes encoding adhesion factors and biofilm formation was determined.<br><br>RESULTS: All 248 MRSA isolates identified by cefoxitin disc diffusion were positive for the mecA gene. SCCmec-IV was the most frequently detected genotype (92.7%) and SCCmec-IVa was also very prevalent (84.3%). The quantitative microtiter plate assay showed that all the isolates were able to produce biofilm with levels ranging from high (21%) to moderate (46.4%) to low (32.7%). All the strains possessed the icaD/icaA genes and produced biofilm (P < 0.05). None of the isolates possessed the bap gene. Furthermore, 94.8% of the isolates were positive for eno, 80.2% for clfA and for clfB, 78.2% for fnbA, 76.2% for ebps, 62.2% for fib, 39.9% for cna and 29.0% for fnbB. Also, nearly 69.8% of the isolates were positive for the gene sarA. All four agr groups were present: agr group 1 was predominant with 39.5%; agr group 3. agr group 2 and 3 strains carried more toxin-producing genes, and frequently produced more toxin. Sixty-six (26.6%) of the strains were multidrug resistant. All were vancomycin sensitive. Agr group I is more resistant to ciprofloxacin and gentamicin while agr group III is more resistant to erythromycin. Maximum sensitivity was to gentamicin and SXT, and they could be considered drugs of choice for controlling MRSA mediated infections in this region.<br><br>CONCLUSIONS: Biofilm development in MRSA might be an ica dependent and one needs to investigate the involvement of other global regulators, agr and sarA, and their contribution to the biofilm phenotype, as the high rate of biofilm production among the studied strains of S. aureus.},
}
@article {pmid31297368,
year = {2019},
author = {Nichols, D and Pimentel, MB and Borges, FTP and Hyoju, SK and Teymour, F and Hong, SH and Zaborina, OY and Alverdy, JC and Papavasiliou, G},
title = {Sustained Release of Phosphates From Hydrogel Nanoparticles Suppresses Bacterial Collagenase and Biofilm Formation in vitro.},
journal = {Frontiers in bioengineering and biotechnology},
volume = {7},
number = {},
pages = {153},
doi = {10.3389/fbioe.2019.00153},
pmid = {31297368},
issn = {2296-4185},
support = {R01 GM062344/GM/NIGMS NIH HHS/United States ; R21 AI124037/AI/NIAID NIH HHS/United States ; },
abstract = {Intestinal disease or surgical intervention results in local changes in tissue and host-derived factors triggering bacterial virulence. A key phenotype involved in impaired tissue healing is increased bacterial collagenase expression which degrades intestinal collagen. Antibiotic administration is ineffective in addressing this issue as it inadvertently eliminates normal flora while allowing pathogenic bacteria to &quot;bloom&quot; and acquire antibiotic resistance. Compounds that could attenuate collagenase production while allowing commensal bacteria to proliferate normally would offer major advantages without the risk of the emergence of resistance. We have previously shown that intestinal phosphate depletion in the surgically stressed host is a major cue that triggers P. aeruginosa virulence which is suppressed under phosphate abundant conditions. Recent findings indicate that orally administered polyphosphate, hexametaphosphate, (PPi) suppresses collagenase, and biofilm production of P. aeruginosa and S. marcescens in animal models of intestinal injury but does not attenuate E. faecalis induced collagenolytic activity (Hyoju et al., 2017). Systemic administration of phosphates, however, is susceptible to rapid clearance. Given the diversity of collagenase producing bacteria and the variation of phosphate metabolism among microbial species, a combination therapy involving different phosphate compounds may be required to attenuate pathogenic phenotypes. To address these barriers, we present a drug delivery approach for sustained release of phosphates from poly(ethylene) glycol (PEG) hydrogel nanoparticles. The efficacy of monophosphate (Pi)- and PPi-loaded NPs (NP-Pi and NP-PPi, respectively) and a combination treatment (NP-Pi + NP-PPi) in mitigating collagenase and biofilm production of gram-positive and gram-negative pathogens expressing high collagenolytic activity was investigated. NP-PPi was found to significantly decrease collagenase and biofilm production of S. marcescens and P. aeruginosa. Treatment with either NP-Pi or NP-Pi + NP-PPi resulted in more prominent decreases in E. faecalis collagenase compared to NP-PPi alone. The combination treatment was also found to significantly reduce P. aeruginosa collagenase production. Finally, significant attenuation in biofilm dispersal was observed with NP-PPi or NP-Pi + NP-PPi treatment across all test pathogens. These findings suggest that sustained release of different forms of phosphate confers protection against gram-positive and gram-negative pathogens, thereby providing a promising treatment to attenuate expression of tissue-disruptive bacterial phenotypes without eradicating protective flora over the course of intestinal healing.},
}
@article {pmid31297098,
year = {2019},
author = {Friedlander, A and Nir, S and Reches, M and Shemesh, M},
title = {Preventing Biofilm Formation by Dairy-Associated Bacteria Using Peptide-Coated Surfaces.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1405},
doi = {10.3389/fmicb.2019.01405},
pmid = {31297098},
issn = {1664-302X},
abstract = {Biofilm-forming bacteria, which colonize the surfaces of equipment in the dairy industry, may adversely affect the safety and quality of the milk and its products. Despite numerous efforts to combat biofilm formation, there is still no effective technological means to thoroughly solve the biofilm problem in the dairy industry. Here, we introduced peptide-based coating in order to modify the physical properties of the stainless steel surface by affecting its availability for bacterial adhesion. We found that the coated surface displays a notable decrease in the ability of bacterial cells to attach and to subsequently form biofilm by Gram-positive Bacillus licheniformis and Gram-negative Pseudomonas aeruginosa. Furthermore, the coated surface retained its anti-biofilm ability following its exposure to raw milk. Importantly, the modified surface did not affect the milk coagulation process or its nutritious properties and quality. Overall, this anti-biofilm approach may serve as an attractive solution for the dairy industry in its struggle against bacterial contamination.},
}
@article {pmid31297021,
year = {2019},
author = {Al-Yousef, HM and Sheikh, IA},
title = {β-Sitosterol derived compound from onion husks non-polar fraction reduces quorum sensing controlled virulence and biofilm production.},
journal = {Saudi pharmaceutical journal : SPJ : the official publication of the Saudi Pharmaceutical Society},
volume = {27},
number = {5},
pages = {664-672},
doi = {10.1016/j.jsps.2019.04.001},
pmid = {31297021},
issn = {1319-0164},
abstract = {Quorum sensing is an important regulatory factor of P. aeruginosa virulence induction such as BF, motility, formations of proteases, pyocyanin, and some toxins. The aim of the current study is to detect the effect of the pet.ether extract from onion husk and compound drive from it on quorum sensing and virulence formations of P. aeruginosa. Quorum sensing inhibiting effect of the pet.ether extract of onion husk and a compound drive from it, was evaluated by C. violaceum reporter using dilution method as well as an antioxidant by using DPPH. The efficacious of: Quorum sensing inhibiting on pet.ether fraction and compound derived from it, were investigated for their activities toward biofilm and pyocyanin synthesis as well as motility from P. aeruginosa. The pet.ether fraction and compound derived from it of onion husk exhibited potent antimicrobial, antioxidant and Quorum sensing inhibiting effects. The pet.ether fraction and compound derived from it possesses significant reduction on pyocyanin and biofilm induction of P. aeruginosa. Moreover, they significantly inhibited swimming motilities of P. aeruginosa. For the first time, our study showed the medical importance of Allium cepa L. as antimicrobial, antioxidant as well as Quorum sensing inhibiting and virulence suppressors of P. aeruginosa. Thus, these might emphasized on Allium cepa L as a natural source for attenuating toxins of the Pseudomonas.},
}
@article {pmid31295074,
year = {2019},
author = {Carter, MJ and Myntti, MF},
title = {Cost-utility of a biofilm-disrupting gel versus standard of care in chronic wounds: a Markov microsimulation model based on a randomised controlled trial.},
journal = {Journal of wound care},
volume = {28},
number = {Sup7},
pages = {S24-S38},
doi = {10.12968/jowc.2019.28.Sup7.S24},
pmid = {31295074},
issn = {0969-0700},
abstract = {OBJECTIVE: Analyse the cost-effectiveness and treatment outcomes of debridement (standard of care) plus BlastX, a biofilm-disrupting wound gel (group 1) or a triple-antibiotic, maximum-strength ointment (group 2), comparing a subset of patients who had not healed at four weeks using the ointment crossed-over to the biofilm-disrupting gel (group 3).<br><br>METHODS: A series of Markov microsimulation models were built using health states of an unhealed non-infected ulcer, healed ulcer, and infected non-healed ulcer and absorbing states of dead or amputation. All patients started with unhealed non-infected ulcers at cycle 0. Complications and healing rates were based on a randomised controlled trial (RCT). Costs were incurred by patients for procedures at outpatient wound care clinics and hospitals (if complications occurred) and were in the form of Medicare allowable charges. Quality-adjusted life years (QALYs) were computed using literature utility values. Incremental cost-effectiveness ratios (ICERs) were calculated for group 1 versus group 2, and group 3 versus group 2. One-way, multi-way and probabilistic sensitivity analysis (PSA) was conducted.<br><br>RESULTS: After one year, the base case ICER was $8794 per QALY for group 1 versus group 2, and $21,566 per QALY for group 3 versus group 2. Product cost and amputation rates had the most influence in one-way sensitivity analysis. PSA showed that the majority of costs were higher for group 1 but effectiveness values were always higher than for group 2. Average product use of 3.1ml per application represented 9.4% of the total group 1 cost (average $24.52 per application/$822.50 per group 1 patient). The biofilm-disrupting gel group performed substantially better than the current cost-effectiveness benchmarks, $8794 versus $50,000, respectively. Furthermore, when biofilm-disrupting gel treatment was delayed, as in group 3, the ICER outcomes were less substantial but it did remain cost-effective, suggesting the added benefits of immediate use of biofilm-disrupting gel. Also, when product cost assumptions used in the study were halved (Wolcott study usage), the model indicates important reductions in ICER to $966/QALY when comparing group 1 with group 2. It should be noted that product cost can hypothetically be affected not only by direct product purchase costs, but also by application intervals and technique. This suggests additional opportunities exist to optimise these parameters, maximising wound healing efficacy while providing significant cost savings to the payer.<br><br>CONCLUSION: The addition of the biofilm-disrupting gel treatment to standard of care is likely to be cost-effective in the treatment of chronic wounds but when delayed by as little as 9-12 weeks the ICER is still far less than current cost-effectiveness benchmarks. The implication for payers and decision-makers is that biofilm-disrupting gel should be used as a first-line therapy at the first clinic visit rather than waiting as it substantially decreases cost-utility.},
}
@article {pmid31294965,
year = {2019},
author = {Alizadeh, S and Abdul Rahim, A and Guo, B and Hawari, J and Ghoshal, S and Comeau, Y},
title = {Impacts of Continuous Inflow of Low Concentrations of Silver Nanoparticles on Biological Performance and Microbial Communities of Aerobic Heterotrophic Wastewater Biofilm.},
journal = {Environmental science &amp; technology},
volume = {53},
number = {15},
pages = {9148-9159},
doi = {10.1021/acs.est.9b01214},
pmid = {31294965},
issn = {1520-5851},
abstract = {Attached-growth wastewater processes are currently used in water resource recovery facilities (WRRFs) for required upgrades due to an increase in influent loading or to reach more stringent discharge criteria. Yet, the distribution and long-term inhibitory effects of silver nanoparticles (AgNPs) in attached-growth biological wastewater processes and their impact on involved microbial communities are poorly understood at relevant, low concentrations. Retention, distribution, and long-term inhibitory effect of polyvinylpyrrolidone (PVP)-coated AgNPs were evaluated in bench-scale moving bed biofilm reactors (MBBRs), achieving soluble organic matter removal, over a 64 day exposure to nominal concentrations of 10 and 100 μg/L. Distributions of continuously added AgNPs were characterized in the influent, bioreactor, and effluent of MBBRs using single particle inductively coupled plasma mass spectroscopy (spICP-MS). Aerobic heterotrophic biofilms in MBBRs demonstrated limited retention capacity for AgNPs over long-term exposure, with release of AgNPs, and Ag-rich biofilm sloughed from the carriers. Continuous exposure to both influent AgNP concentrations significantly decreased soluble chemical oxygen demand (SCOD) removal efficiency (11% to 31%) and reduced biofilm viability (8% to 30%). Specific activities of both intracellular dehydrogenase (DHA) and extracellular α-glucosidase (α-Glu) and protease (PRO) enzymes were significantly inhibited (8% to 39%) with an observed NP dose-dependent intracellular reactive oxygen species (ROS) production and shift in biofilm microbial community composition by day 64. Our results indicated that long-term exposure to AgNPs in biofilm processes at environmentally relevant concentrations can impact the treatment process stability and the quality of the discharged effluent.},
}
@article {pmid31294223,
year = {2018},
author = {Xaxiri, NA and Nikouli, E and Berillis, P and Kormas, KA},
title = {Bacterial biofilm development during experimental degradation of Melicertus kerathurus exoskeleton in seawater.},
journal = {AIMS microbiology},
volume = {4},
number = {3},
pages = {397-412},
doi = {10.3934/microbiol.2018.3.397},
pmid = {31294223},
issn = {2471-1888},
abstract = {Chitinolytic bacteria are widespread in marine and terrestrial environment, and this is rather a reflection of their principle growth substrate's ubiquity, chitin, in our planet. In this paper, we investigated the development of naturally occurring bacterial biofilms on the exoskeleton of the shrimp Melicertus kerathurus during its degradation in sea water. During a 12-day experiment with exoskeleton fragments in batch cultures containing only sea water as the growth medium at 18 °C in darkness, we analysed the formation and succession of biofilms by scanning electron microscopy and 16S rRNA gene diversity by next generation sequencing. Bacteria belonging to the γ- and α-Proteobacteria and Bacteroidetes showed marked (less or more than 10%) changes in their relative abundance from the beginning of the experiment. These bacterial taxa related to known chitinolytic bacteria were the Pseudolateromonas porphyrae, Halomonasaquamarina, Reinekea aestuarii, Colwellia asteriadis and Vibrio crassostreae. These bacteria could be considered as appropriate candidates for the degradation of chitinous crustacean waste from the seafood industry as they dominated in the biofilms developed on the shrimp's exoskeleton in natural sea water with no added substrates and the degradation of the shrimp exoskeleton was also evidenced.},
}
@article {pmid31294028,
year = {2019},
author = {Coelho, C and Gougeon, RD and Perepelkine, L and Alexandre, H and Guzzo, J and Weidmann, S},
title = {Chemical Transfers Occurring Through Oenococcus oeni Biofilm in Different Enological Conditions.},
journal = {Frontiers in nutrition},
volume = {6},
number = {},
pages = {95},
doi = {10.3389/fnut.2019.00095},
pmid = {31294028},
issn = {2296-861X},
abstract = {Chardonnay wine malolactic fermentations were carried out to evaluate the chemical transfers occurring at the wood/wine interface in the presence of two different bacterial lifestyles. To do this, Oenococcus oeni was inoculated into must and wine in its planktonic and biofilm lifestyles, whether adhering or not to oak chips, leading to three distinct enological conditions: (i) post-alcoholic fermentation inoculation in wine in the absence of oak chips, (ii) post-alcoholic fermentation inoculation in wine in the presence of oak chips, and (iii) co-inoculation of both Saccharomyces cerevisiae and O. oeni directly in Chardonnay musts in the presence of oak chips. Classical microbiological and physico-chemical parameters analyzed during the fermentation processes confirmed that alcoholic fermentation was completed identically regardless of the enological conditions, and that once O. oeni had acquired a biofilm lifestyle in the presence or absence of oak, malolactic fermentation occurred faster and with better reproducibility compared to planktonic lifestyles. Analyses of volatile components (higher alcohols and wood aromas) and non-volatile components (Chardonnay grape polyphenols) carried out in the resulting wines revealed chemical differences, particularly when bacterial biofilms were present at the wood interface. This study revealed the non-specific trapping activity of biofilm networks in the presence of wood and grape compounds regardless of the enological conditions. Changes of concentrations in higher alcohols reflected the fermentation bioactivity of bacterial biofilms on wood surfaces. These chemical transfers were statistically validated by an untargeted approach using Excitation Emission Matrices of Fluorescence combined with multivariate analysis to discriminate innovative enological practices during winemaking and to provide winemakers with an optical tool for validating the biological and chemical differentiations occurring in wine that result from their decisions.},
}
@article {pmid31293539,
year = {2019},
author = {Schiffer, C and Hilgarth, M and Ehrmann, M and Vogel, RF},
title = {Bap and Cell Surface Hydrophobicity Are Important Factors in Staphylococcus xylosus Biofilm Formation.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1387},
doi = {10.3389/fmicb.2019.01387},
pmid = {31293539},
issn = {1664-302X},
abstract = {Staphylococcus (S.) xylosus is a coagulase-negative Staphylococcus species naturally present in food of animal origin with a previously described potential for biofilm formation. In this study we characterized biofilm formation of five selected strains isolated from raw fermented dry sausages, upon different growth conditions. Four strains exhibited a biofilm positive phenotype with strain-dependent intensities. Biofilm formation of S. xylosus was influenced by the addition of glucose, sodium chloride and lactate to the growth medium, respectively. It was further dependent on strain-specific cell surface properties. Three strains exhibited hydrophobic and two hydrophilic cell surface properties. The biofilm positive hydrophilic strain TMW 2.1523 adhered significantly better to hydrophilic than to hydrophobic supports, whereas the differences in adherence to hydrophobic versus hydrophilic supports were not as distinct for the hydrophobic strains TMW 2.1023, TMW 2.1323, and TMW 2.1521. Comparative genomics enabled prediction of functional biofilm-related genes and link these to phenotypic variations. While a wide range of biofilm associated factors/genes previously described for S. aureus and S. epidermidis were absent in the genomes of the five strains analyzed, they all possess the gene encoding biofilm associated protein Bap. The only biofilm negative strain TMW 2.1602 showed a mutation in the bap sequence. This study demonstrates that Bap and surface hydrophobicity are important factors in S. xylosus biofilm formation with potential impact on the assertiveness of a starter strain against autochthonous staphylococci by competitive exclusion during raw sausage fermentation.},
}
@article {pmid31293528,
year = {2019},
author = {Ranjith, K and Ramchiary, J and Prakash, JSS and Arunasri, K and Sharma, S and Shivaji, S},
title = {Gene Targets in Ocular Pathogenic Escherichia coli for Mitigation of Biofilm Formation to Overcome Antibiotic Resistance.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1308},
doi = {10.3389/fmicb.2019.01308},
pmid = {31293528},
issn = {1664-302X},
abstract = {The present work is an attempt to establish the functionality of genes involved in biofilm formation and antibiotic resistance in an ocular strain of Escherichia coli (L-1216/2010) which was isolated and characterized from the Vitreous fluid of a patient with Endophthalmitis. For this purpose, seven separate gene-specific knockout mutants were generated by homologous recombination in ocular E. coli. The genes that were mutated included three transmembrane genes ytfR (ABC transporter ATP-binding protein), mdtO (multidrug efflux system) and tolA (inner membrane protein), ryfA coding for non-coding RNA and three metabolic genes mhpA (3-3-hydroxyphenylpropionate 1,2-dioxygenase), mhpB (2,3-di hydroxyphenylpropionate 1,2-dioxygenase), and bdcR (regulatory gene of bdcA). Mutants were validated by sequencing and Reverse transcription-PCR and monitored for biofilm formation by XTT method and confocal microscopy. The antibiotic susceptibility of the mutants was also ascertained. The results indicated that biofilm formation was inhibited in five mutants (ΔbdcR, ΔmhpA, ΔmhpB, ΔryfA, and ΔtolA) and the thickness of biofilm reduced from 17.2 μm in the wildtype to 1.5 to 4.8 μm in the mutants. Mutants ΔytfR and ΔmdtO retained the potential to form biofilm. Complementation of the mutants with the wild type gene restored biofilm formation potential in all mutants except in ΔmhpB. The 5 mutants which lost their ability to form biofilm (ΔbdcR, ΔmhpA, ΔmhpB, ΔtolA, and ΔryfA) did not exhibit any change in their susceptibility to Ceftazidime, Cefuroxime, Ciprofloxacin, Gentamicin, Cefotaxime, Sulfamethoxazole, Imipenem, Erythromycin, and Streptomycin in the planktonic phase compared to wild type ocular E. coli. But ΔmdtO was the only mutant with altered MIC to Sulfamethoxazole, Imipenem, Erythromycin, and Streptomycin both in the planktonic and biofilm phase. This is the first report demonstrating the involvement of the metabolic genes mhpA and mhpB and bdcR (regulatory gene of bdcA) in biofilm formation in ocular E. coli. In addition we provide evidence that tolA and ryfA are required for biofilm formation while ytfR and mdtO are not required. Mitigation of biofilm formation to overcome antibiotic resistance could be achieved by targeting the genes bdcR, mhpA, mhpB, ryfA, and tolA.},
}
@article {pmid31293526,
year = {2019},
author = {Gannesen, AV and Zdorovenko, EL and Botchkova, EA and Hardouin, J and Massier, S and Kopitsyn, DS and Gorbachevskii, MV and Kadykova, AA and Shashkov, AS and Zhurina, MV and Netrusov, AI and Knirel, YA and Plakunov, VK and Feuilloley, MGJ},
title = {Composition of the Biofilm Matrix of Cutibacterium acnes Acneic Strain RT5.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1284},
doi = {10.3389/fmicb.2019.01284},
pmid = {31293526},
issn = {1664-302X},
abstract = {In skin, Cutibacterium acnes (former Propionibacterium acnes) can behave as an opportunistic pathogen, depending on the strain and environmental conditions. Acneic strains of C. acnes form biofilms inside skin-gland hollows, inducing inflammation and skin disorders. The essential exogenous products of C. acnes accumulate in the extracellular matrix of the biofilm, conferring essential bacterial functions to this structure. However, little is known about the actual composition of the biofilm matrix of C. acnes. Here, we developed a new technique for the extraction of the biofilm matrix of Gram-positive bacteria without the use of chemical or enzymatic digestion, known to be a source of artifacts. Our method is based on the physical separation of the cells and matrix of sonicated biofilms by ultracentrifugation through a CsCl gradient. Biofilms were grown on the surface of cellulose acetate filters, and the biomass was collected without contamination by the growth medium. The biofilm matrix of the acneic C. acnes RT5 strain appears to consist mainly of polysaccharides. The following is the ratio of the main matrix components: 62.6% polysaccharides, 9.6% proteins, 4.0% DNA, and 23.8% other compounds (porphyrins precursors and other). The chemical structure of the major polysaccharide was determined using a nuclear magnetic resonance technique, the formula being →6)-α-D-Galp-(1→4)-β-D-ManpNAc3NAcA-(1→6)-α-D-Glcp-(1→4)-β-D-ManpNAc3NAcA-(1→3)-β-GalpNAc-(1→. We detected 447 proteins in the matrix, of which the most abundant were the chaperonin GroL, the elongation factors EF-Tu and EF-G, several enzymes of glycolysis, and proteins of unknown function. The matrix also contained more than 20 hydrolases of various substrata, pathogenicity factors, and many intracellular proteins and enzymes. We also performed surface-enhanced Raman spectroscopy analysis of the C. acnes RT5 matrix for the first time, providing the surface-enhanced Raman scattering (SERS) profiles of the C. acnes RT5 biofilm matrix and biofilm biomass. The difference between the matrix and biofilm biomass spectra showed successful matrix extraction rather than simply the presence of cell debris after sonication. These data show the complexity of the biofilm matrix composition and should be essential for the development of new anti-C. acnes biofilms and potential antibiofilm drugs.},
}
@article {pmid31292867,
year = {2019},
author = {Calapez, AR and Elias, CL and Almeida, SFP and Brito, AG and Feio, MJ},
title = {Sewage contamination under water scarcity effects on stream biota: biofilm, grazers, and their interaction.},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11356-019-05876-7},
pmid = {31292867},
issn = {1614-7499},
support = {PD\BD\52510\2014//Fundação para a Ciência e a Tecnologia/ ; UID/MAR/04292/2013//Fundação para a Ciência e a Tecnologia/ ; UID/GEO/04035/2013//Fundação para a Ciência e a Tecnologia/ ; },
abstract = {One of the most common anthropogenic impacts on river ecosystems is the effluent discharge from wastewater treatment plants. The effects of this contamination on stream biota may be intensified in Mediterranean climate regions, which comprise a drought period that leads to flow reduction, and ultimately to stagnant pools. To assess individual and combined effects of flow stagnation and sewage contamination, biofilm and gastropod grazers were used in a 5-week experiment with artificial channels to test two flow velocity treatments (stagnant flow/basal flow) and two levels of organic contamination using artificial sewage (no sewage input/sewage input). Stressors' effects were determined on biofilm total biomass and chlorophyll (Chl) content, on oxygen consumption and growth rate of the grazers (Theodoxus fluviatilis), and on the interaction grazer-biofilm given by grazer's feeding activity (i.e., biofilm consumption rate). The single effect of sewage induced an increase in biofilm biomass and Chl-a content, simultaneously increasing both grazers' oxygen consumption and their feeding activity. Diatoms showed a higher sensitivity to flow stagnation, resulting in a lower content of Chl-c. Combined stressors interacted antagonistically for biofilm total biomass, Chl-b contents, and grazers's feeding rate. The effect of sewage increasing biofilm biomass and grazing activity was reduced by the presence of flow stagnation (antagonist factor). Our findings suggest that sewage contamination has a direct effect on the functional response of primary producers and an indirect effect on primary consumers, and this effect is influenced by water flow stagnation.},
}
@article {pmid31291096,
year = {2019},
author = {Wang, M and Shi, J and Mao, H and Sun, Z and Guo, S and Guo, J and Yan, F},
title = {Fluorescent Imidazolium-Type Poly(ionic liquid)s for Bacterial Imaging and Biofilm Inhibition.},
journal = {Biomacromolecules},
volume = {20},
number = {8},
pages = {3161-3170},
doi = {10.1021/acs.biomac.9b00741},
pmid = {31291096},
issn = {1526-4602},
abstract = {Fluorescent imidazolium-type poly(ionic liquid)s (PIL)s were synthesized by anion exchange of bromide (Br-) in poly(3-butyl-1-vinylimidazolium bromide) (PIL-Br) with a fluorescent anion, namely, 3-(4-(1,2,2-triphenylvinyl)phenoxy)propane-1-sulfonate (TPESO3-). Such an anion exchange provided antibacterial PILs with aggregation-induced emission (AIE) properties that simultaneously kill and image bacteria. These fluorescence and antibacterial properties could be regulated by controlling the Br-/TPESO3- ratio. The fluorescence intensity increases as this ratio increases, while the antibacterial property exhibits an opposite trend. Moreover, the AIE-type PILs are useful for fluorescently imaging dead bacteria (macroscopically and microscopically) and could effectively inhibit biofilm growth. This study provided a convenient method to obtain fluorescent PILs with adjustable antibacterial and imaging properties.},
}
@article {pmid31290732,
year = {2019},
author = {Süß, M and De Visscher, A},
title = {Effect of diffusion limitation and substrate inhibition on steady states of a biofilm reactor treating a single pollutant.},
journal = {Journal of the Air &amp; Waste Management Association (1995)},
volume = {69},
number = {9},
pages = {1107-1115},
doi = {10.1080/10962247.2019.1631904},
pmid = {31290732},
issn = {2162-2906},
abstract = {The occurrence of multiple steady states in a toluene biodegrading, diffusion-limited biofilm under aerobic conditions was investigated by computer models: one steady-state, and one nonsteady-state. Two stable and one unstable intermediate steady-state were identified in a narrow set of combinations of parameters values. The nonsteady-state model predicts conditions that evolve to a steady state that is within 0.02-1% of the solution of the steady-state model, depending on the number of grid points used, confirming the algorithms are valid. Multiple steady states occur if, (1) a biofilm is exposed to a constant gas-phase pollution concentration, which exceeds or undershoots a certain threshold, (2) in a narrow range of parameter values and (3) provided that the pollutant degradation follows Haldane kinetics. Such a biofilm displays half-saturation (i.e., Michaelis-Menten)-like apparent (&quot;falsified&quot;) kinetics from a concentration range starting at zero up to the occurrence of a second steady state. Multiple steady states and falsified kinetics can negatively affect a biofilter and the experimental determination of kinetic parameters, respectively. Implications: The occurrence of multiple steady states in a VOC treating biofilm, shows the significant impact of degradation kinetics and diffusion limitation on the biofilm behavior. Moreover, the implied possible sudden drop of removal efficiency of a biofilter, based on the occurrence of multiple steady states lead to possible bottle-necks in biofilter application and operation.},
}
@article {pmid31289312,
year = {2019},
author = {Lim, ES and Koo, OK and Kim, MJ and Kim, JS},
title = {Bio-enzymes for inhibition and elimination of Escherichia coli O157:H7 biofilm and their synergistic effect with sodium hypochlorite.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {9920},
doi = {10.1038/s41598-019-46363-w},
pmid = {31289312},
issn = {2045-2322},
abstract = {Escherichia coli O157:H7 is one of the most important pathogens worldwide. In this study, three different kinds of enzymes, DNase I, proteinase K and cellulase were evaluated for inhibitory or degrading activity against E. coli O157:H7 biofilm by targeting extracellular DNA, proteins, and cellulose, respectively. The cell number of biofilms formed under proteinase K resulted in a 2.43 log CFU/cm2 reduction with an additional synergistic 3.72 log CFU/cm2 reduction after NaClO post-treatment, while no significant reduction occurred with NaClO treatment alone. It suggests that protein degradation could be a good way to control the biofilm effectively. In preformed biofilms, all enzymes showed a significant reduction of 16.4-36.7% in biofilm matrix in 10-fold diluted media (p < 0.05). The sequential treatment with proteinase K, cellulase, and NaClO showed a significantly higher synergistic inactivation of 2.83 log CFU/cm2 compared to 1.58 log CFU/cm2 in the sequence of cellulase, proteinase K, and NaClO (p < 0.05). It suggests that the sequence of multiple enzymes can make a significant difference in the susceptibility of biofilms to NaClO. This study indicates that the combination of extracellular polymeric substance-degrading enzymes with NaClO could be useful for the efficient control of E. coli O157:H7 biofilms.},
}
@article {pmid31288972,
year = {2019},
author = {Tsai, MH and Liang, YH and Chen, CL and Chiu, CH},
title = {Characterization of Salmonella resistance to bile during biofilm formation.},
journal = {Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jmii.2019.06.003},
pmid = {31288972},
issn = {1995-9133},
abstract = {BACKGROUND: Non-typhoid Salmonella infection may present as acute gastroenteritis or chronic infection, primarily in the bile-rich gallbladder. Biofilm formation is a mechanism of bile resistance in Salmonella. Our aim was to determine how Salmonella utilizes bile as a signal, and to study the relevance of the interaction between the PhoP-PhoQ two-component system and cyclic diguanosine monophosphate (c-di-GMP) signaling to biofilm formation.<br><br>METHODS: Two-dimensional (2-D) gel electrophoresis was used to identify genes required for Salmonella biofilm formation in bile. Quantitative real-time PCR (qRT-PCR) was used to clarify the role of the PhoP-PhoQ two-component system and its interaction with genes involved in the c-di-GMP network during biofilm formation.<br><br>RESULTS: Our result revealed that Salmonella mutants with incomplete outer membrane (△ompA), defective flagella (△flgE), or incomplete PhoP-PhoQ two-component system (△phoP), were unable to develop complete biofilms in the presence of bile. Moreover, PhoP-PhoQ two-component system-related Salmonella mutants (△phoP, △phoQ, △phoP△phoQ) had lower expression of c-di-GMP related genes (csgD, adrA) than the wild-type Salmonella strain had in the bile environment.<br><br>CONCLUSION: Salmonella may sense and respond to bile through the PhoP-PhoQ two-component system during biofilm formation. Furthermore, the PhoP-PhoQ two-component system might activate regulators of the c-di-GMP signaling network.},
}
@article {pmid31288325,
year = {2019},
author = {Wu, F and Li, MC and Sun, CC and Liu, Y and Wu, LG},
title = {[Influence of environmental factors on the two-species biofilm formed by Streptococcus oligofermentans and Streptococcus mutans].},
journal = {Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology},
volume = {54},
number = {7},
pages = {456-462},
doi = {10.3760/cma.j.issn.1002-0098.2019.07.005},
pmid = {31288325},
issn = {1002-0098},
abstract = {Objective: To study the influence of environmental factors on the two-species biofilm formed by the combinations of Streptococcus oligofermentans (So) with Streptococcus mutans (Sm) and Streptococcus sanguinis (Ss) with Sm so as to evaluate the role of So in maintaining the microecological balance of the oral cavity. Methods: Single-and two-species biofilms were grown on saliva-coated surfaces (glass tube and 96-well plate). Colony-counting method and safranin staining method were used to measure the biofilms formed under various oxygen conditions (aerobic and anaerobic), sucrose conditions (0%, 1% and 5% sucrose concentrations) and pH conditions (5.5, 6.0, 6.5, 7.0, 7.5 and 8.0). Results: Comparing the numbers of Sm in two co-cultures under various conditions, Sm counts in So+Sm group [(7.70±2.46)×10(8) CFU/ml] were significantly lower than those in Ss+Sm group [(9.00±1.13)×10(8) CFU/ml] in aerobic environment (P<0.05). Sm counts in So+Sm group [(2.80±0.52)×10(8) CFU/ml] were also significantly lower than those in the Ss+Sm group [(4.00±1.25)×10(8) CFU/ml] in anaerobic environment (P<0.05). The Sm counts in So+Sm group [(8.90±0.82)×10(8) CFU/ml] were significantly higher than those in Ss+Sm group [(7.50±1.73)×10(8) CFU/ml] in 0% sucrose environment (P<0.05). The Sm counts in So+Sm group [(5.70±2.94)×10(8) CFU/ml] were significantly lower than those in Ss+Sm group [(10.30±3.21) ×10(8) CFU/ml] in 1% sucrose environment (P<0.05). The Sm counts in So+Sm group [(6.10±1.71)×10(8) CFU/ml] were also significantly lower than those in Ss+Sm group [(7.40±1.20)×10(8) CFU/ml] in 5% sucrose environment (P<0.05). The Sm counts in So+Sm group [(3.50±1.50)×10(8) CFU/ml] were significantly lower than those in Ss+Sm group [(10.70±2.80)×10(8) CFU/ml] in pH7.0 environment (P<0.05). Comparing the formation of biofilm after 24 h cultivation, the Sm counts in So+Sm group were significantly lower than those in Ss+Sm group both in aerobic and anaerobic environments (P<0.05). The Sm counts in So+Sm group were significantly higher than those in Ss+Sm group in 0% sucrose environment (P<0.05). The Sm counts in So+Sm group were significantly lower than those in Ss+Sm group in 1% and 5% sucrose and pH 7.0 environments (P<0.05). Both So and Ss had no inhibitory effect on Sm in pH5.5 and pH8.0 environments. Conclusions: In the in vitro two-species co-culture systems, So showed stronger inhibitory effects than Ss on Sm and its inhibitory ability might influenced by various environmental factors.},
}
@article {pmid31287946,
year = {2019},
author = {Xiang, Z and Li, Z and Ren, Z and Zeng, J and Peng, X and Li, Y and Li, J},
title = {EzrA, a cell shape regulator contributing to biofilm formation and competitiveness in Streptococcus mutans.},
journal = {Molecular oral microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/omi.12264},
pmid = {31287946},
issn = {2041-1014},
support = {//National Key Technologies R&amp;D Program of the Twelve Five-year Plan/ ; 2012BAI07B03//Ministry of Science and Technology of China/ ; 81371135//National Natural Science Foundation of China/ ; 31870065//National Natural Science Foundation of China/ ; },
abstract = {Bacterial cell division is initiated by tubulin homologue FtsZ that assembles into a ring structure at mid-cell to facilitate cytokinesis. EzrA has been identified to be implicated in FtsZ-ring dynamics and cell wall biosynthesis during cell division of Bacillus subtilis and Staphylococcus aureus, the model rod and cocci. However, its role in pathogenic streptococci remains largely unknown. Here, the role of EzrA was investigated in Streptococcus mutans, the primary etiological agent of human dental caries, by constructing an ezrA in-frame deletion mutant. Our data showed that the ezrA mutant was slow-growing with a shortened length and extended width round cell shape compared to the wild type, indicating a delay in cell division with abnormalities of peptidoglycan biosynthesis. Additionally, FtsZ irregularly localized in dividing ezrA mutant cells forming angled division planes, potentially contributing to an aberrant cell shape. Furthermore, investigation using single-species cariogenic biofilm model revealed that deletion of ezrA resulted in defective biofilm formation with less extracellular polysaccharides and altered three-dimensional biofilm architecture. Unexpectedly, in a dual-species ecological model, the ezrA mutant exhibited substantially lower tolerance for H2 O2 and reduced competitiveness against one commensal species, Streptococcus sanguinis. Taken together, these results demonstrate that EzrA plays a key role in regulating cell division and maintaining a normal morphology in S. mutans and is required for its robust biofilm formation/interspecies competition. Therefore, EzrA protein represents a potential therapeutic target in the development of drugs controlling dental caries and other biofilm-related diseases.},
}
@article {pmid31287831,
year = {2019},
author = {Ryser, S and Tenorio, E and Estellés, A and Kauvar, LM},
title = {Human antibody repertoire frequently includes antibodies to a bacterial biofilm associated protein.},
journal = {PloS one},
volume = {14},
number = {7},
pages = {e0219256},
doi = {10.1371/journal.pone.0219256},
pmid = {31287831},
issn = {1932-6203},
support = {SB1 AI120425/AI/NIAID NIH HHS/United States ; },
abstract = {We have previously described a native human monoclonal antibody, TRL1068, that disrupts bacterial biofilms by extracting from the biofilm matrix key scaffolding proteins in the DNABII family, which are present in both gram positive and gram negative bacterial species. The antibiotic resistant sessile bacteria released from the biofilm then revert to the antibiotic sensitive planktonic state. Qualitative resensitization to antibiotics has been demonstrated in three rodent models of acute infections. We report here the surprising discovery that antibodies against the target family were found in all twenty healthy humans surveyed, albeit at a low level requiring a sensitive single B-cell assay for detection. We have cloned 21 such antibodies. Aside from TRL1068, only one (TRL1330) has all the biochemical properties believed necessary for pharmacological efficacy (broad spectrum epitope specificity and high affinity). We suggest that the other anti-DNABII antibodies, while not necessarily curative, reflect an immune response at some point in the donor's history to these components of biofilms. Such an immune response could reflect exposure to bacterial reservoirs that have been previously described in chronic non-healing wounds, periodontal disease, chronic obstructive pulmonary disease, colorectal cancer, rheumatoid arthritis, and atherosclerotic artery explants. The detection of anti-DNABII antibodies in all twenty surveyed donors with no active infection suggests that bacterial biofilm reservoirs may be present periodically in most healthy individuals. Biofilms routinely shed bacteria, creating a continuous low level inflammatory stimulus. Since chronic subclinical inflammation is thought to contribute to most aging-related diseases, suppression of bacterial biofilm has potential value in delaying age-related pathology.},
}
@article {pmid31286367,
year = {2019},
author = {Dong, QY and Wang, Z and Shi, LD and Lai, CY and Zhao, HP},
title = {Anaerobic methane oxidation coupled to chromate reduction in a methane-based membrane biofilm batch reactor.},
journal = {Environmental science and pollution research international},
volume = {26},
number = {25},
pages = {26286-26292},
doi = {10.1007/s11356-019-05709-7},
pmid = {31286367},
issn = {1614-7499},
support = {21577123, 51878596//National Natural Science Foundation of China/ ; LR17B070001//Natural Science Funds for Distinguished Young Scholar of Zhejiang Province/ ; },
abstract = {Chromate can be reduced by methanotrophs in a membrane biofilm reactor (MBfR). In this study, we cultivated a Cr(VI)-reducing biofilm in a methane (CH4)-based membrane biofilm batch reactor (MBBR) under anaerobic conditions. The Cr(VI) reduction rate increased to 0.28 mg/L day when the chromate concentration was ≤ 2.2 mg/L but declined sharply to 0.01 mg/L day when the Cr(VI) concentration increased to 6 mg/L. Isotope tracing experiments showed that part of the 13C-labeled CH4 was transformed to 13CO2, suggesting that the biofilm may reduce Cr(VI) by anaerobic methane oxidation (AnMO). Microbial community analysis showed that a methanogen, i.e., Methanobacterium, dominated in the biofilm, suggesting that this genus is probably capable of carrying out AnMO. The abundance of Methylomonas, an aerobic methanotroph, decreased significantly, while Meiothermus, a potential chromate-reducing bacterium, was enriched in the biofilm. Overall, the results showed that the anaerobic environment inhibited the activity of aerobic methanotrophs while promoting AnMO bacterial enrichment, and high Cr(VI) loading reduced Cr(VI) flux by inhibiting the methane oxidation process.},
}
@article {pmid31286118,
year = {2019},
author = {Menini, M and Setti, P and Dellepiane, E and Zunino, P and Pera, P and Pesce, P},
title = {Comparison of biofilm removal using glycine air polishing versus sodium bicarbonate air polishing or hand instrumentation on full-arch fixed implant rehabilitations: a split-mouth study.},
journal = {Quintessence international (Berlin, Germany : 1985)},
volume = {50},
number = {9},
pages = {722-730},
doi = {10.3290/j.qi.a42704},
pmid = {31286118},
issn = {1936-7163},
abstract = {OBJECTIVES: To compare the cleaning efficacy of glycine air polishing against two different professional oral hygiene techniques on implants supporting full-arch fixed prostheses.<br><br>METHOD AND MATERIALS: Thirty patients with a total of 32 implant fixed full-arch rehabilitations in the maxilla and/or mandible (134 implants) were included. After the removal of the screw-retained prostheses, baseline peri-implant spontaneous bleeding (SB), Plaque Index (PI), probing depth (PD), and bleeding on probing (BOP) were recorded (T0). Three oral hygiene treatments were assigned randomly following a split-mouth method: all the patients received glycine air polishing (G) in one side of the arch (n = 32), and sodium bicarbonate air polishing (B) (n = 16) or manual scaling with carbon-fiber curette (C) (n = 16) was performed in the opposite side. After the hygiene procedures, PI and SB were recorded and patient's comfort degree towards the three techniques was analyzed by questionnaires using a rating scale from 1 to 5 (T1).<br><br>RESULTS: PI reduction was significantly higher for G (T0, 2.88 ± 1.37; T1, 0.04 ± 0.21) and B (T0, 3.13 ± 1.34; T1, 0.0 ± 0.0) as compared with C (T0, 2.15 ± 1.46; T1, 0.44 ± 0.7) (P < .001). B reported the highest mean value of SB (T0, 0.0 ± 0.0; T1, 3.42 ± 0.75) compared with G (T0, 0.05 ± 0.21; T1, 1.60 ± 1.05) and C (T0, 0.07 ± 0.24; T1, 0.73 ± 0.91) (P < .001). A significant difference in comfort mean score was found between G (4.8 ± 0.5) and B (3.5 ± 1.7) (P = .014), no difference between G and C (4.7 ± 0.7) (P = .38).<br><br>CONCLUSION: Professional oral hygiene on implants using glycine air polishing showed high levels of both cleaning efficacy and patients' acceptance.},
}
@article {pmid31284975,
year = {2019},
author = {Merino, L and Trejo, FM and De Antoni, G and Golowczyc, MA},
title = {Lactobacillus strains inhibit biofilm formation of Salmonella sp. isolates from poultry.},
journal = {Food research international (Ottawa, Ont.)},
volume = {123},
number = {},
pages = {258-265},
doi = {10.1016/j.foodres.2019.04.067},
pmid = {31284975},
issn = {1873-7145},
abstract = {Lactic acid bacteria (LAB) exert a strong antagonistic activity against many microorganisms including food spoilage organisms and may be used as an alternative to control biofilm formation of pathogens in food industries. The objective of this work was to investigate the ability of fifteen Salmonella strains isolated from poultry environment to form biofilms on different surfaces. In addition, the effect of Lactobacillus kefiri strains 8321 and 83113 and Lactobacillus plantarum 83114 and their surface proteins on biofilm development of Salmonella Enteritidis 115 was studied. The relationship between surface properties of bacteria (hydrophobicity, autoaggregation and coaggregation with lactobacilli) and biofilm formation was also investigated. Most of Salmonella strains were hydrophilic and five strains were moderately hydrophobic. In general, Salmonella strains showed high aggregation abilities (27-54%). S. Enteritidis 106 and S. Typhimurium 102 and 108 showed the highest percentages of autoaggregation. All Salmonella strains tested showed aggregation abilities with the three lactobacilli studied, but the percentage of coaggregation proved to be strain-specific. When comparing stainless steel, glass and polystyrene surfaces, higher levels of biofilm formation occurred on polystyrene plate than on glass surfaces or stainless steel. S. Enteritidis 115 exhibited the greatest attachment to polyestyrene surface. The preincubation or coincubation with the three lactobacilli strains significantly reduced (about 1 log CFU/ml of reduction) the ability of S. Enteritidis 115 to form biofilm compared to the control without lactobacilli. These results were confirmed by confocal microscopy. In the same way, when surface proteins extracted from lactobacilli strains were preincubated or coincubated with S. Enteritidis 115, biofilm formation of this strain was significantly decreased compared to the control. The results obtained showed that these Lactobacillus strains and their surface proteins can be used as alternatives for control of biofilm formation by Salmonella in the poultry industry.},
}
@article {pmid31284940,
year = {2019},
author = {Rajkumari, J and Borkotoky, S and Reddy, D and Mohanty, SK and Kumavath, R and Murali, A and Suchiang, K and Busi, S},
title = {Anti-quorum sensing and anti-biofilm activity of 5-hydroxymethylfurfural against Pseudomonas aeruginosa PAO1: Insights from in vitro, in vivo and in silico studies.},
journal = {Microbiological research},
volume = {226},
number = {},
pages = {19-26},
doi = {10.1016/j.micres.2019.05.001},
pmid = {31284940},
issn = {1618-0623},
mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins ; Biofilms/*drug effects ; Caenorhabditis elegans ; Computer Simulation ; Disease Models, Animal ; Furaldehyde/*analogs &amp; derivatives/pharmacology ; Gene Expression Regulation, Bacterial/drug effects ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Pseudomonas aeruginosa/*drug effects/*pathogenicity ; Quorum Sensing/*drug effects/genetics ; Survival Rate ; Trans-Activators ; Virulence/drug effects ; Virulence Factors ; },
abstract = {Pseudomonas aeruginosa is one of the most common pathogens associated with nosocomial infections and a great concern to immunocompromised individuals especially in the cases of cystic fibrosis, AIDS and burn wounds. The pathogenicity of P. aeruginosa is largely directed by the quorum sensing (QS) system. Hence, QS may be considered an important therapeutic target to combat P. aeruginosa infections. The anti-quorum sensing and anti-biofilm efficacy of aromatic aldehyde, 5-hydroxymethylfurfural (5-HMF) against P. aeruginosa PAO1 were assessed. At the sub-inhibitory concentration, 5-HMF suppressed the production of QS-controlled virulence phenotypes and biofilm formation in P. aeruginosa. It was also able to significantly enhance the survival rate of C. elegans infected with P. aeruginosa. The in silico studies revealed that 5-HMF could serve as a competitive inhibitor for the auto-inducer molecules as it exhibited a strong affinity for the regulatory proteins of the QS-circuits i.e. LasR and RhlR. In addition, a significant down-regulation in the expression of QS-related genes was observed suggesting the ability of 5-HMF in mitigating the pathogenicity of P. aeruginosa.},
}
@article {pmid31284905,
year = {2019},
author = {Li, L and Yan, G and Wang, H and Chu, Z and Li, Z and Ling, Y and Wu, T},
title = {Denitrification and microbial community in MBBR using A. donax as carbon source and biofilm carriers for reverse osmosis concentrate treatment.},
journal = {Journal of environmental sciences (China)},
volume = {84},
number = {},
pages = {133-143},
doi = {10.1016/j.jes.2019.04.030},
pmid = {31284905},
issn = {1001-0742},
mesh = {Bioreactors/*microbiology ; *Denitrification ; *Microbial Consortia ; Nitrogen/*isolation &amp; purification ; Poaceae/*chemistry/microbiology ; Water Purification ; },
abstract = {In this study, raw Arundo donax (A. donax) pieces were applied as carbon source and biofilm carriers for denitrification in a lab-scale moving bed biofilm reactor (MBBR) for the treatment of reverse osmosis concentrate gathered from local wastewater reuse plant. At stable phase (about 60 days), efficient denitrification performance was obtained with 73.2% ± 19.5% NO3--N average removal and 8.10 ± 3.45 g N/(m3·day) NO3--N average volumetric removal rate. Mass balance analysis showed that 4.84 g A. donax was required to remove 1 g TN. Quantitative real-time PCR analysis results showed that the copy numbers of 16S r-RNA, narG, nirS, nosZ and anammox gene of carrier biofilm and suspended activated sludge in the declination phase (BF2 and AS2) were lower than those of samples in the stable phase (BF1 and AS1), and relatively higher copy numbers of nirS and nirK genes with lower abundance of narG and nosZ genes were observed. High-throughput sequencing analysis was conducted for BF2 and AS2, and similar dominant phyla and classes with different abundance were obtained. The class Gammaproteobacteria affiliated with the phylum Proteobacteria was the most dominant microbial community in both BF2 (52.6%) and AS2 (41.7%). The PICRUSt prediction results indicated that 33 predictive specific genes were related to denitrification process, and the relative abundance of 18 predictive specific genes in BF2 were higher than those in AS2.},
}
@article {pmid31284195,
year = {2019},
author = {Lu, L and Wang, B and Zhang, Y and Xia, L and An, D and Li, H},
title = {Identification and nitrogen removal characteristics of Thauera sp. FDN-01 and application in sequencing batch biofilm reactor.},
journal = {The Science of the total environment},
volume = {690},
number = {},
pages = {61-69},
doi = {10.1016/j.scitotenv.2019.06.453},
pmid = {31284195},
issn = {1879-1026},
abstract = {A strain FDN-01 was isolated from the sequencing batch biofilm reactor (SBBR) which was seeded with wasted activated sludge from a municipal wastewater treatment plant in Shanghai. Bacterium FDN-01 was identified as Thauera sp., and Genbank Sequence_ID was KY393097. By comparing inorganic total nitrogen (TN) removal efficiency by strain FDN-01 under different conditions, the optimal initial pH, carbon source and the ratio of carbon to nitrogen were 7.5, sodium succinate and 4.0, respectively. Inorganic TN removal efficiency was 93% within 3 d while the concentration of nitrate was 100 mg/L, and the type of substrates affected extracellular polymeric substances (EPS) production and the ratio of protein to polysaccharide in the EPS. Further investigation for the application of strain FDN-01 in the SBBRs showed that anoxic ammonia oxidation occurred at room temperature, and the removal efficiencies of inorganic TN were noticeably enhanced by the augmentation of bacterium FDN-01 back into the SBBR. This study provided a promising method of TN removal requiring less carbon source in the wastewater.},
}
@article {pmid31284075,
year = {2019},
author = {Cabrini Carmello, J and Alves, F and Basso, FG and de Souza Costa, CA and Tedesco, AC and Lucas Primo, F and Mima, EGO and Pavarina, AC},
title = {Antimicrobial photodynamic therapy reduces adhesion capacity and biofilm formation of Candida albicans from induced oral candidiasis in mice.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {27},
number = {},
pages = {402-407},
doi = {10.1016/j.pdpdt.2019.06.010},
pmid = {31284075},
issn = {1873-1597},
abstract = {BACKGROUND: Antimicrobial photodynamic therapy (aPDT) has been considered an alternative therapeutic modality for the treatment of Candida infections. However, most studies are focused mainly on microorganism's inactivation efficiency. Here, we evaluated the efficacy of aPDT mediated by chloro-aluminum phthalocyanine encapsulated in cationic nanoemulsions (ClAlP-NE) to treat oral candidiasis in vivo and its effect on the adhesion and biofilm formation of Candida albicans.<br><br>METHODS: For this, mice were immunosuppressed and inoculated with C. albicans to produce oral candidiasis. aPDT and Nystatin were applied for 5 successive sessions. Next, the microbiological evaluation was determined (CFU/ml) and the analyses of virulence factors (adhesion capacity and biofilm formation) were performed. Data were analyzed by Two-way ANOVA (α = 0.05).<br><br>RESULTS: aPDT was as effective as Nystatin reducing 1.4 and 2.0 log10 of the cell viability (p ≤ 0.0001), respectively. Both treatments reduced the adhesion capacity and biofilm formation of C. albicans (p ≤ 0.0001) CONCLUSION: : ClAlP-NE-mediated aPDT was effective in reducing the virulence factors of C. albicans and also to treat induced oral candidiasis in mice.},
}
@article {pmid31283996,
year = {2019},
author = {Palaniraj, S and Murugesan, R and Narayan, S},
title = {Chlorogenic acid- loaded calcium phosphate chitosan nanogel as biofilm degradative materials.},
journal = {The international journal of biochemistry &amp; cell biology},
volume = {114},
number = {},
pages = {105566},
doi = {10.1016/j.biocel.2019.105566},
pmid = {31283996},
issn = {1878-5875},
abstract = {This work describes an effort to develop an antimicrobial agent (chlorogenic acid - CGA) loaded porous nanogel based on calcium phosphate-chitosan (CaPNP@Chi) nanogel with biofilm degradative properties and has potential applications in restorative dentistry. The nanogel was prepared by ionic gelation of calcium phosphate nanoparticles and chitosan in the ratio of 1.25: 1. Chlorogenic acid was loaded to the nanoparticles as an ethanolic solution and the encapsulation efficiency determined by chromatographic techniques. The particle size and morphology of CaPNP@Chi and CaPNP@Chi@CGA was determined by dynamic light scattering and scanning electron microscopic techniques. The minimum inhibitory concentration against S. aureus and K. pneumoniae was determined through the well diffusion method. The biofilm formation and biofilm decay were studied through staining assays. The toxicity, if any of the nanogel was assessed by MTT assay against HaCaT cells. All data were statistically analyzed. The composite had a CGA encapsulation efficiency of 70% and was thermally stable up to 124 °C. The zone of inhibition was found to be 18.7 mm ± 0.6 against S. aureus. CaPNP@Chi@CGA showed a 68% increase in biofilm degradation when compared with the untreated group. Results obtained in this study suggest that the positively charged nanogel interacted with the bacterial cell membrane and brought about the disruption of the cell membrane. Also, CaPNP@Chi@CGA was observed to be nontoxic up to 40 μg/mL to HaCaT cells. These results support the potential of CaPNP@Chi@CGA nanogel for biofilm degradation and its application as filling material in restorative dentistry.},
}
@article {pmid31282384,
year = {2019},
author = {Meroni, G and Zamarian, V and Prussiani, C and Bronzo, V and Lecchi, C and Martino, PA and Ceciliani, F},
title = {The bovine acute phase protein α1-acid glycoprotein (AGP) can disrupt Staphylococcus aureus biofilm.},
journal = {Veterinary microbiology},
volume = {235},
number = {},
pages = {93-100},
doi = {10.1016/j.vetmic.2019.06.007},
pmid = {31282384},
issn = {1873-2542},
abstract = {Staphylococcus aureus biofilm-related infections are of clinical concern due to the capability of bacterial colonies to adapt to a hostile environment. The present study investigated the capability of the acute phase protein alpha 1-acid glycoprotein (AGP) to a) disrupt already established S. aureus biofilm and b) interfere with the biofilm de novo production by using Microtiter Plate assay (MtP) on field strains isolated from infected quarters by assessing. The present study also investigated whether AGP could interfere with the expression of bacterial genes related to biofilm formation (icaA, icaD, icaB, and icaC) and adhesive virulence determinants (fnbA, fnbB, clfA, clfB, fib, ebps, eno) by quantitative real-time PCR (qPCR). The results provided the evidence that AGP could disrupt the biofilm structure only when it was already developed, but could not prevent the de novo biofilm formation. Moreover, AGP could interfere with the expression levels of genes involved in biofilm formation in a dose- and strain-dependent way, by upregulating, or downregulating, icaABC genes and fnbB, respectively. The results presented in this study provide new insights about the direct antibacterial activity of AGP in bovine milk. It remains to be demonstrated the molecular bases of AGP mechanism of action, in particular for what concerns the scarce capability to interact with the de novo formation of biofilm.},
}
@article {pmid31282211,
year = {2019},
author = {Wongkaewkhiaw, S and Taweechaisupapong, S and Anutrakunchai, C and Nazmi, K and Bolscher, JGM and Wongratanacheewin, S and Kanthawong, S},
title = {D-LL-31 in combination with ceftazidime synergistically enhances bactericidal activity and biofilm destruction in Burkholderia pseudomallei.},
journal = {Biofouling},
volume = {35},
number = {5},
pages = {573-584},
doi = {10.1080/08927014.2019.1632835},
pmid = {31282211},
issn = {1029-2454},
abstract = {Melioidosis is a severe disease caused by Burkholderia pseudomallei. The biofilm of B. pseudomallei acquires resistance to several antibiotics and may be related to relapse in melioidosis patients. Here, the killing activity of antimicrobial peptides (LL-37, LL-31) and the D-enantiomers (D-LL-37, D-LL-31) in combination with ceftazidime (CAZ) against B. pseudomallei 1026b, H777 and a biofilm mutant M10, derived from H777 grown under biofilm-stimulating conditions was observed. Using static conditions, D-LL-31 exhibited the strongest killing activity against the three isolates in a dose-dependent manner. IC50 values for D-LL-31 ranged from 1 to 6 µM, for isolates M10, H777, and 1026b, respectively. Moreover, D-LL-31 combined with CAZ synergistically decreased the IC50 values of the peptide and antibiotic and caused also disruption of biofilms of B. pseudomallei 1026b under flow conditions. Thus a combination of D-LL-31 and CAZ may enhance the efficacy of the currently used antibiotic treatments against B. pseudomallei.},
}
@article {pmid31282200,
year = {2019},
author = {Maquera Huacho, PM and Rodriguez Herrero, E and Verspecht, T and Pauwels, M and Marcantonio, E and Palomari Spolidorio, DM and Teughels, W},
title = {Terpinen-4-ol and carvacrol affect multi-species biofilm composition.},
journal = {Biofouling},
volume = {35},
number = {5},
pages = {561-572},
doi = {10.1080/08927014.2019.1630386},
pmid = {31282200},
issn = {1029-2454},
abstract = {The aim of this study was to investigate the cytotoxic activity and inhibitory effect of terpinen-4-ol (T4ol) and carvacrol against single- and multi-species biofilms. The toxicity of each compound was tested on oral keratinocytes and evaluated by XTT assay. Inhibition and eradication of single-species biofilms were analyzed by crystal violet assay and the effect on multi-species biofilm composition was evaluated by qPCR. T4ol and carvacrol did not affect the epithelial cell viability, in contrast to chlorhexidine, which showed a high cytotoxic effect. Inhibition and eradication of single-species biofilms treated with T4ol and carvacrol were observed. The same inhibitory effect was observed for multi-species biofilms, especially on periodontal pathogens. In conclusion, specific concentrations of T4ol and carvacrol without toxicity towards the epithelial cells reduced the numbers of periodontal pathogens in single- and multi-species biofilms.},
}
@article {pmid31280338,
year = {2019},
author = {Wang, X and Shen, X and Wang, Z and Kong, Y},
title = {Viscoelasticity variation in a biofilm-mediated Bacillus subtilis suspension induced by adding polyethylene glycol.},
journal = {European biophysics journal : EBJ},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00249-019-01385-0},
pmid = {31280338},
issn = {1432-1017},
support = {11772047//National Natural Science Foundation of China/ ; 11620101001//Key international collaborating Project from National Natural Science Foundation of China/ ; },
abstract = {Recent experiments show that synthetic polymers can influence the degree of microbial aggregation and the rheological properties of bacterial suspensions, the study of which can help us control biofilm formation. In this article, we add polyethylene glycol (PEG) with various molecular weights and concentrations into two types Bacillus subtilis cell cultures, Luria Broth (LB) and Minimal Salts glutamate glycerol (MSgg), respectively. We first observe cell clusters in cell suspensions with various concentrations of PEG, and measure cluster size in both static and dynamic fluid environments. We find that cells gather together into big clusters and most of the cells are arranged longitudinally; and the large cell clusters are divided into smaller aggregates under fluid shear. We then use a rheometer to measure the viscoelastic properties of various cell cultures, to represent the degree of aggregation of the bacterial suspensions. We find the storage modulus, the loss modulus and the viscosity of bacterial suspensions not only depend on the cell aggregation but also depend on the directionality of cellular motion.},
}
@article {pmid31280150,
year = {2019},
author = {Zakaria, BS and Lin, L and Dhar, BR},
title = {Shift of biofilm and suspended bacterial communities with changes in anode potential in a microbial electrolysis cell treating primary sludge.},
journal = {The Science of the total environment},
volume = {689},
number = {},
pages = {691-699},
doi = {10.1016/j.scitotenv.2019.06.519},
pmid = {31280150},
issn = {1879-1026},
abstract = {This study, for the first time, documented microbial community shifts in response to the changes in anode potential in a microbial electrolysis cell (MEC) operated with primary sludge. At an anode potential of -0.4 V vs. Ag/AgCl, the MEC showed COD and VSS removal efficiencies of 73 ± 1% and 75 ± 2%, respectively. The volumetric current density and specific hydrogen production rate were 23 ± 1.2 A/m3, and 145 ± 4.1 L/m3-d, respectively. The anodic microbial community was consisted of various fermentative/hydrolytic bacteria (e.g., Bacteroides and Dysgonomonas) and anode-respiring bacteria (Geobacter), while different hydrolytic/fermentative bacteria were abundant in suspension. The MEC showed substantially inferior performance along with a higher accumulation of various volatile fatty acids when the anode potential was switched to more positive values (0 V and +0.4 V). Both biofilms and suspended communities were also shifted when the anode potential was changed. Notably, at +0.4 V, Geobacter genus entirely disappeared from the biofilms, while Paludibacter species (known fermentative bacteria) were selectively enriched in biofilms. Also, the relative abundance of genus Bacteroides (known hydrolytic bacteria) substantially decreased in both biofilms and suspension, which was correlated with the inferior hydrolysis of VSS. Quantitative comparison of biofilms and suspended microbial communities at different anode potentials revealed a sharp decrease in bacterial cell numbers in anode biofilms after changing anode potential from -0.4 V to +0.4 V. By contrast, bacterial cell numbers in suspension were slightly decreased. Collectively, these results provide new insights into the role of anode potential in shaping key microbial players associated with hydrolysis/fermentation and anodic respiration processes when MECs are operated with real biowastes.},
}
@article {pmid31279761,
year = {2019},
author = {Parvin, F and Hu, H and Whiteley, GS and Glasbey, T and Vickery, K},
title = {Difficulty in removing biofilm from dry surfaces.},
journal = {The Journal of hospital infection},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jhin.2019.07.005},
pmid = {31279761},
issn = {1532-2939},
abstract = {Cleaning is fundamental to infection control. This report demonstrates that a Staphylococcus aureus biofilm is significantly more difficult to remove than dried planktonic bacteria. A single wiping action removed >99.9% (>3 log10) of dried planktonic bacteria, whereas only 1.4 log10 of biofilm (96.66%) was removed by 50 wiping actions with a standardized wiping process.},
}
@article {pmid31279340,
year = {2019},
author = {Velsko, IM and Fellows Yates, JA and Aron, F and Hagan, RW and Frantz, LAF and Loe, L and Martinez, JBR and Chaves, E and Gosden, C and Larson, G and Warinner, C},
title = {Microbial differences between dental plaque and historic dental calculus are related to oral biofilm maturation stage.},
journal = {Microbiome},
volume = {7},
number = {1},
pages = {102},
doi = {10.1186/s40168-019-0717-3},
pmid = {31279340},
issn = {2049-2618},
support = {143/108//John Fell Fund, University of Oxford/ ; BCS-1516633//National Science Foundation (US)/ ; },
abstract = {BACKGROUND: Dental calculus, calcified oral plaque biofilm, contains microbial and host biomolecules that can be used to study historic microbiome communities and host responses. Dental calculus does not typically accumulate as much today as historically, and clinical oral microbiome research studies focus primarily on living dental plaque biofilm. However, plaque and calculus reflect different conditions of the oral biofilm, and the differences in microbial characteristics between the sample types have not yet been systematically explored. Here, we compare the microbial profiles of modern dental plaque, modern dental calculus, and historic dental calculus to establish expected differences between these substrates.<br><br>RESULTS: Metagenomic data was generated from modern and historic calculus samples, and dental plaque metagenomic data was downloaded from the Human Microbiome Project. Microbial composition and functional profile were assessed. Metaproteomic data was obtained from a subset of historic calculus samples. Comparisons between microbial, protein, and metabolomic profiles revealed distinct taxonomic and metabolic functional profiles between plaque, modern calculus, and historic calculus, but not between calculus collected from healthy teeth and periodontal disease-affected teeth. Species co-exclusion was related to biofilm environment. Proteomic profiling revealed that healthy tooth samples contain low levels of bacterial virulence proteins and a robust innate immune response. Correlations between proteomic and metabolomic profiles suggest co-preservation of bacterial lipid membranes and membrane-associated proteins.<br><br>CONCLUSIONS: Overall, we find that there are systematic microbial differences between plaque and calculus related to biofilm physiology, and recognizing these differences is important for accurate data interpretation in studies comparing dental plaque and calculus.},
}
@article {pmid31279321,
year = {2019},
author = {Shi, J and Han, Y and Xu, C and Han, H},
title = {Enhanced biodegradation of coal gasification wastewater with anaerobic biofilm on polyurethane (PU), powdered activated carbon (PAC), and biochar.},
journal = {Bioresource technology},
volume = {289},
number = {},
pages = {121487},
doi = {10.1016/j.biortech.2019.121487},
pmid = {31279321},
issn = {1873-2976},
abstract = {The primary objective was to explore the feasibility of anaerobic biofilm on polyurethane (PU), powdered activated carbon (PAC), and biochar in strengthening anaerobic degradation of phenolic compounds and selected nitrogen heterocyclic compounds (NHCs) in coal gasification wastewater (CGW). When total phenols (TPh) was less than 300 mg/L, PAC-based biofilm was more efficient. Whereas, when the TPh concentration was more than 450 mg/L, PU-based biofilm performed the optimal degradation efficiency. Furthermore, microbial community structure analysis showed that PAC and biochar had little effect on the microbial community structure after 120 days of operation, while the addition of PU could lead to the enrichment of Giesbergeria, Caldisericum, Thauera, Methanolinea, and Methanoregula.},
}
@article {pmid31279316,
year = {2019},
author = {Cui, YX and Guo, G and Ekama, GA and Deng, YF and Chui, HK and Chen, GH and Wu, D},
title = {Elucidating the biofilm properties and biokinetics of a sulfur-oxidizing moving-bed biofilm for mainstream nitrogen removal.},
journal = {Water research},
volume = {162},
number = {},
pages = {246-257},
doi = {10.1016/j.watres.2019.02.061},
pmid = {31279316},
issn = {1879-2448},
abstract = {The sulfide-oxidizing autotrophic denitrification (SOAD) process offers a feasible alternative to mainstream heterotrophic denitrification in treating domestic sewage with insufficient organics. Previously SOAD has been successfully applied in a moving-bed biofilm reactor (MBBR). However, the biofilm properties and biokinetics are still not thoroughly understood. The present study was therefore designed to investigate these features of sulfur-oxidizing biofilms (SOBfs) cultivated in a lab-scale MBBR under stable operation for over a year. The biofilms developed were 160 μm thick, had an uneven and porous surface on which elemental sulfur (S0) accumulated, and the SOB biomass was highly diverse. The bioprocess kinetics were evaluated through 12 batch experiments. The results were interpreted by adopting a two-step sulfide oxidation model (sulfide→S0 and S0→ sulfate) with all specific rates having a linear regression coefficient of R2 > 0.9. Moreover, the inhibitory kinetic analysis revealed that 1) the maximum treatment capacity (about 480 mg S/(m2·h) and 80 mg N/(m2·h)) was observed at low sulfide level (40 mg S/L), while higher sulfide level (60-150 mg S/L) showed increasing inhibition on the oxidation of both sulfide and sulfur and denitrification. 2) The denitritation activity decreased by up to 43% when free nitrous acid reached a maximum of 8.6 μg N/L, whereas the oxidation of sulfide and sulfur did not have any significant effect. Interestingly, two physiologically diverse SOB groups were found in this special biofilm. The mechanisms of the cooperation and competition for electron donors and acceptors between these two SOB clades are proposed. The results of this study greatly enhance our understanding of the design and optimization of SOAD-MBBR for mainstream nitrogen removal.},
}
@article {pmid31278701,
year = {2019},
author = {Liaqat, I and Liaqat, M and Tahir, HM and Haq, I and Ali, NM and Arshad, M and Arshad, N},
title = {Motility effects biofilm formation in Pseudomonas aeruginosa and Enterobacter cloacae.},
journal = {Pakistan journal of pharmaceutical sciences},
volume = {32},
number = {3},
pages = {927-932},
pmid = {31278701},
issn = {1011-601X},
abstract = {Chronic infections caused by gram negative bacteria are the mains reasons to have morbidity and death in patients, despite using high doses of antibiotics applied to cure diseases producing by them. This study was designed to identify the role of flagella in biofilm formation Ten pure strains were collected from our lab. Morphological variation and motility assays led us to study two strains in detail. They were characterized biochemically, physiologically and genetically. Biofilm formation analysis was performed using test tube assay, congo red assay and liquid-interface coverslip assay. In order to disrupt flagella of studied strains, blending was induced for 5, 10 and 15 minutes followed by centrifugation and observing motility using motility test. Biofilm quantification of wild type (parental) and blended strains was done using test tube and liquid interface coverslip assays. 16S rRNA sequencing identified strains as Pseudomonas aeroginosa and Enterobacter cloacae. Significant biofilm formation (p>0.05) by was observed after 72 and 18 hours using test tube and liquid-interface coverslip assays respectively. Flagellar disruption showed that 15 minutes blending caused significant reduction in both strains, hence demonstrated that flagellar mediated motility could be a potent strategy to stabilize aggregate and invest resources for biofilm formation in P. aeruginosa and E. cloacae.},
}
@article {pmid31278369,
year = {2019},
author = {Hou, J and Wang, C and Rozenbaum, RT and Gusnaniar, N and de Jong, ED and Woudstra, W and Geertsema-Doornbusch, GI and Atema-Smit, J and Sjollema, J and Ren, Y and Busscher, HJ and van der Mei, HC},
title = {Bacterial Density and Biofilm Structure Determined by Optical Coherence Tomography.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {9794},
doi = {10.1038/s41598-019-46196-7},
pmid = {31278369},
issn = {2045-2322},
abstract = {Optical-coherence-tomography (OCT) is a non-destructive tool for biofilm imaging, not requiring staining, and used to measure biofilm thickness and putative comparison of biofilm structure based on signal intensity distributions in OCT-images. Quantitative comparison of biofilm signal intensities in OCT-images, is difficult due to the auto-scaling applied in OCT-instruments to ensure optimal quality of individual images. Here, we developed a method to eliminate the influence of auto-scaling in order to allow quantitative comparison of biofilm densities in different images. Auto- and re-scaled signal intensities could be qualitatively interpreted in line with biofilm characteristics for single and multi-species biofilms of different strains and species (cocci and rod-shaped organisms), demonstrating qualitative validity of auto- and re-scaling analyses. However, specific features of pseudomonas and oral multi-species biofilms were more prominently expressed after re-scaling. Quantitative validation was obtained by relating average auto- and re-scaled signal intensities across biofilm images with volumetric-bacterial-densities in biofilms, independently obtained using enumeration of bacterial numbers per unit biofilm volume. The signal intensities in auto-scaled biofilm images did not significantly relate with volumetric-bacterial-densities, whereas re-scaled intensities in images of biofilms of widely different strains and species increased linearly with independently determined volumetric-bacterial-densities in the biofilms. Herewith, the proposed re-scaling of signal intensity distributions in OCT-images significantly enhances the possibilities of biofilm imaging using OCT.},
}
@article {pmid31277901,
year = {2019},
author = {Cameron, R and Claudia, E and Ping, W and Erin, S and Ruparel, NB},
title = {Effect of a Residual Biofilm on Release of Transforming Growth Factor β1 from Dentin.},
journal = {Journal of endodontics},
volume = {45},
number = {9},
pages = {1119-1125},
doi = {10.1016/j.joen.2019.05.004},
pmid = {31277901},
issn = {1878-3554},
abstract = {INTRODUCTION: Several studies have reported regeneration of the pulp-dentin complex when treating noninfected root canal systems. However, current protocols applied to infected root canal systems are much less predictable for the formation of dentin. Converging lines of evidence implicate residual biofilm as an important factor for these variable histologic outcomes. Here we studied the effect of a residual polymicrobial biofilm on the release of transforming growth factor beta 1 (TGF-β1) from dentin. We hypothesized that the presence of bacterial biofilm attenuates the release of bioactive molecules from dentin.<br><br>METHODS: Using bacteria commonly found in infected immature teeth, we developed a multispecies biofilm in an organotypic root canal model. Root segments were then subjected to various irrigation or intracanal medicament protocols. Subsequently, the release of TGF-β1 from dentin was measured using the enzyme-linked immunosorbent assay.<br><br>RESULTS: Our data show that sterile root segments released greater amounts of TGF-β1 when conditioned with 17% EDTA alone (P < .001) or with the combination of 1.5% sodium hypochlorite and 17% EDTA (P < .05) compared with root segments infected with the multispecies biofilm. Similar results were also observed with the intracanal medicament protocol. Sterile root segments medicated with various concentrations of triple antibiotic paste and full-strength calcium hydroxide released greater amounts of TGF-β1 when compared with their infected counterparts.<br><br>CONCLUSIONS: This is the first study to report the detrimental effects of a residual biofilm on dentin conditioning and, therefore, the release of growth factors critical for regenerative procedures.},
}
@article {pmid31276938,
year = {2019},
author = {Huang, Y and Thompson, T and Wang, Y and Yu, Q and Zhu, L and Xu, X and Wen, ZT and Townsend, JA},
title = {Analysis of cariogenic potential of alternative milk beverages by in vitro Streptococcus mutans biofilm model and ex vivo caries model.},
journal = {Archives of oral biology},
volume = {105},
number = {},
pages = {52-58},
doi = {10.1016/j.archoralbio.2019.05.033},
pmid = {31276938},
issn = {1879-1506},
support = {R01 DE019452/DE/NIDCR NIH HHS/United States ; R01 DE026782/DE/NIDCR NIH HHS/United States ; },
abstract = {OBJECTIVE: To evaluate the potential of various alternative milk beverages to support bacterial biofilm formation and acid production and cause unbalanced demineralization.<br><br>DESIGN: in vitro assays were used to examine the ability of the beverages to support Streptococcus mutans' biofilm formation and acid production from sugar fermentation and the capacity of the beverages to buffer pH changes. Biofilm formation was done using 96-well plate model. Acid production was measured using L-Lactate assay kit, and the buffering capacity was assessed by pH titration. For ex vivo caries model, enamel and dentine slabs and S. mutans biofilms were exposed to selected alternative milk beverages three times a day, 30 min each, and by the end of the experiments, slab's demineralization was assessed by loss of surface microhardness.<br><br>RESULTS: Of the alternative milk beverages tested in this study, Original Almond consistently supported the most S. mutans biofilms, followed by Chocolate Cashew Milk, while the least biofilms were measured with Unsweetened Flax Milk. The most acids and the lowest culture pH were measured with Toasted Coconut Almond Milk, while the least buffering capacity was measured with Unsweetened Coconut Milk. The results of ex vivo caries model showed that like Bovine Whole Milk, repeated exposure to Original Almond led to significant enamel and dentine slab demineralization, when compared to those exposed to saline as a control (P < 0.001).<br><br>CONCLUSIONS: These results further provide support that popular alternative milk beverages, especially those with supplemental sugars, are potentially cariogenic.},
}
@article {pmid31275531,
year = {2019},
author = {Schoilew, K and Ueffing, H and Dalpke, A and Wolff, B and Frese, C and Wolff, D and Boutin, S},
title = {Bacterial biofilm composition in healthy subjects with and without caries experience.},
journal = {Journal of oral microbiology},
volume = {11},
number = {1},
pages = {1633194},
doi = {10.1080/20002297.2019.1633194},
pmid = {31275531},
issn = {2000-2297},
abstract = {Objective:The composition of the oral microbiome differs distinctively between subjects with and without active caries. Still, caries research has mainly been focused on states of disease; aspects about how biofilm composition and structure maintain oral health still remain widely unclear. Therefore, the aim of the study was to compare the healthy oral microbiome of caries-free adult subjects with and without former caries experience using next generation sequencing methods. Methods: 46 samples were collected from subjects without any signs of untreated active caries. Samples of pooled supragingival plaque from 19 subjects without caries experience (NH; DMFT = 0) and 27 subjects with 'caries experience' (CE; DMFT > 0 [F(T)> 0; D(T)= 0]) were analyzed by 16S ribosomal RNA amplicon sequencing. Results: Subjects with caries experience did not exhibit a dramatically modified supragingival plaque microbiome. However, we observed a slight and significant modification between the two groups, validated by PERMANOVA (NH vs. CE: R2 0.04; p= 0.039). The composition of the microbiome of subjects with caries experience indicates a tendency to lower α-diversity and richness. Subjects without caries experience showed a significant higher evenness compared to patients with previous caries. LDA effect size (LEfSe) analysis demonstrated that the genus Haemophilus is significantly more frequent in patients with caries experience. For the group without caries experience LefSe analysis showed a set of 11 genera being significantly more frequent, including Corynebacterium, Fusobacterium, Capnocytophaga, Porphyromonas, Prevotella,and Leptotrichia.Conclusion: The analysis of the oral microbiome of subjects with and without caries experience indicates specific differences. With the presence of Corynebacterium and Fusobacterium subjects without caries experience exhibited more frequently organisms that are considered to be main actors in structural plaque formation and integration. The abundance of Corynebacterium might be interpreted as a signature for dental health.},
}
@article {pmid31275529,
year = {2019},
author = {Shany-Kdoshim, S and Polak, D and Houri-Haddad, Y and Feuerstein, O},
title = {Killing mechanism of bacteria within multi-species biofilm by blue light.},
journal = {Journal of oral microbiology},
volume = {11},
number = {1},
pages = {1628577},
doi = {10.1080/20002297.2019.1628577},
pmid = {31275529},
issn = {2000-2297},
abstract = {Objectives: The aim of the study was to characterize the immediate and delayed effects of non-coherent blue-light treatment on the composition and viability of an in vitro biofilm composed of anaerobic multispecies, as well as the mechanisms involved. Methods: A multispecies biofilm was constructed of Streptococcus sanguinis, Actinomyces naeslundii, Porphyromonas gingivalis and Fusobacterium nucleatum, test groups were exposed to blue light. The multispecies biofilm was explored with a newly developed method based on flow cytometry and confocal microscopy. The involvement of the paracrine pathway in the phototoxic mechanism was investigated by a crossover of the supernatants between mono-species P. gingivalis and F. nucleatum biofilms. Results: Blue light led to a reduction of about 50% in the viable pathogenic bacteria P. gingivalis and F. nucleatum, vs that in the non-exposed biofilm. Biofilm thickness was also reduced by 50%. The phototoxic effect of blue light on mono-species biofilm was observed in P. gingivalis, whereas F. nucleatum biofilm was unaffected. A lethal effect was obtained when the supernatant of P. gingivalis biofilm previously exposed to blue light was added to the F. nucleatum biofilm. The effect was circumvented by the addition of reactive oxygen species (ROS) scavengers to the supernatant. Conclusion: Blue-light has an impact on the bacterial composition and viability of the multispecies biofilm. The phototoxic effect of blue light on P. gingivalis in biofilm was induced directly and on F. nucleatum via ROS mediators of the paracrine pathway. This phenomenon may lead to a novel approach for 'replacement therapy,' resulting in a less periodonto-pathogenic biofilm.},
}
@article {pmid31275267,
year = {2019},
author = {Zhu, YL and Hou, HM and Zhang, GL and Wang, YF and Hao, HS},
title = {AHLs Regulate Biofilm Formation and Swimming Motility of Hafnia alvei H4.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1330},
doi = {10.3389/fmicb.2019.01330},
pmid = {31275267},
issn = {1664-302X},
abstract = {The aim of this study was to evaluate the role of N-acyl homoserine lactones (AHLs) in the regulation of swimming motility of Hafnia alvei H4 and its biofilm formation on 96-well plate, glass and stainless-steel surfaces. The luxI gene, which codes for an enzyme involved in AHL synthesis, was deleted to generate a luxI mutant (ΔluxI). The mutant produced no AHL, and the relative expression of the luxR gene was significantly (P < 0.05) decreased. In addition, qRT-PCR analysis showed that the relative expression of the luxR gene in ΔluxI was stimulated by the presence of exogenous AHLs (C4-HSL, C6-HSL, and 3-o-C8-HSL) added at concentrations ranging from of 50-250 μg/ml. Among the three AHLs, C6-HSL had the strongest effect. The ability of ΔluxI to form biofilm on 96-well plate, glass and stainless-steel surfaces was significantly reduced (P < 0.05) compared with the wild type (WT), but was increased when provided with 150 μg/ml C4-HSL, whereas C6-HSL and 3-o-C8-HSL had no effect. Scanning electron microscopy analysis of the biofilm revealed less bacteria adhering to the surface of stainless-steel and fewer filaments were found binding to the cells compared with the WT. Furthermore, ΔluxI also exhibited significant (P < 0.05) decrease in the expression of biofilm- and swimming motility-related genes, flgA, motA and cheA, consistent with the results observed for biofilm formation and swimming motility. Taken together, the results suggested that in H. alvei H4, C4-HSL may act as an important molecular signal through regulating the ability of the cells to form biofilm, as well as through regulating the swimming motility of the cell, and this could provide a new way to control these phenotypes of H. alvei in food processing.},
}
@article {pmid31273528,
year = {2019},
author = {Hasegawa, T and Takenaka, S and Ohsumi, T and Ida, T and Ohshima, H and Terao, Y and Naksagoon, T and Maeda, T and Noiri, Y},
title = {Effect of a novel glass ionomer cement containing fluoro-zinc-silicate fillers on biofilm formation and dentin ion incorporation.},
journal = {Clinical oral investigations},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00784-019-02991-0},
pmid = {31273528},
issn = {1436-3771},
support = {15H05021//Japan Society for the Promotion of Science/ ; None//GC Corporation/ ; },
abstract = {OBJECTIVES: This study is aimed at evaluating the effect of a new glass ionomer cement (GIC) containing fluoro-zinc-silicate fillers on biofilm formation and ion incorporation.<br><br>MATERIALS AND METHODS: Streptococcus mutans biofilms were developed on two GIC materials: Caredyne Restore (CD) and Fuji VII (FJ); and hydroxyapatite (HA) for 24 h at 37 °C using a flow cell system. The morphological structure and bacterial viability were analyzed using a confocal laser scanning microscopy. Bacterial adhesion during the initial 2 h was also assessed by viable cell counting. To study the ion incorporation, restored cavities prepared on the root surfaces of human incisors were subjected to the elemental mapping of the zinc and fluoride ions in the GIC-dentin interface using a wavelength-dispersive X-ray spectroscopy electron probe microanalyzer.<br><br>RESULTS: Morphological observations revealed that biofilm formation in the CD group was remarkably inhibited compared with the HA and FJ groups, exhibiting sparse, thinner biofilm clusters. The microorganisms adhering to the CD group were significantly inhibited, revealing 2.9 ± 0.4 for CD, 4.9 ± 0.2 for FJ, and 5.4 ± 0.4 log colony-forming units (CFU) for HA. The CD zinc ion incorporation depth was 72.2 ± 8.0 μm. The fluoride penetration of CD was three times deeper than that of FJ; this difference was statistically significant (p < 0.05).<br><br>CONCLUSIONS: Enhanced by the incorporation of zinc and fluoride ions, the new GIC inhibited biofilm formation by interfering with bacterial adhesion.<br><br>CLINICAL RELEVANCE: A novel GIC comprised of fluoro-zinc-silicate fillers may improve clinical outcomes, such as root caries and minimally invasive dentistry.},
}
@article {pmid31272369,
year = {2019},
author = {Cai, W and De La Fuente, L and Arias, CR},
title = {Transcriptome analysis of the fish pathogen Flavobacterium columnare in biofilm suggests calcium role in pathogenesis.},
journal = {BMC microbiology},
volume = {19},
number = {1},
pages = {151},
doi = {10.1186/s12866-019-1533-4},
pmid = {31272369},
issn = {1471-2180},
support = {Internal Grant//Auburn University/ ; N/A//USDA-HATCH/ ; },
abstract = {BACKGROUND: Flavobacterium columnare is the causative agent of columnaris disease that affects cultured freshwater fishes worldwide. F. columnare easily colonizes surfaces by forming biofilm, which helps the pathogen resist antibiotic and disinfectant treatments. Previously, we had shown that increasing concentrations of calcium (Ca2+) promoted biofilm formation by F. columnare. The objective of this study was to further characterize the role of Ca2+ on biofilm formation and to compare the transcriptome profiles of planktonic and biofilm cells.<br><br>RESULTS: RNA-Seq analysis was conducted to identify genes that were differentially expressed between the following states: i) planktonic cells in control medium (P), ii) planktonic cells in calcium-enriched medium (P/Ca), and iii) biofilm cells in calcium-enriched medium (B/Ca). Overall, we identified 441 significant (FDR-adjusted p < 0.05, fold change > 2) differentially expressed genes (DEGs) between P and B/Ca samples; 112 significant DEGs between P/Ca and B/Ca samples, and 175 significant DEGs between P/Ca and P samples, corresponding to 15.87, 4.03 and 6.30% of the total protein-coding sequences, respectively. The significant DEGs fell into different functional categories including iron acquisition, oxidative stress response, extracellular protein secretion, and respiratory metabolism.<br><br>CONCLUSIONS: Our results posit Ca2+ as a critical signal in regulating bacterial surface adhesion and biofilm formation in F. columnare. Living in biofilm elicited a shift in several metabolic pathways that allowed the cells to cope with oxidative stress and nutrient starvation. In addition, Ca2+ supplementation induced the expression of putative virulence factors in F. columnare, such as extracellular protein secretion and iron acquisition.},
}
@article {pmid31271350,
year = {2019},
author = {Romera, D and Aguilera-Correa, JJ and Gadea, I and Viñuela-Sandoval, L and García-Rodríguez, J and Esteban, J},
title = {Candida auris: a comparison between planktonic and biofilm susceptibility to antifungal drugs.},
journal = {Journal of medical microbiology},
volume = {68},
number = {9},
pages = {1353-1358},
doi = {10.1099/jmm.0.001036},
pmid = {31271350},
issn = {1473-5644},
abstract = {Introduction.Candida auris is a pathogenic yeast that mainly affects immunosuppressed patients and those with implanted medical devices. This pathogen also displays elevated resistance to common antifungals and high survival and spreading capacities. Since no antifungal breakpoints have yet been defined for this pathogen, the data obtained here can be useful for further research concerning treatment or implementation of a prevention and disinfection protocol. Our aim was to study the antifungal resistance of C. auris to current antifungals in planktonic and sessile states. Using confocal laser scanning microscopy and viable biomass production, we demonstrated the ability of C. auris to develop a mature biofilm. We compared the minimal inhibitory concentration (MIC) and the minimal biofilm eradication concentration (MBEC) for the C. auris DSM 21092 strain plus two clinical isolates, and the results were compared with those obtained for Candida albicans and Candida parapsilosis, two species strongly linked to bloodstream infections and infections associated with biomaterials. We found that the clinical isolates of C. auris were resistant to fluconazole and sensitive to echinocandins and polyenes. The C. auris biofilms did not show susceptibility to any antifungal agent, showing MBECs that were up to 512-fold higher than the MICs. These findings highlight the importance of biofilm formation as a key factor underlying the resistance of this species to antifungals and suggest that the presence of implantable medical devices is one of the major risk factors in immunocompromised patients.},
}
@article {pmid31271299,
year = {2019},
author = {Pereira-Ribeiro, PM and Sued-Karam, BR and Faria, YV and Nogueira, BA and Colodette, SS and Fracalanzza, SE and Duarte, JL and Júnior, RH and Mattos-Guaraldi, AL},
title = {Influence of antibiotics on biofilm formation by different clones of nosocomial Staphylococcus haemolyticus.},
journal = {Future microbiology},
volume = {14},
number = {},
pages = {789-799},
doi = {10.2217/fmb-2018-0230},
pmid = {31271299},
issn = {1746-0921},
abstract = {Staphylococcus haemolyticus is the most common organism among clinical isolatesof methicillin-resistant staphylococci. Aim: This study evaluated the ability to produce biofilm with the presence of the antibiotics (1/4 minimum inhibitory concentrations) of S. haemolyticus strains isolated from blood culture. Methods: Clonal distribution was assessed in pulsed-field gel electrophoresis. PCR assays were performed to detect mecA, icaA, aap, atlE, atl, fbp genes. S. haemolyticus strains grown in the presence of the antibiotics were investigated for biofilm formation on glass, polystyrene and catheter surfaces. Results: Biofilm formation was independent of the presence of the icaA and mecA genes, pulsed-field gel electrophoresis type. Vancomycin, oxacillin, moxifloxacin, rifampicin, teicoplanin, tigecycline and linezolid did not inhibit biofilm formation on abiotic surfaces. Conclusion: This study demonstrated that the biofilm formation process is complex and may not be related to ica gene carriage. Furthermore, in this study the biofilm formation was increased in the presence of antimicrobial agents.},
}
@article {pmid31269803,
year = {2019},
author = {Yang, X and Zhang, Z and Huang, Z and Zhang, X and Li, D and Sun, L and You, J and Pan, X and Yang, H},
title = {A putative LysR-type transcriptional regulator inhibits biofilm synthesis in Pseudomonas aeruginosa.},
journal = {Biofouling},
volume = {35},
number = {5},
pages = {541-550},
doi = {10.1080/08927014.2019.1627337},
pmid = {31269803},
issn = {1029-2454},
abstract = {Biofilm formation is an important virulence factor which is controlled by complex regulatory circuits in Pseudomonas aeruginosa. In this work, a biofilm hyper-producing strain, P2-7, was selected from a collection of transposon insertion mutants in which the PA2121 gene was disrupted. PA2121 was predicted as a putative LysR-type regulator. Analyses showed that it was involved in early biofilm formation, mature biofilm development, and colony morphology. Quantitative measurements revealed that PA2121 repressed biosynthesis of extracellular polysaccharides (alginate, psl and pel). Furthermore, it was observed that PA2121 was self-regulated, highly expressed in the early phase of biofilm development, and subject to the negative regulation by a biofilm synthesis regulator SrpA that binds directly to the PA2121 gene promoter. Collectively, this study proposes that PA2121 is a novel biofilm synthesis repressor (BsrA) in P. aeruginosa.},
}
@article {pmid31268675,
year = {2019},
author = {Blanco-Cabra, N and Vega-Granados, K and Moya-Andérico, L and Vukomanovic, M and Parra, A and Álvarez de Cienfuegos, L and Torrents, E},
title = {Novel Oleanolic and Maslinic Acid Derivatives as a Promising Treatment against Bacterial Biofilm in Nosocomial Infections: An in Vitro and in Vivo Study.},
journal = {ACS infectious diseases},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsinfecdis.9b00125},
pmid = {31268675},
issn = {2373-8227},
abstract = {Oleanolic acid (OA) and maslinic acid (MA) are pentacyclic triterpenic compounds that abound in industrial olive oil waste. These compounds have renowned antimicrobial properties and lack cytotoxicity in eukaryotic cells as well as resistance mechanisms in bacteria. Despite these advantages, their antimicrobial activity has only been tested in vitro, and derivatives improving this activity have not been reported. In this work, a set of 14 OA and MA C-28 amide derivatives have been synthesized. Two of these derivatives, MA-HDA and OA-HDA, increase the in vitro antimicrobial activity of the parent compounds while reducing their toxicity in most of the Gram-positive bacteria tested, including a methicillin-resistant Staphylococcus aureus-MRSA. MA-HDA also shows an enhanced in vivo efficacy in a Galleria mellonella invertebrate animal model of infection. A preliminary attempt to elucidate their mechanism of action revealed that these compounds are able to penetrate and damage the bacterial cell membrane. More significantly, their capacity to reduce antibiofilm formation in catheters has also been demonstrated in two sets of conditions: a static and a more challenged continuous-flow S. aureus biofilm.},
}
@article {pmid31268665,
year = {2019},
author = {Banerjee, P and Chanchal, and Jain, D},
title = {Sensor I Regulated ATPase Activity of FleQ Is Essential for Motility to Biofilm Transition in Pseudomonas aeruginosa.},
journal = {ACS chemical biology},
volume = {14},
number = {7},
pages = {1515-1527},
doi = {10.1021/acschembio.9b00255},
pmid = {31268665},
issn = {1554-8937},
abstract = {Members of the AAA+ (ATPase associated with various cellular activities) family of ATPases couple chemical energy derived from ATP hydrolysis for generation of mechanical force, resulting in conformational changes. The hydrolysis is brought about by highly conserved domains and motifs. The sensor I motif is critical for sensing and hydrolysis of the nucleotide. Pseudomonas aeruginosa FleQ is an ATPase that is a positive regulator of flagellar gene expression. We have determined the crystal structures of the ATPase domain of wild-type FleQ and sensor I mutants H287N and H287A in complex with ATPγS and Mg2+ to 2.4, 1.95, and 2.25 Å resolution, respectively. The structural data highlight the role of sensor I in regulating the ATPase activity. The in vitro and in vivo data demonstrate that the moderate ATPase activity of FleQ due to the presence of histidine in sensor I is essential for maintaining the monotrichous phenotype and for the rapid motility to biofilm transition.},
}
@article {pmid31262835,
year = {2019},
author = {Vogeleer, P and Vincent, AT and Chekabab, SM and Charette, SJ and Novikov, A and Caroff, M and Beaudry, F and Jacques, M and Harel, J},
title = {Regulation of waaH by PhoB during Pi Starvation Promotes Biofilm Formation by Escherichia coli O157:H7.},
journal = {Journal of bacteriology},
volume = {201},
number = {18},
pages = {},
doi = {10.1128/JB.00093-19},
pmid = {31262835},
issn = {1098-5530},
abstract = {In open environments such as water, enterohemorrhagic Escherichia coli O157:H7 responds to inorganic phosphate (Pi) starvation by inducing the Pho regulon controlled by PhoB. This activates the phosphate-specific transport (Pst) system that contains a high-affinity Pi transporter. In the Δpst mutant, PhoB is constitutively activated and regulates the expression of genes in the Pho regulon. Here, we show that Pi starvation and deletion of the pst system enhance E. coli O157:H7 biofilm formation. Among differentially expressed genes of EDL933 grown under Pi starvation conditions and in the Δpst mutant, we have found that a member of the PhoB regulon, waaH, predicted to encode a glycosyltransferase, was highly expressed. Interestingly, WaaH contributed to biofilm formation of E. coli O157:H7 during both Pi starvation and in the Δpst mutant. In the Δpst mutant, the presence of waaH was associated with lipopolysaccharide (LPS) R3 core type modifications, whereas in E. coli O157:H7, waaH overexpression had no effect on LPS structure during Pi starvation. Therefore, waaH participates in E. coli O157:H7 biofilm formation during Pi starvation, but its biochemical role remains to be clarified. This study highlights the importance of the Pi starvation stress response to biofilm formation, which may contribute to the persistence of E. coli O157:H7 in the environment.IMPORTANCE Enterohemorrhagic Escherichia coli O157:H7 is a human pathogen that causes bloody diarrhea that can result in renal failure. Outside of mammalian hosts, E. coli O157:H7 survives for extended periods of time in nutrient-poor environments, likely as part of biofilms. In E. coli K-12, the levels of free extracellular Pi affect biofilm formation; however, it was unknown whether Pi influences biofilm formation by E. coli O157:H7. Our results show that upon Pi starvation, PhoB activates waaH expression, which favors biofilm formation by E. coli O157:H7. These findings suggest that WaaH is a target for controlling biofilm formation. Altogether, our work demonstrates how adaptation to Pi starvation allows E. coli O157:H7 to occupy different ecological niches.},
}
@article {pmid31261752,
year = {2019},
author = {Riau, AK and Aung, TT and Setiawan, M and Yang, L and Yam, GHF and Beuerman, RW and Venkatraman, SS and Mehta, JS},
title = {Surface Immobilization of Nano-Silver on Polymeric Medical Devices to Prevent Bacterial Biofilm Formation.},
journal = {Pathogens (Basel, Switzerland)},
volume = {8},
number = {3},
pages = {},
doi = {10.3390/pathogens8030093},
pmid = {31261752},
issn = {2076-0817},
support = {KPFA/2018/0028//Duke-NUS Khoo Postdoctoral Fellowship Award grant/ ; (SHF/FG661P/2017)//SingHealth Foundation grant/ ; },
abstract = {: Bacterial biofilm on medical devices is difficult to eradicate. Many have capitalized the anti-infective capability of silver ions (Ag+) by incorporating nano-silver (nAg) in a biodegradable coating, which is then laid on polymeric medical devices. However, such coating can be subjected to premature dissolution, particularly in harsh diseased tissue microenvironment, leading to rapid nAg clearance. It stands to reason that impregnating nAg directly onto the device, at the surface, is a more ideal solution. We tested this concept for a corneal prosthesis by immobilizing nAg and nano-hydroxyapatite (nHAp) on poly(methyl methacrylate), and tested its biocompatibility with human stromal cells and antimicrobial performance against biofilm-forming pathogens, Pseudomonas aeruginosa and Staphylococcus aureus. Three different dual-functionalized substrates-high Ag (referred to as 75:25 HAp:Ag); intermediate Ag (95:5 HAp:Ag); and low Ag (99:1 HAp:Ag) were studied. The 75:25 HAp:Ag was effective in inhibiting biofilm formation, but was cytotoxic. The 95:5 HAp:Ag showed the best selectivity among the three substrates; it prevented biofilm formation of both pathogens and had excellent biocompatibility. The coating was also effective in eliminating non-adherent bacteria in the culture media. However, a 28-day incubation in artificial tear fluid revealed a ~40% reduction in Ag+ release, compared to freshly-coated substrates. The reduction affected the inhibition of S. aureus growth, but not the P. aeruginosa. Our findings suggest that Ag+ released from surface-immobilized nAg diminishes over time and becomes less effective in suppressing biofilm formation of Gram-positive bacteria, such as S. aureus. This advocates the coating, more as a protection against perioperative and early postoperative infections, and less as a long-term preventive solution.},
}
@article {pmid31261727,
year = {2019},
author = {Chew, SY and Ho, KL and Cheah, YK and Sandai, D and Brown, AJP and Than, LTL},
title = {Physiologically Relevant Alternative Carbon Sources Modulate Biofilm Formation, Cell Wall Architecture, and the Stress and Antifungal Resistance of Candida glabrata.},
journal = {International journal of molecular sciences},
volume = {20},
number = {13},
pages = {},
doi = {10.3390/ijms20133172},
pmid = {31261727},
issn = {1422-0067},
support = {/WT_/Wellcome Trust/United Kingdom ; 01-01-14-1456FR//Ministry of Education, Malaysia/ ; },
abstract = {Flexibility in carbon metabolism is pivotal for the survival and propagation of many human fungal pathogens within host niches. Indeed, flexible carbon assimilation enhances pathogenicity and affects the immunogenicity of Candida albicans. Over the last decade, Candida glabrata has emerged as one of the most common and problematic causes of invasive candidiasis. Despite this, the links between carbon metabolism, fitness, and pathogenicity in C. glabrata are largely unexplored. Therefore, this study has investigated the impact of alternative carbon metabolism on the fitness and pathogenic attributes of C. glabrata. We confirm our previous observation that growth on carbon sources other than glucose, namely acetate, lactate, ethanol, or oleate, attenuates both the planktonic and biofilm growth of C. glabrata, but that biofilms are not significantly affected by growth on glycerol. We extend this by showing that C. glabrata cells grown on these alternative carbon sources undergo cell wall remodeling, which reduces the thickness of their β-glucan and chitin inner layer while increasing their outer mannan layer. Furthermore, alternative carbon sources modulated the oxidative stress resistance of C. glabrata as well as the resistance of C. glabrata to an antifungal drug. In short, key fitness and pathogenic attributes of C. glabrata are shown to be dependent on carbon source. This reaffirms the perspective that the nature of the carbon sources available within specific host niches is crucial for C. glabrata pathogenicity during infection.},
}
@article {pmid31260476,
year = {2019},
author = {Marini, E and Di Giulio, M and Ginestra, G and Magi, G and Di Lodovico, S and Marino, A and Facinelli, B and Cellini, L and Nostro, A},
title = {Efficacy of carvacrol against resistant rapidly growing mycobacteria in the planktonic and biofilm growth mode.},
journal = {PloS one},
volume = {14},
number = {7},
pages = {e0219038},
doi = {10.1371/journal.pone.0219038},
pmid = {31260476},
issn = {1932-6203},
abstract = {Rapidly growing mycobacteria (RGM) are environmental bacteria found worldwide with a propensity to produce skin and soft-tissue infections. Among them, the most clinically relevant species is Mycobacterium abscessus. Multiple resistance to antibiotics and the ability to form biofilm contributes considerably to the treatment failure. The search of novel anti-mycobacterial agents for the control of biofilm growth mode is crucial. The aim of the present study was to evaluate the activity of carvacrol (CAR) against planktonic and biofilm cells of resistant RGM strains. The susceptibility of RGM strains (n = 11) to antibiotics and CAR was assessed by MIC/MBC evaluation. The CAR activity was estimated by also vapour contact assay. The effect on biofilm formation and preformed biofilm was measured by evaluation of bacterial growth, biofilm biomass and biofilm metabolic activity. MIC values were equal to 64 μg/mL for most of RGM isolates (32-512 μg/mL), MBCs were 2-4 times higher than MICs, and MICs of vapours were lower (16 μg/mL for most RGM isolates) than MICs in liquid phase. Regarding the biofilm, CAR at concentrations of 1/2 × MIC and 1/4 × MIC showed a strong inhibition of biofilm formation (61-77%) and at concentration above the MIC (2-8 × MIC) produced significant inhibition of 4- and 8-day preformed biofilms. In conclusion, CAR could have a potential use, also in vapour phase, for the control of RGM.},
}
@article {pmid31260250,
year = {2019},
author = {Simcox, LJ and Pereira, RPA and Wellington, EMH and Macpherson, JV},
title = {Boron Doped Diamond as a Low Biofouling Material in Aquatic Environments: Assessment of Pseudomonas aeruginosa Biofilm Formation.},
journal = {ACS applied materials &amp; interfaces},
volume = {11},
number = {28},
pages = {25024-25033},
doi = {10.1021/acsami.9b07245},
pmid = {31260250},
issn = {1944-8252},
abstract = {Boron doped diamond (BDD), given the robustness of the material, is becoming an electrode of choice for applications which require long-term electrochemical monitoring of analytes in aqueous environments. However, despite the extensive work in this area, there are no studies which directly assess the biofilm formation (biofouling) capabilities of the material, which is an essential consideration because biofouling often causes deterioration in the sensor performance. Pseudomonas aeruginosa is one of the most prevalent bacterial pathogens linked to water-related diseases, with a strong capacity for forming biofilms on surfaces that are exposed to aquatic environments. In this study, we comparatively evaluate the biofouling capabilities of oxygen-terminated (O-)BDD against materials commonly employed as either the packaging or sensing element in water quality sensors, with an aim to identify factors which control biofilm formation on BDD. We assess the monospecies biofilm formation of P. aeruginosa in two different growth media, Luria-Bertani, a high nutrient source and drinking water, a low nutrient source, at two different temperatures (20 and 37 °C). Multispecies biofilm formation is also investigated. The performance of O-BDD, when tested against all other materials, promotes the lowest extent of P. aeruginosa monospecies biofilm formation, even with corrections made for total surface area (roughness). Importantly, O-BDD shows the lowest water contact angle of all materials tested, that is, greatest hydrophilicity, strongly suggesting that for these bacterial species, the factors controlling the hydrophilicity of the surface are important in reducing bacterial adhesion. This was further proven by keeping the surface topography fixed and changing surface termination to hydrogen (H-), to produce a strongly hydrophobic surface. A noticeable increase in biofilm formation was found. Doping with boron also results in changes in hydrophobicity/hydrophilicity compared to the undoped counterpart, which in turn affects the bacterial growth. For practical electrochemical sensing applications in aquatic environments, this study highlights the extremely beneficial effects of employing smooth, O-terminated (hydrophilic) BDD electrodes.},
}
@article {pmid31259174,
year = {2019},
author = {Santos, T and Viala, D and Chambon, C and Esbelin, J and Hébraud, M},
title = {Listeria monocytogenes Biofilm Adaptation to Different Temperatures Seen Through Shotgun Proteomics.},
journal = {Frontiers in nutrition},
volume = {6},
number = {},
pages = {89},
doi = {10.3389/fnut.2019.00089},
pmid = {31259174},
issn = {2296-861X},
abstract = {Listeria monocytogenes is a foodborne pathogen that can cause invasive severe human illness (listeriosis) in susceptible patients. Most human listeriosis cases appear to be caused by consumption of refrigerated ready-to-eat foods. Although initial contamination levels in foods are usually low, the ability of these bacteria to survive and multiply at low temperatures allows it to reach levels high enough to cause disease. This study explores the set of proteins that might have an association with L. monocytogenes adaptation to different temperatures. Cultures were grown in biofilm, the most widespread mode of growth in natural and industrial realms. Protein extractions were performed from three different growth temperatures (10, 25, and 37°C) and two growth phases (early stage and mature biofilm). L. monocytogenes subproteomes were targeted using three extraction methods: trypsin-enzymatic shaving, biotin-labeling and cell fractionation. The different subproteomes obtained were separated and analyzed by shotgun proteomics using high-performance liquid chromatography combined with tandem mass spectrometry (LC-OrbiTrap LTQVelos, ThermoFisher Scientific). A total of 141 (biotinylation), 98 (shaving) and 910 (fractionation) proteins were identified. Throughout the 920 unique proteins identified, many are connected to basic cell functions, but some are linked with thermoregulation. We observed some noteworthy protein abundance shifts associated with the major adaptation to cold mechanisms present in L. monocytogenes, namely: the role of ribosomes and the stressosome with a higher abundance of the general stress protein Ctc (Rl25) and the general stress transcription factor sigma B (σB), changes in cell fluidity and motility seen by higher levels of foldase protein PrsA2 and flagellin (FlaA), the uptake of osmolytes with a higher abundance of glycine betaine (GbuB) and carnitine transporters (OpucA), and the relevance of the overexpression of chaperone proteins such as cold shock proteins (CspLA and Dps). As for 37°C, we observed a significantly higher percentage of proteins associated with transcriptional or translational activity present in higher abundance upon comparison with the colder settings. These contrasts of protein expression throughout several conditions will enrich databases and help to model the regulatory circuitry that drives adaptation of L. monocytogenes to environments.},
}
@article {pmid31254829,
year = {2019},
author = {Barreiro, P and González, P and Pozo-Antonio, JS},
title = {IR irradiation to remove a sub-aerial biofilm from granitic stones using two different laser systems: An Nd: YAG (1064 nm) and an Er:YAG (2940 nm).},
journal = {The Science of the total environment},
volume = {688},
number = {},
pages = {632-641},
doi = {10.1016/j.scitotenv.2019.06.306},
pmid = {31254829},
issn = {1879-1026},
abstract = {A sub-aerial biofilm (SAB) developed on a granite commonly found in the built cultural heritage of the NW Iberian Peninsula was extracted with 2 different IR irradiations using an Nd:YAG laser at 1064 nm and an Er:YAG laser at 2940 nm. The methodology was based on the application of only one scan in order to evaluate the effect of the laser cleaning operated by applying different consecutive laser scanning and the suitability of these lasers as quick tools. The aim of this comparative study was twofold. The first goal was to find the most satisfactory level of extraction by comparing the results obtained by the different laser sources (IR wavelengths). The other aim was to investigate the by-effects induced by both lasers on each granite-forming mineral. Evaluations were made using stereomicroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and scanning electron microscopy with energy-dispersive x-ray spectroscopy. The results were interpreted in terms of SAB extraction and damage induced on the granite. The results showed that the Nd:YAG laser achieved the most successful level of cleaning, because it extracted the most SAB, while causing the least amount of damage to the surfaces. Regardless of the fluence applied, the Er:YAG laser did not completely extract the SAB in only one scan; in addition, a more intense melting of biotite grains was found, producing amorphous fusion crusts and losing the distinction of the cleavage planes.},
}
@article {pmid31254346,
year = {2019},
author = {Gonçalves, B and Azevedo, NM and Henriques, M and Silva, S},
title = {Hormones modulate Candida vaginal isolates biofilm formation and decrease their susceptibility to azoles and hydrogen peroxide.},
journal = {Medical mycology},
volume = {},
number = {},
pages = {},
doi = {10.1093/mmy/myz070},
pmid = {31254346},
issn = {1460-2709},
abstract = {Vulvovaginal candidiasis (VVC) is an infection usually caused by Candida albicans and increasingly by Candida glabrata, which has an intrinsically high resistance to commonly used antifungals. Candida species possess virulence factors that contribute to VVC development, as the ability to form biofilms in vaginal walls and intrauterine devices. It is known that VVC is promoted by conditions that increase the hormones levels, during pregnancy, however, the effects of hormones on Candida cells are poorly studied, especially in C. glabrata. Thus, the influence of progesterone and β-estradiol, at normal cycle and pregnancy concentrations, on biofilm formation and resistance of C. albicans and C. glabrata vaginal isolates, was analyzed using acidic conditions (pH 4). Biofilms of C. albicans developed in the presence of hormones presented reduced biomass (up to 65%) and impaired cells ability to produce filamentous forms. On the other hand, C. glabrata presented high adaptation to the presence of hormones, which did not affect its biofilm formation. Additionally, hormones impaired the susceptibility of C. albicans and C. glabrata cells to azoles, with potential clinical significance in the presence of pregnancy hormone levels. A similar result was obtained for the susceptibility to hydrogen peroxide, a biological vaginal barrier against Candida growth. Overall, the results of this study suggest that hormones may act as environmental cues promoting Candida protection from vaginal defenses and harmful conditions, what may have implications in Candida vaginal pathogenicity and treatment of VVC, especially in C. glabrata infections due to its high adaptability to vaginal conditions.},
}
@article {pmid31253082,
year = {2019},
author = {Suryaletha, K and Narendrakumar, L and John, J and Radhakrishnan, MP and George, S and Thomas, S},
title = {Decoding the proteomic changes involved in the biofilm formation of Enterococcus faecalis SK460 to elucidate potential biofilm determinants.},
journal = {BMC microbiology},
volume = {19},
number = {1},
pages = {146},
doi = {10.1186/s12866-019-1527-2},
pmid = {31253082},
issn = {1471-2180},
support = {BT/PR15261/MED/29/994/2015//Department of Biotechnology, Govt. of India/ ; },
abstract = {BACKGROUND: Enterococcus faecalis is a major clinically relevant nosocomial bacterial pathogen frequently isolated from polymicrobial infections. The biofilm forming ability of E. faecalis attributes a key role in its virulence and drug resistance. Biofilm cells are phenotypically and metabolically different from their planktonic counterparts and many aspects involved in E. faecalis biofilm formation are yet to be elucidated. The strain E. faecalis SK460 used in the present study is esp (Enterococcal surface protein) and fsr (two-component signal transduction system) negative non-gelatinase producing strong biofilm former isolated from a chronic diabetic foot ulcer patient. We executed a label-free quantitative proteomic approach to elucidate the differential protein expression pattern at planktonic and biofilm stages of SK460 to come up with potential determinants associated with Enterococcal biofilm formation.<br><br>RESULTS: The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of proteomic data revealed that biofilm cells expressed higher levels of proteins which are associated with glycolysis, amino acid biosynthesis, biosynthesis of secondary metabolites, microbial metabolism in diverse environments and stress response factors. Besides these basic survival pathways, LuxS-mediated quorum sensing, arginine metabolism, rhamnose biosynthesis, pheromone and adhesion associated proteins were found to be upregulated during the biofilm transit from planktonic stages. The selected subsets were validated by quantitative real-time PCR. In silico functional interaction analysis revealed that the genes involved in upregulated pathways pose a close molecular interaction thereby coordinating the regulatory network to thrive as a biofilm community.<br><br>CONCLUSIONS: The present study describes the first report of the quantitative proteome analysis of an esp and fsr negative non gelatinase producing E. faecalis. Proteome analysis evidenced enhanced expression of glycolytic pathways, stress response factors, LuxS quorum signaling system, rhamnopolysaccharide synthesis and pheromone associated proteins in biofilm phenotype. We also pointed out the relevance of LuxS quorum sensing and pheromone associated proteins in the biofilm development of E. faecalis which lacks the Fsr quorum signaling system. These validated biofilm determinants can act as potential inhibiting targets in Enterococcal infections.},
}
@article {pmid31252357,
year = {2019},
author = {Shi, LD and Wang, M and Li, ZY and Lai, CY and Zhao, HP},
title = {Dissolved oxygen has no inhibition on methane oxidation coupled to selenate reduction in a membrane biofilm reactor.},
journal = {Chemosphere},
volume = {234},
number = {},
pages = {855-863},
doi = {10.1016/j.chemosphere.2019.06.138},
pmid = {31252357},
issn = {1879-1298},
abstract = {Methane oxidation coupled to selenate reduction has been suggested as a promising technology to bio-remediate selenium contaminated environments. However, the effect of dissolved oxygen (DO) on this process remained unclear. Here, we investigate the feasibility of selenate removal at two distinct DO concentrations. A membrane biofilm reactor (MBfR) was initially fed with ∼5 mg Se/L and then lowered to ∼1 mg Se/L of selenate, under anoxic condition containing ∼0.2 mg/L of influent DO. Selenate removal reached approximately 90% without selenite accumulation after one-month operation. Then 6-7 mg/L of DO was introduced and showed no apparent effect on selenate reduction in the subsequent operation. Electron microscopy suggested elevated oxygen exposure did not affect microbial shapes. 16S rDNA sequencing showed the aerobic methanotroph Methylocystis increased, while possible selenate reducers, Ignavibacterium and Bradyrhizobium, maintained stable after oxygen boost. Gene analysis indicated that nitrate/nitrite reductases positively correlated with selenate removal flux and were not remarkably affected by oxygen addition. Reversely, enzymes related with aerobic methane oxidation were obviously improved. This study provides a potential technology for selenate removal from oxygenated environments in a methane-based MBfR.},
}
@article {pmid31251598,
year = {2019},
author = {Jack, AA and Nordli, HR and Powell, LC and Farnell, DJJ and Pukstad, B and Rye, PD and Thomas, DW and Chinga-Carrasco, G and Hill, KE},
title = {Cellulose Nanofibril Formulations Incorporating a Low-Molecular-Weight Alginate Oligosaccharide Modify Bacterial Biofilm Development.},
journal = {Biomacromolecules},
volume = {20},
number = {8},
pages = {2953-2961},
doi = {10.1021/acs.biomac.9b00522},
pmid = {31251598},
issn = {1526-4602},
abstract = {Cellulose nanofibrils (CNFs) from wood pulp are a renewable material possessing advantages for biomedical applications because of their customizable porosity, mechanical strength, translucency, and environmental biodegradability. Here, we investigated the growth of multispecies wound biofilms on CNF formulated as aerogels and films incorporating the low-molecular-weight alginate oligosaccharide OligoG CF-5/20 to evaluate their structural and antimicrobial properties. Overnight microbial cultures were adjusted to 2.8 × 109 colony-forming units (cfu) mL-1 in Mueller Hinton broth and growth rates of Pseudomonas aeruginosa PAO1 and Staphylococcus aureus 1061A monitored for 24 h in CNF dispersions sterilized by γ-irradiation. Two CNF formulations were prepared (20 g m-2) with CNF as air-dried films or freeze-dried aerogels, with or without incorporation of an antimicrobial alginate oligosaccharide (OligoG CF-5/20) as a surface coating or bionanocomposite, respectively. The materials were structurally characterized by scanning electron microscopy (SEM) and laser profilometry (LP). The antimicrobial properties of the formulations were assessed using single- and mixed-species biofilms grown on the materials and analyzed using LIVE/DEAD staining with confocal laser scanning microscopy (CLSM) and COMSTAT software. OligoG-CNF suspensions significantly decreased the growth of both bacterial strains at OligoG concentrations >2.58% (P < 0.05). SEM showed that aerogel-OligoG bionanocomposite formulations had a more open three-dimensional structure, whereas LP showed that film formulations coated with OligoG were significantly smoother than untreated films or films incorporating PEG400 as a plasticizer (P < 0.05). CLSM of biofilms grown on films incorporating OligoG demonstrated altered biofilm architecture, with reduced biomass and decreased cell viability. The OligoG-CNF formulations as aerogels or films both inhibited pyocyanin production (P < 0.05). These novel CNF formulations or bionanocomposites were able to modify bacterial growth, biofilm development, and virulence factor production in vitro. These data support the potential of OligoG and CNF bionanocomposites for use in biomedical applications where prevention of infection or biofilm growth is required.},
}
@article {pmid31251015,
year = {2019},
author = {Ng, CK and Karahan, HE and Loo, SCJ and Chen, Y and Cao, B},
title = {Biofilm-Templated Heteroatom-Doped Carbon-Palladium Nanocomposite Catalyst for Hexavalent Chromium Reduction.},
journal = {ACS applied materials &amp; interfaces},
volume = {11},
number = {27},
pages = {24018-24026},
doi = {10.1021/acsami.9b04095},
pmid = {31251015},
issn = {1944-8252},
abstract = {In this study, we report an interdisciplinary and novel strategy toward biofilm engineering for the development of a biofilm-templated heteroatom-doped catalytic system through bioreduction and biofilm matrix-facilitated immobilization of the in situ-formed catalytic nanoparticles followed by controlled pyrolysis. We showed that (i) even under room temperature and bulk aerobic conditions, Shewanella oneidensis MR-1 biofilms reduced Pd(II) to form Pd(0) nanocrystals (∼10 to 20 nm) that were immobilized in the biofilm matrix and in cellular membranes, (ii) the MR-1 biofilms with the immobilized Pd(0) nanocrystals exhibited nanocatalytic activity, (iii) exposure to Pd(II) greatly increased the rate of cell detachment from the biofilm and posed a risk of biofilm dispersal, (iv) controlled pyrolysis (carbonization) of the biofilm led to the formation of a stable heteroatom-doped carbon-palladium (C-Pd) nanocomposite catalyst, and (v) the biofilm-templated C-Pd nanocomposite catalyst exhibited a high Cr(VI) reduction activity and maintained a high reduction rate over multiple catalytic cycles. Considering that bacteria are capable of synthesizing a wide range of metal and metalloid nanoparticles, the biofilm-templated approach for the fabrication of the catalytic C-Pd nanocomposite we have demonstrated here should prove to be widely applicable for the production of different nanocomposites that are of importance to various environmental applications.},
}
@article {pmid31250405,
year = {2019},
author = {Pham, DTN and Khan, F and Phan, TTV and Park, SK and Manivasagan, P and Oh, J and Kim, YM},
title = {Biofilm inhibition, modulation of virulence and motility properties by FeOOH nanoparticle in Pseudomonas aeruginosa.},
journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]},
volume = {50},
number = {3},
pages = {791-805},
doi = {10.1007/s42770-019-00108-z},
pmid = {31250405},
issn = {1678-4405},
support = {20150220//Ministry of Education/ ; },
abstract = {Biofilm formation is one of the resistance mechanisms of Pseudomonas aeruginosa against antimicrobial compounds. Biofilm formation also characterizes for the infection and pathogenesis of P. aeruginosa, along with production of various virulence factors. With recent development of nanotechnology, the present study aims to employ the synthetic iron nanoparticle (FeOOH-NP) as an active agent to inhibit the formation of P. aeruginosa biofilm. The FeOOH-NP was synthesized and characterized with rod shape and average size of 40 nm. Inhibition of biofilm formation by the FeOOH-NP is in a concentration-dependent manner, with inhibition of biofilm formation increased as the FeOOH-NP concentration increased. Microscopic observations also confirmed the disruption of the biofilm architecture in the presence of the FeOOH-NP. In addition, the presence of the FeOOH-NP was also found to modulate bacterial motility as well as some other important virulence factors produced simultaneously with biofilm formation. These findings provide insights to anti-biofilm effect of a new iron NP, contributing to the search for an effective agent to combat P. aeruginosa infections resulted from biofilm formation.},
}
@article {pmid31250387,
year = {2019},
author = {Fallatah, H and Elhaneid, M and Ali-Boucetta, H and Overton, TW and El Kadri, H and Gkatzionis, K},
title = {Antibacterial effect of graphene oxide (GO) nano-particles against Pseudomonas putida biofilm of variable age.},
journal = {Environmental science and pollution research international},
volume = {26},
number = {24},
pages = {25057-25070},
doi = {10.1007/s11356-019-05688-9},
pmid = {31250387},
issn = {1614-7499},
abstract = {Graphene oxide (GO) has been reported to possess antibacterial activity; therefore, its accumulation in the environment could affect microbial communities such as biofilms. The susceptibility of biofilms to antimicrobials is known to depend on the stage of biofilm maturity. The aim of this study was to investigate the effect of GO nano-particles on Pseudomonas putida KT2440 biofilm of variable age. FT-IR, UV-vis, and Raman spectroscopy confirmed the oxidation of graphene while XPS confirmed the high purity of the synthesised GO over 6 months. Biofilms varying in maturity (24, 48, and 72 h) were formed using a CDC reactor and were treated with GO (85 μg/mL or 8.5 μg/mL). The viability of P. putida was monitored by culture on media and the bacterial membrane integrity was assessed using flow cytometry. P. putida cells were observed using confocal microscopy and SEM. The results showed that GO significantly reduced the viability of 48-h biofilm and detached biofilm cells associated with membrane damage while the viability was not affected in 24- and 72-h biofilms and detached biofilm cells. The results showed that susceptibility of P. putida biofilm to GO varied according to age which may be due to changes in the physiological state of cells during maturation. Graphical abstract.},
}
@article {pmid31250076,
year = {2019},
author = {Jeong, SY and Lee, CH and Yi, T and Kim, TG},
title = {Effects of Quorum Quenching on Biofilm Metacommunity in a Membrane Bioreactor.},
journal = {Microbial ecology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00248-019-01397-5},
pmid = {31250076},
issn = {1432-184X},
support = {2018R1D1A1B07048872//Ministry of Education/ ; },
abstract = {Quorum quenching (QQ) has received attention for the control of biofilms, e.g., biofilms that cause biofouling in membrane bioreactors (MBRs). Despite the efficacy of QQ on biofouling, it is elusive how QQ influences biofilm formation on membranes. A pilot-scale QQ-MBR and non-QQ-MBR were identically operated for 4 days and 8 days to destructively sample the membranes. QQ prolonged the membrane filterability by 43% with no harmful influence on MBR performance. qPCR showed no effect of QQ on microbial density during either of these time periods. Community comparisons revealed that QQ influenced the bacterial and fungal community structures, and the fungal structure corresponded with the bacterial structure. Metacommunity and spatial analyses showed that QQ induced structural variation rather than compositional variation of bacteria and fungi. Moreover, QQ considerably enhanced the bacterial dispersal across membrane during the early development. As the dispersal enhancement by QQ counteracted the ecological drift, it eliminated the distance-decay relationship, reflecting a neutral theory archetype of metacommunity. Network analyses showed that QQ substantially reduced the amount and magnitude of interactions, e.g., competition and cooperation, for bacteria and fungi, and weakened their network structures, irrespective of time. Additionally, QQ suppressed the growth of specific microbial species (e.g., Acinetobacter), abundant and widespread at the early stage. These findings suggest that QQ influenced the community dynamics at the regional and local levels, correspondingly the ecological selection and dispersal processes, during the biofilm development.},
}
@article {pmid31246756,
year = {2019},
author = {Jewell, ML and Fickas, B and Jewell, H and Jewell, ML},
title = {Implant Surface Options and Biofilm Mitigation Strategies.},
journal = {Plastic and reconstructive surgery},
volume = {144},
number = {1S Utilizing a Spectrum of Cohesive Implants in Aesthetic and Reconstructive Breast Surgery},
pages = {13S-20S},
doi = {10.1097/PRS.0000000000005946},
pmid = {31246756},
issn = {1529-4242},
abstract = {Two important topics in breast augmentation and reconstruction relate to device surface texture and practices to mitigate biofilm contamination of implants. Breast augmentation can be considered a manufacturing process where planning concepts of process engineering and quality can be used to produce great outcomes. This article reviews the options available for surgeons with regards to device surface texture selection and practices to mitigate biofilm contamination of implants at the time of surgery.},
}
@article {pmid31246167,
year = {2019},
author = {Pal, S and Verma, J and Mallick, S and Rastogi, SK and Kumar, A and Ghosh, AS},
title = {Absence of the glycosyltransferase WcaJ in Klebsiella pneumoniae ATCC13883 affects biofilm formation, increases polymyxin resistance and reduces murine macrophage activation.},
journal = {Microbiology (Reading, England)},
volume = {165},
number = {8},
pages = {891-904},
doi = {10.1099/mic.0.000827},
pmid = {31246167},
issn = {1465-2080},
abstract = {Multidrug-resistant Klebsiella pneumoniae has emerged as one of the deadliest opportunistic nosocomial pathogens that forms biofilm for the establishment of chronic K. pneumoniae infections. Herein, we made an attempt to identify the genes involved in biofilm formation in the strain K. pneumoniae ATCC13883. To achieve this, we constructed mini-Tn5 transposon insertion mutants and screened them for biofilm production. We observed that the biofilm formation was enhanced in the mutant where the wcaJ gene was disrupted. WcaJ is the initiating enzyme of colanic acid synthesis and loads the first sugar (glucose-1-P) on the lipid carrier undecaprenyl phosphate. The absence of this glycosyltransferase results in the absence of colanic acid, which renders a non-mucoid phenotype to the mutant. Further, to determine the effect of mucoidy on antibiotic susceptibility, we tested the sensitivity of the strains towards different groups of antibiotics. Unlike the mucoid strains, the resistance of the non-mucoid cells was greater for polymyxins, but less for quinolones. Capsular polysaccharides are known to have a protective effect against phagocytosis, therefore we assessed the role of colanic acid in virulence by conducting infection studies on murine macrophages. Surprisingly, the ΔwcaJ strain was less efficient in macrophage activation and was not readily phagocytosed. Thus, the presence of colanic acid appeared to increase the immunogenicity of K. pneumoniae. Overall, the results indicate that the presence of colanic acid increases the vulnerability of K. pneumoniae towards both polymyxins and macrophages, implying that the mucoid strains are less threatening as compared to their high biofilm forming non-mucoid counterparts.},
}
@article {pmid31244785,
year = {2019},
author = {Zeng, S and Constant, P and Yang, D and Baulard, A and Lefèvre, P and Daffé, M and Wattiez, R and Fontaine, V},
title = {Cpn60.1 (GroEL1) Contributes to Mycobacterial Crabtree Effect: Implications for Biofilm Formation.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1149},
doi = {10.3389/fmicb.2019.01149},
pmid = {31244785},
issn = {1664-302X},
abstract = {Biofilm formation is a survival strategy for microorganisms facing a hostile environment. Under biofilm, bacteria are better protected against antibacterial drugs and the immune response, increasing treatment difficulty, as persistent populations recalcitrant to chemotherapy are promoted. Deciphering mechanisms leading to biofilms could, thus, be beneficial to obtain new antibacterial drug candidates. Here, we show that mycobacterial biofilm formation is linked to excess glycerol adaptation and the concomitant establishment of the Crabtree effect. This effect is characterized by respiratory reprogramming, ATP downregulation, and secretion of various metabolites including pyruvate, acetate, succinate, and glutamate. Interestingly, the Crabtree effect was abnormal in a mycobacterial strain deficient for Cpn60.1 (GroEL1). Indeed, this mutant strain had a compromised ability to downregulate ATP and secreted more pyruvate, acetate, succinate, and glutamate in the culture medium. Importantly, the mutant strain had higher intracellular pyruvate and produced more toxic methylglyoxal, suggesting a glycolytic stress leading to growth stasis and consequently biofilm failure. This study demonstrates, for the first time, the link between mycobacterial biofilm formation and the Crabtree effect.},
}
@article {pmid31241174,
year = {2019},
author = {Tang, Y and Zhang, Z and Rittmann, BE and Lee, HS},
title = {Kinetics of anaerobic methane oxidation coupled to denitrification in the membrane biofilm reactor.},
journal = {Biotechnology and bioengineering},
volume = {116},
number = {10},
pages = {2550-2560},
doi = {10.1002/bit.27098},
pmid = {31241174},
issn = {1097-0290},
support = {//Florida State University/ ; STPGP 478972//Natural Sciences and Engineering Research Council of Canada/ ; },
abstract = {Anaerobic oxidation of methane coupled to denitrification (AOM-D) in a membrane biofilm reactor (MBfR), a platform used for efficiently coupling gas delivery and biofilm development, has attracted attention in recent years due to the low cost and high availability of methane. However, experimental studies have shown that the nitrate-removal flux in the CH4 -based MBfR (<1.0 g N/m2 -day) is about one order of magnitude smaller than that in the H2 -based MBfR (1.1-6.7 g N/m2 -day). A one-dimensional multispecies biofilm model predicts that the nitrate-removal flux in the CH4 -based MBfR is limited to <1.7 g N/m2 -day, consistent with the experimental studies reported in the literature. The model also determines the two major limiting factors for the nitrate-removal flux: The methane half-maximum-rate concentration (K2) and the specific maximum methane utilization rate of the AOM-D syntrophic consortium (kmax2), with kmax2 being more important. Model simulations show that increasing kmax2 to >3 g chemical oxygen demand (COD)/g cell-day (from its current 1.8 g COD/g cell-day) and developing a new membrane with doubled methane-delivery capacity (Dm) could bring the nitrate-removal flux to ≥4.0 g N/m2 -day, which is close to the nitrate-removal flux for the H2 -based MBfR. Further increase of the maximum nitrate-removal flux can be achieved when Dm and kmax2 increase together.},
}
@article {pmid31239789,
year = {2019},
author = {Nuryastuti, T and Umaroh, N and Asdie, RH and Sari, IP and Musthafa, A},
title = {Pan-drug-resistant and biofilm-producing strain of Burkholderia pseudomallei: first report of melioidosis from a diabetic patient in Yogyakarta, Indonesia [Response to Letter].},
journal = {International medical case reports journal},
volume = {12},
number = {},
pages = {171-172},
doi = {10.2147/IMCRJ.S213150},
pmid = {31239789},
issn = {1179-142X},
}
@article {pmid31239382,
year = {2019},
author = {Kavanaugh, JS and Flack, CE and Lister, J and Ricker, EB and Ibberson, CB and Jenul, C and Moormeier, DE and Delmain, EA and Bayles, KW and Horswill, AR},
title = {Identification of Extracellular DNA-Binding Proteins in the Biofilm Matrix.},
journal = {mBio},
volume = {10},
number = {3},
pages = {},
doi = {10.1128/mBio.01137-19},
pmid = {31239382},
issn = {2150-7511},
support = {I01 BX002711/BX/BLRD VA/United States ; P01 AI083211/AI/NIAID NIH HHS/United States ; },
abstract = {We developed a new approach that couples Southwestern blotting and mass spectrometry to discover proteins that bind extracellular DNA (eDNA) in bacterial biofilms. Using Staphylococcus aureus as a model pathogen, we identified proteins with known DNA-binding activity and uncovered a series of lipoproteins with previously unrecognized DNA-binding activity. We demonstrated that expression of these lipoproteins results in an eDNA-dependent biofilm enhancement. Additionally, we found that while deletion of lipoproteins had a minimal impact on biofilm accumulation, these lipoprotein mutations increased biofilm porosity, suggesting that lipoproteins and their associated interactions contribute to biofilm structure. For one of the lipoproteins, SaeP, we showed that the biofilm phenotype requires the lipoprotein to be anchored to the outside of the cellular membrane, and we further showed that increased SaeP expression correlates with more retention of high-molecular-weight DNA on the bacterial cell surface. SaeP is a known auxiliary protein of the SaeRS system, and we also demonstrated that the levels of SaeP correlate with nuclease production, which can further impact biofilm development. It has been reported that S. aureus biofilms are stabilized by positively charged cytoplasmic proteins that are released into the extracellular environment, where they make favorable electrostatic interactions with the negatively charged cell surface and eDNA. In this work we extend this electrostatic net model to include secreted eDNA-binding proteins and membrane-attached lipoproteins that can function as anchor points between eDNA in the biofilm matrix and the bacterial cell surface.IMPORTANCE Many bacteria are capable of forming biofilms encased in a matrix of self-produced extracellular polymeric substances (EPS) that protects them from chemotherapies and the host defenses. As a result of these inherent resistance mechanisms, bacterial biofilms are extremely difficult to eradicate and are associated with chronic wounds, orthopedic and surgical wound infections, and invasive infections, such as infective endocarditis and osteomyelitis. It is therefore important to understand the nature of the interactions between the bacterial cell surface and EPS that stabilize biofilms. Extracellular DNA (eDNA) has been recognized as an EPS constituent for many bacterial species and has been shown to be important in promoting biofilm formation. Using Staphylococcus aureus biofilms, we show that membrane-attached lipoproteins can interact with the eDNA in the biofilm matrix and promote biofilm formation, which suggests that lipoproteins are potential targets for novel therapies aimed at disrupting bacterial biofilms.},
}
@article {pmid31236717,
year = {2019},
author = {Cavero-Olguin, VH and Hatti-Kaul, R and Cardenas-Alegria, OV and Gutierrez-Valverde, M and Alfaro-Flores, A and Romero-Calle, DX and Alvarez-Aliaga, MT},
title = {Stress induced biofilm formation in Propionibacterium acidipropionici and use in propionic acid production.},
journal = {World journal of microbiology &amp; biotechnology},
volume = {35},
number = {7},
pages = {101},
doi = {10.1007/s11274-019-2679-9},
pmid = {31236717},
issn = {1573-0972},
support = {2008-00849//VINNOVA/ ; },
mesh = {*Biofilms ; Bioreactors/microbiology ; Cells, Immobilized ; Fermentation ; Gene Expression Regulation ; Genes, Bacterial ; Glycerol/metabolism ; In Situ Hybridization, Fluorescence ; Microscopy, Atomic Force ; Propionates/*metabolism ; Propionibacterium/genetics/*metabolism ; RNA, Ribosomal, 16S/genetics/isolation &amp; purification ; Reverse Transcriptase Polymerase Chain Reaction ; *Stress, Physiological ; Trehalose/metabolism ; },
abstract = {Propionibacterium acidipropionici produces propionic acid from different sugars and glycerol; the production can be improved by high cell density fermentations using immobilized cells that help to overcome the limitations of the non-productive lag phase and product inhibition. In this study, the use of stress factors to induce P. acidipropionici to form biofilm and its use as an immobilization procedure in fermentations in bioreactors for producing propionic acid was investigated. Citric acid and sodium chloride increased exopolysaccharide production, biofilm forming capacity index and trehalose production. Analysis of the expression of trehalose synthesis-related genes otsA and treY by RT-qPCR showed significantly increased expression of only treY during log phase with citric acid, while FISH analysis showed expression of treY and luxS under the influence of both stress factors. The stress factors were then used for development of microbial biofilms as immobilization procedure on Poraver® and AnoxKaldnes® carriers in recycle batch reactors for propionic acid production from 20 g/L glycerol. Highest productivities of 0.7 and 0.78 g/L/h were obtained in Poraver® reactors, and 0.39 and 0.43 g/L/h in AnoxKaldnes® reactors with citric acid and NaCl, respectively.},
}
@article {pmid31235750,
year = {2019},
author = {Costa, ACBP and Omran, RP and Correia-Mesquita, TO and Dumeaux, V and Whiteway, M},
title = {Screening of Candida albicans GRACE library revealed a unique pattern of biofilm formation under repression of the essential gene ILS1.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {9187},
doi = {10.1038/s41598-019-45624-y},
pmid = {31235750},
issn = {2045-2322},
support = {209671//Fonds de Recherche du Qu&amp;#x00E9;bec - Nature et Technologies (Quebec Fund for Research in Nature and Technology)/ ; RGPIN/4799//Canadian Network for Research and Innovation in Machining Technology, Natural Sciences and Engineering Research Council of Canada (NSERC Canadian Network for Research and Innovation in Machining Technology)/ ; 950-228957//Canada Research Chairs (Chaires de recherche du Canada)/ ; },
abstract = {Candida albicans biofilm formation is governed by a regulatory circuit comprising nine transcription factors which control a network of target genes. However, there are still unknown genes contributing to biofilm features. Thus, the GRACE library was screened to identify genes involved in mature biofilm development. Twenty-nine conditional mutants were selected for a second screening revealing three groups of genes: twenty- two conditional mutants were defective for normal growth and unable to form biofilms; six strains, conditionally defective in genes ARC40, ARC35, ORF19.2438, SKP1, ERG6, and ADE5,7 that are likely essential or involved in general cell processes, grew normally as free-floating cells but produced less biofilm; finally, the conditional strain for a putative essential isoleucyl- tRNA synthetase gene, ILS1, was unable to grow as yeast-phase cells but was capable of producing a tridimensional biofilm structure in spite of reduced metabolic activity. This unique biofilm still relied on the classical biofilm genes, while it differentially induced groups of genes involved in adhesion, protein synthesis, cell wall organization, and protein folding. Although the conditional mutant repressed genes annotated for morphology and homeostasis processes affecting morphology and metabolism, the dynamic cell growth enabled the formation of a complex biofilm community independent of ILS1.},
}
@article {pmid31235348,
year = {2019},
author = {Takeuchi, N and Ohkusu, M and Wada, N and Kurosawa, S and Miyabe, A and Yamaguchi, M and Nahm, MH and Ishiwada, N},
title = {Molecular typing, antibiotic susceptibility, and biofilm production in nonencapsulated Streptococcus pneumoniae isolated from children in Japan.},
journal = {Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy},
volume = {25},
number = {10},
pages = {750-757},
doi = {10.1016/j.jiac.2019.02.007},
pmid = {31235348},
issn = {1437-7780},
abstract = {The prevalence of nonencapsulated Streptococcus pneumoniae (NESp) has increased with the introduction of pneumococcal conjugate vaccines in children; however, the bacteriological characteristics of NESp have not been sufficiently clarified. In this study, NESp strains isolated from the nasopharyngeal carriage of children from four nursery schools in Japan were analyzed for molecular type, antibiotic susceptibility, and biofilm productivity. A total of 152 putative S. pneumoniae strains were identified by optochin-susceptibility analysis, of which 21 were not serotypeable by slide agglutination, quellung reaction, or multiplex PCR. Among these 21 strains, three were lytA-negative and, therefore, not S. pneumoniae. The remaining 18 strains were positive for lytA, ply, pspK, and bile solubility and were confirmed as NESp. Therefore, the isolation rate of NESp in the S. pneumoniae strains in this study was 12.0% (18/149). Molecular-typing analyses classified five strains as two existing sequence types (STs; ST7502 and ST7786), and 13 strains formed four novel STs. Horizontal spread was suspected, because strains with the same ST were often isolated from the same nursery school. The NESp isolates were generally susceptible to most antimicrobials, with the exception of macrolides; however, all isolates possessed more than one abnormal penicillin-binding protein gene. Furthermore, NESp strains were more effective than encapsulated counterparts at forming biofilms, which showed obvious differences in morphology. These data indicated that NESp strains should be continuously monitored as emerging respiratory pathogens.},
}
@article {pmid31234908,
year = {2019},
author = {Hagos, DG and Mezgebo, TA and Berhane, S and Medhanyie, AA},
title = {Biofilm and hemagglutinin formation: a Hallmark for drug resistant uropathogenic Escherichia coli.},
journal = {BMC research notes},
volume = {12},
number = {1},
pages = {358},
doi = {10.1186/s13104-019-4382-1},
pmid = {31234908},
issn = {1756-0500},
support = {40//Mekelle University/ ; 000.00 Eth.Birr//Mekelle University/ ; },
abstract = {OBJECTIVE: Urinary tract infection (UTI) is one of the most frequent disease encounters in pregnant mothers, and the most drug resistant, biofilm and hemagglutinin producer Uropathogenic Escherichia coli (UPEC) is the major etiologic agent. Therefore, the aim of this study was to assess the association between the antimicrobial resistance, and biofilm and hemagglutinin production of Uropathogenic Escherichia coli.<br><br>RESULTS: UTI among the study participants was 27.3%; and UPEC was found the major etiologic agent followed by coagulase negative staphylococcus. Risk factors, previous history of catheterization and previous history of UTI were found significantly associated with UTI, recurrent UTI, drug resistance and biofilm formation. Of the tested antibiotics, nitrofurantoin was the most effective drug for UPEC. Nearly 100% of the biofilm producers were resistant to norfloxacin, cotrimoxazole, and gentamicin.},
}
@article {pmid31234765,
year = {2019},
author = {Grishin, AV and Karyagina, AS},
title = {Polysaccharide Galactan Inhibits Pseudomonas aeruginosa Biofilm Formation but Protects Pre-formed Biofilms from Antibiotics.},
journal = {Biochemistry. Biokhimiia},
volume = {84},
number = {5},
pages = {509-519},
doi = {10.1134/S0006297919050055},
pmid = {31234765},
issn = {1608-3040},
mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Galactans/*pharmacology ; Microbial Sensitivity Tests ; Microscopy, Fluorescence ; Pseudomonas aeruginosa/growth &amp; development/*physiology ; Solanum tuberosum/metabolism ; },
abstract = {Microorganisms residing within a biofilm become more tolerant to antibiotics and other types of adverse impact, and biofilm formation by pathogenic bacteria is an important problem of current medicine. Polysaccharides that prevent biofilm formation are among the promising candidates to help tackle this problem. Earlier we demonstrated the ability of a potato polysaccharide galactan to inhibit biofilm formation by a Pseudomonas aeruginosa clinical isolate. Here we investigate the effect of potato galactan on P. aeruginosa biofilms in more detail. Microscopic analysis indicated that the galactan did not interfere with the adhesion of bacterial cells to the substrate but prevented the build-up of bacterial biomass. Moreover, the galactan not only inhibited biofilm formation, but partially destroyed pre-formed biofilms. Presumably, this activity of the galactan was due to the excessive aggregation of bacterial cells, which prohibited the formation and maintenance of proper biofilm architecture, or due to some other mechanisms of biofilm structure remodeling. This led to an unexpected effect, i.e., P. aeruginosa biofilms treated with an antibiotic and the galactan retained more viable bacterial cells compared to biofilms treated with the antibiotic alone. Galactan is the first polysaccharide demonstrated to exert such effect on bacterial biofilms.},
}
@article {pmid31233774,
year = {2019},
author = {Nakamura, H and Shimizu, T and Takatani, A and Suematsu, T and Nakamura, T and Kawakami, A},
title = {Initial human T-cell leukemia virus type 1 infection of the salivary gland epithelial cells requires a biofilm-like structure.},
journal = {Virus research},
volume = {269},
number = {},
pages = {197643},
doi = {10.1016/j.virusres.2019.197643},
pmid = {31233774},
issn = {1872-7492},
abstract = {The initial phase of the human T cell leukemia virus-1 (HTLV-1) infection of salivary gland epithelial cells (SGECs) was examined. SGECs of patients with Sjögren's syndrome (SS) and non-SS subjects were co-cultured with the HTLV-1-infected cell line HCT-5 or MOLT-4, then immunofluorescence (IF), scanning and transmission electron microscopy (SEM/TEM) were employed. The extracellular matrix and linker proteins galectin-3, agrin, and tetherin were expressed on the surfaces of both HCT-5 and MOLT-4 cells. HTLV-1 Gag-positive spots were observed on adjacent SGECs after 1 h of co-culture with HCT-5. Both in subjects with and those without SS, agrin and tetherin were co-expressed with HTLV-1 Gag on SGECs after co-culture with HCT-5, although no polarization of HTLV-1 Gag and relevant molecules was observed. SEM showed HTLV-1 virions that were found on HCT-5 were observed in the interfaces between HCT-5 cells and SGECs. TEM imaging showed that HTLV-1 virions were transmitted to SGECs at the interface with thin film-like structure, while HTLV-1 virions were released from the surface of HCT-5 cells. No endogenous retroviruses were observed. These results showed that the initial phase of HTLV-1 infection toward SGECs of SS was mediated not by viral synapses, but by biofilm-like components.},
}
@article {pmid31233560,
year = {2019},
author = {Mendis, HC and Ozcan, A and Santra, S and De La Fuente, L},
title = {A novel Zn chelate (TSOL) that moves systemically in citrus plants inhibits growth and biofilm formation of bacterial pathogens.},
journal = {PloS one},
volume = {14},
number = {6},
pages = {e0218900},
doi = {10.1371/journal.pone.0218900},
pmid = {31233560},
issn = {1932-6203},
abstract = {Ternary solution (TSOL) is a novel Zn chelate-based systemic antimicrobial formulation designed for treating citrus bacterial pathogens 'Candidatus Liberibacter asiaticus' and Xanthomonas citri subsp. citri. TSOL is a component of MS3T, a novel multifunctional surface/sub-surface/systemic therapeutic formulation. Antimicrobial activity of TSOL was compared with the antimicrobial compound ZnO against X. citri subsp. citri and 'Ca. L. asiaticus' surrogate Liberibacter crescens in batch cultures. X. citri subsp. citri and L. crescens were also introduced into microfluidic chambers, and the inhibitory action of TSOL against biofilm formation was evaluated. The minimum inhibitory concentration of TSOL for both X. citri subsp. citri and L. crescens was 40ppm. TSOL was bactericidal to X. citri subsp. citri and L. crescens above 150 ppm and 200 ppm, respectively. On the contrary, ZnO was more effective as a bactericidal agent against L. crescens than X. citri subsp. citri. TSOL was more effective in controlling growth and biofilm formation of X. citri subsp. citri in batch cultures compared to ZnO. Time-lapse video imaging microscopy showed that biofilm formation of X. citri subsp. citri was inhibited in microfluidic chambers treated with 60 ppm TSOL. TSOL also inhibited further growth of already formed X. citri subsp. citri and L. crescens biofilms in microfluidic chambers. Leaf spraying of TSOL showed higher plant uptake and systemic movement in citrus (Citrus reshni) plants compared to that of ZnO, suggesting that TSOL is a promising antimicrobial compound to control vascular plant pathogens such as 'Ca. L. asiaticus'.},
}
@article {pmid31233528,
year = {2019},
author = {Soler-Arango, J and Figoli, C and Muraca, G and Bosch, A and Brelles-Mariño, G},
title = {The Pseudomonas aeruginosa biofilm matrix and cells are drastically impacted by gas discharge plasma treatment: A comprehensive model explaining plasma-mediated biofilm eradication.},
journal = {PloS one},
volume = {14},
number = {6},
pages = {e0216817},
doi = {10.1371/journal.pone.0216817},
pmid = {31233528},
issn = {1932-6203},
abstract = {Biofilms are microbial communities encased in a protective matrix composed of exopolymeric substances including exopolysaccharides, proteins, lipids, and extracellular DNA. Biofilms cause undesirable effects such as biofouling, equipment damage, prostheses colonization, and disease. Biofilms are also more resilient than free-living cells to regular decontamination methods and therefore, alternative methods are needed to eradicate them. The use of non-thermal atmospheric pressure plasmas is a good alternative as plasmas contain reactive species, free radicals, and UV photons well-known for their decontamination potential against free microorganisms. Pseudomonas aeruginosa biofilms colonize catheters, indwelling devices, and prostheses. Plasma effects on cell viability have been previously documented for P. aeruginosa biofilms. Nonetheless, the effect of plasma on the biofilm matrix has received less attention and there is little evidence regarding the changes the matrix undergoes. The aim of this work was to study the effect plasma exerts mostly on the P. aeruginosa biofilm matrix and to expand the existing knowledge about its effect on sessile cells in order to achieve a better understanding of the mechanism/s underlying plasma-mediated biofilm inactivation. We report a reduction in the amount of the biofilm matrix, the loss of its tridimensional structure, and morphological changes in sessile cells at long exposure times. We show chemical and structural changes on the biofilm matrix (mostly on carbohydrates and eDNA) and cells (mostly on proteins and lipids) that are more profound with longer plasma exposure times. We also demonstrate the presence of lipid oxidation products confirming cell membrane lipid peroxidation as plasma exposure time increases. To our knowledge this is the first report providing detailed evidence of the variety of chemical and structural changes that occur mostly on the biofilm matrix and sessile cells as a consequence of the plasma treatment. Based on our results, we propose a comprehensive model explaining plasma-mediated biofilm inactivation.},
}
@article {pmid31233504,
year = {2019},
author = {MacKenzie, KD and Wang, Y and Musicha, P and Hansen, EG and Palmer, MB and Herman, DJ and Feasey, NA and White, AP},
title = {Parallel evolution leading to impaired biofilm formation in invasive Salmonella strains.},
journal = {PLoS genetics},
volume = {15},
number = {6},
pages = {e1008233},
doi = {10.1371/journal.pgen.1008233},
pmid = {31233504},
issn = {1553-7404},
abstract = {Pathogenic Salmonella strains that cause gastroenteritis are able to colonize and replicate within the intestines of multiple host species. In general, these strains have retained an ability to form the rdar morphotype, a resistant biofilm physiology hypothesized to be important for Salmonella transmission. In contrast, Salmonella strains that are host-adapted or even host-restricted like Salmonella enterica serovar Typhi, tend to cause systemic infections and have lost the ability to form the rdar morphotype. Here, we investigated the rdar morphotype and CsgD-regulated biofilm formation in two non-typhoidal Salmonella (NTS) strains that caused invasive disease in Malawian children, S. Typhimurium D23580 and S. Enteritidis D7795, and compared them to a panel of NTS strains associated with gastroenteritis, as well as S. Typhi strains. Sequence comparisons combined with luciferase reporter technology identified key SNPs in the promoter region of csgD that either shut off biofilm formation completely (D7795) or reduced transcription of this key biofilm regulator (D23580). Phylogenetic analysis showed that these SNPs are conserved throughout the African clades of invasive isolates, dating as far back as 80 years ago. S. Typhi isolates were negative for the rdar morphotype due to truncation of eight amino acids from the C-terminus of CsgD. We present new evidence in support of parallel evolution between lineages of nontyphoidal Salmonella associated with invasive disease in Africa and the archetypal host-restricted invasive serovar; S. Typhi. We hypothesize that the African invasive isolates are becoming human-adapted and 'niche specialized' with less reliance on environmental survival, as compared to gastroenteritis-causing isolates.},
}
@article {pmid31232165,
year = {2019},
author = {Wang, Y and Wang, Y and Liu, B and Wang, S and Li, J and Gong, S and Sun, L and Yi, L},
title = {pdh modulate virulence through reducing stress tolerance and biofilm formation of Streptococcus suis serotype 2.},
journal = {Virulence},
volume = {10},
number = {1},
pages = {588-599},
doi = {10.1080/21505594.2019.1631661},
pmid = {31232165},
issn = {2150-5608},
abstract = {Streptococcus suis serotype 2 (S. suis 2) is a zoonotic pathogen. It causes meningitis, arthritis, pneumonia and sepsis in pigs, leading to extremely high mortality, which seriously affects public health and the development of the pig industry. Pyruvate dehydrogenase (PDH) is an important sugar metabolism enzyme that is widely present in microorganisms, mammals and higher plants. It catalyzes the irreversible oxidative decarboxylation of pyruvate to acetyl-CoA and reduces NAD+ to NADH. In this study, we found that the virulence of the S. suis ZY05719 sequence type 7 pdh deletion strain (Δpdh) was significantly lower than the wild-type strain (WT) in the mouse infection model. The distribution of viable bacteria in the blood and organs of mice infected with the Δpdh was significantly lower than those infected with WT. Bacterial survival rates were reduced in response to temperature stress, salt stress and oxidative stress. Additionally, compared to WT, the ability to adhere to and invade PK15 cells, biofilm formation and stress resistance of Δpdh were significantly reduced. Moreover, real-time PCR results showed that pdh deletion reduced the expression of multiple adhesion-related genes. However, there was no significant difference in the correlation biological analysis between the complemented strain (CΔpdh) and WT. Moreover, the survival rate of Δpdh in RAW264.7 macrophages was significantly lower than that of the WT strain. This study shows that PDH is involved in the pathogenesis of S. suis 2 and reduction in virulence of Δpdh may be related to the decreased ability to resist stress of the strain.},
}
@article {pmid31232051,
year = {2019},
author = {Perkowski, K and Baltaza, W and Conn, DB and Marczyńska-Stolarek, M and Chomicz, L},
title = {Examination of oral biofilm microbiota in patients using fixed orthodontic appliances in order to prevent risk factors for health complications.},
journal = {Annals of agricultural and environmental medicine : AAEM},
volume = {26},
number = {2},
pages = {231-235},
doi = {10.26444/aaem/105797},
pmid = {31232051},
issn = {1898-2263},
mesh = {Adolescent ; Bacteria/classification/genetics/isolation &amp; purification ; Bacterial Physiological Phenomena ; *Biofilms ; Child ; Female ; Humans ; Male ; Microbiota ; Mouth/*microbiology ; Oral Hygiene ; Orthodontic Appliances, Fixed/*microbiology ; Poland ; Young Adult ; },
abstract = {INTRODUCTION AND OBJECTIVE: In recent decades the use of orthodontic appliances in Poland has increased; however, data on their influence on changes of components of the microbiome connected with oral biofilm are scarce. The objective of this study was to evaluate oral microbiota in terms of their role as risk factors for health complications.<br><br>MATERIAL AND METHODS: The study included 100 patients treated with removable or fixed appliances. Oral hygiene and gingival health were determined, and periodontal swabs taken from each patient for parasitological, bacteriological and mycological microscopic and in vitro examinations.<br><br>RESULTS: Oral protists and various pathogenic and opportunistic bacterial and fungal strains were identified in the superficial layer of biofilm. A higher prevalence of bacteria, Enterococcus faecalis, E. faecium, Staphylococcus aureus and Escherichia coli, and various strains of yeast-like fungi from the Candida albicans group, occurred in patients treated with the fixed appliance than in those using a removable appliance or not treated orthodontically. In some periodontal samples from patients treated with fixed appliances, cysts of the Acanthamoeba spp. were found.<br><br>CONCLUSIONS: The use of orthodontic appliances alters the status of the oral cavity; it has impact on the colonization of oral biofilm by opportunistic/pathogenic strains, and increases the risk of their dissemination to various human tissues and organs. Pretreatment examination of oral microbiome, its monitoring particularly during treatment with fixed appliances, and preventive elimination of the potentially pathogenic strains to avoid health complications, are highly recommended, especially in patients with impaired immunity.},
}
@article {pmid31231348,
year = {2019},
author = {Singh, VK and Mishra, A and Jha, B},
title = {3-Benzyl-Hexahydro-Pyrrolo[1,2-a]Pyrazine-1,4-Dione Extracted From Exiguobacterium indicum Showed Anti-biofilm Activity Against Pseudomonas aeruginosa by Attenuating Quorum Sensing.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1269},
doi = {10.3389/fmicb.2019.01269},
pmid = {31231348},
issn = {1664-302X},
abstract = {Bacterial cell-to-cell communication promotes biofilm formation and can potentially lead to multidrug resistance development. Quorum sensing inhibition (QSI) is an effective and widely employed strategy against biofilm formation. The extract from Exiguobacterium indicum SJ16, a gram-positive bacterium, isolated from the rhizosphere of Cyperus laevigatus showed significant anti-quorum sensing activity (about 99%) against the reference Chromobacterium violaceum CV026 strain without exerting any antibacterial effect. The potentially active QSI compound identified in the SJ16 extract was 3-Benzyl-hexahydro-pyrrolo[1, 2-a]pyrazine-1,4-dione. The SJ16 extract containing this active compound showed significant anti-quorum sensing activity against a model quorum sensing bacterium strain Pseudomonas aeruginosa PAO1 and a clinical isolate P. aeruginosa PAH by preventing biofilm formation without attenuating the cell growth within the biofilm. More specifically, the SJ16 extract changed the topography and architecture of the biofilm, thus preventing bacterial adherence and further development of the biofilm. Furthermore, it decreased virulence factors (rhamnolipid and pyocyanin), the bacterial motility, as well as the elastase, and protease activities in P. aeruginosa. Microarray analysis revealed the differential expression of quorum sensing regulatory genes. Based on these results, we herein propose a hypothetical model, characterizing the role of this QSI agent in the transcriptional regulation of quorum sensing in P. aeruginosa PAO1, demonstrating that this compound has significant drug-development potential. Further research is required to delineate its possible applications in therapeutics in the context of biofilm forming bacterial infections.},
}
@article {pmid31231324,
year = {2019},
author = {Pathirana, RU and McCall, AD and Norris, HL and Edgerton, M},
title = {Filamentous Non-albicans Candida Species Adhere to Candida albicans and Benefit From Dual Biofilm Growth.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1188},
doi = {10.3389/fmicb.2019.01188},
pmid = {31231324},
issn = {1664-302X},
abstract = {Non-albicans Candida species (NACS) are often isolated along with Candida albicans in cases of oropharyngeal candidiasis. C. albicans readily forms biofilms in conjunction with other oral microbiota including both bacteria and yeast. Adhesion between species is important to the establishment of these mixed biofilms, but interactions between C. albicans and many NACS are not well-characterized. We adapted a real-time flow biofilm model to study adhesion interactions and biofilm establishment in C. albicans and NACS in mono- and co-culture. Out of five NACS studied, only the filamenting species C. tropicalis and C. dubliniensis were capable of adhesion with C. albicans, while C. parapsilosis, C. lusitaniae, and C. krusei were not. Over the early phase (0-4 h) of biofilm development, both mono- and co-culture followed similar kinetics of attachment and detachment events, indicating that initial biofilm formation is not influenced by inter-species interactions. However, the NACS showed a preference for inter-species cell-cell interactions with C. albicans, and at later time points (5-11 h) we found that dual-species interactions impacted biofilm surface coverage. Dual-species biofilms of C. tropicalis and C. albicans grew more slowly than C. albicans alone, but achieved higher surface coverage than C. tropicalis alone. Biofilms of C. dubliniensis with C. albicans increased surface coverage more rapidly than either species alone. We conclude that dual culture biofilm of C. albicans with C. tropicalis or C. dubliniensis offers a growth advantage for both NACS. Furthermore, the growth and maintenance, but not initial establishment, of dual-species biofilms is likely facilitated by interspecies cell-cell adherence.},
}
@article {pmid31230907,
year = {2019},
author = {Wang, J and Liu, Q and Ma, S and Hu, H and Wu, B and Zhang, XX and Ren, H},
title = {Distribution characteristics of N-acyl homoserine lactones during the moving bed biofilm reactor biofilm development process: Effect of carbon/nitrogen ratio and exogenous quorum sensing signals.},
journal = {Bioresource technology},
volume = {289},
number = {},
pages = {121591},
doi = {10.1016/j.biortech.2019.121591},
pmid = {31230907},
issn = {1873-2976},
abstract = {Carbon/nitrogen (C/N) ratios play an important role in biological wastewater treatment processes, with quorum sensing (QS) coordinating biological group behaviors. However, the relationship between them remains unclear. This study investigated the effects of varying C/N ratios and exogenous QS signals on the distribution characteristics of AHLs in Moving Bed Biofilm Reactors during the biofilm development process. Results show that C10-HSL and C12-HSL were the dominant AHLs, with the highest concentrations observed in the reactor with a C/N ratio of 10, followed by C/N ratios of 20 and 4. With varying C/N ratios, the biofilm microbial community structure changed significantly, which may contribute to significant differences in the distribution of AHLs. Furthermore, with the addition of a QS strain Sphingomonas rubra sp. nov., the pollutant removal efficiency of the reactor was not significantly improved and a reversible change in community composition was temporarily observed.},
}
@article {pmid31229548,
year = {2019},
author = {Bellich, B and Distefano, M and Syrgiannis, Z and Bosi, S and Guida, F and Rizzo, R and Brady, JW and Cescutti, P},
title = {The polysaccharide extracted from the biofilm of Burkholderia multivorans strain C1576 binds hydrophobic species and exhibits a compact 3D-structure.},
journal = {International journal of biological macromolecules},
volume = {136},
number = {},
pages = {944-950},
doi = {10.1016/j.ijbiomac.2019.06.140},
pmid = {31229548},
issn = {1879-0003},
support = {R01 GM123283/GM/NIGMS NIH HHS/United States ; },
abstract = {Microorganisms often grow in communities called biofilms where cells are imbedded in a complex self-produced biopolymeric matrix composed mainly of polysaccharides, proteins, and DNA. This matrix, together with cell proximity, confers many advantages to these microbial communities, but also constitutes a serious concern when biofilms develop in human tissues or on implanted prostheses. Although polysaccharides are considered the main constituents of the matrices, their specific role needs to be clarified. We have investigated the chemical and morphological properties of the polysaccharide extracted from biofilms produced by the C1576 reference strain of the opportunistic pathogen Burkholderia multivorans, which causes lung infections in cystic fibrosis patients. The aim of the present study is the definition of possible interactions of the polysaccharide and the three-dimensional conformation of its chain within the biofilm matrix. Surface plasmon resonance experiments confirmed the ability of the polysaccharide to bind hydrophobic molecules, due to the presence of rhamnose dimers in its primary structure. In addition, atomic force microscopy studies evidenced an extremely compact three-dimensional structure of the polysaccharide which may form aggregates, suggesting a novel view of its structural role into the biofilm matrix.},
}
@article {pmid31229099,
year = {2019},
author = {Cruzado-Bravo, MLM and Silva, NCC and Rodrigues, MX and Silva, GOE and Porto, E and Sturion, GL},
title = {Phenotypic and genotypic characterization of Staphylococcus spp. isolated from mastitis milk and cheese processing: Study of adherence and biofilm formation.},
journal = {Food research international (Ottawa, Ont.)},
volume = {122},
number = {},
pages = {450-460},
doi = {10.1016/j.foodres.2019.04.017},
pmid = {31229099},
issn = {1873-7145},
abstract = {The aim of this study was to identify the phenotypic and genotypic profiles of Staphylococcus spp. isolated from mastitis milk and cheese processing plant.To evaluate the biofilm production of wild-type strains on contact surfaces by testing different factors through adhered cells and biofilm quantifications, finally, these biofilms were observed by Scanning Electron Microscopy (SEM). Congo red agar (CRA) plate method was used to identify slime production by strains. Screening of genes encoding adhesion factors and biofilm formation was carried out using PCR. After strains selection, adhesion and biofilm assays were designed testing different times (12, 48, 96 h), strains (n = 13), contact surfaces (stainless steel and polypropylene), and temperatures (5 °C and 25 °C); and then, bacterial count and crystal violet staining were conducted. Relative frequencies of positive on CRA and genes presence were determined, and Friedman test was applied for bacterial counts and OD values. Additionally, significant factors (P ≤ .05) were subjected to multiple comparisons using the Nemenyi test. The slime production in CRA was observed by visual inspection in 38.7% of strains. A large distribution of genes was described among strains, implying a high variability of genotypic profiles. Moreover, relative frequencies of CRA positive and gene presence were described. The developed assay showed that the strain, temperature, contact surface, were significant for both variables. The SEM corroborated the findings, showing greater biofilm formation on stainless steel at 25 °C. Thus, it is essential to highlight the importance of temperature control and material with low superficial energy to avoid biofilm formation by staphylococci.},
}
@article {pmid31228833,
year = {2019},
author = {Wang, J and Liu, Q and Hu, H and Wu, B and Zhang, XX and Ren, H},
title = {Insight into mature biofilm quorum sensing in full-scale wastewater treatment plants.},
journal = {Chemosphere},
volume = {234},
number = {},
pages = {310-317},
doi = {10.1016/j.chemosphere.2019.06.007},
pmid = {31228833},
issn = {1879-1298},
abstract = {Quorum sensing (QS) has been thoroughly investigated during initial biofilm formation stages, while the role of QS in mature biofilms has received little research attention. This study assessed QS in 22 biofilm samples from full-scale wastewater treatment plants in China. Results showed that the concentration of acyl-homoserine lactones (AHLs) in various biofilm bound forms, ranged from 15.63 to 609.76 ng/g. The highest concentration of AHLs was found in the tightly bound biofilm fraction, while the lowest concentrations were observed in the surface biofilm fraction. Environmental variables, C/N ratio and temperature, were found to be significant factors influencing biofilm AHL distribution (p < 0.01). Higher C/N ratios (ranging from 3 to 12) and low temperatures contributed to the higher concentration of AHLs in biofilms. Dominant AHLs (C10-HSL and C12-HSL) were significantly associated with biofilm activity (R2 = 0.98/0.97, p < 0.05), with the tightly bound biofilm fraction (TB-biofilm) presenting the highest activity (ATP concentration). Biofilm aging and re-formation processes were more active in the surface biofilm layer (S-biofilm), while the stable structure of the TB-biofilm layer which is attached to the surface of bio-carriers ensures high biofilm activity. This study furthers our understanding of the roles of AHLs in the regulation of mature biofilm activities.},
}
@article {pmid31228790,
year = {2019},
author = {Luo, JH and Wu, M and Liu, J and Qian, G and Yuan, Z and Guo, J},
title = {Microbial chromate reduction coupled with anaerobic oxidation of methane in a membrane biofilm reactor.},
journal = {Environment international},
volume = {130},
number = {},
pages = {104926},
doi = {10.1016/j.envint.2019.104926},
pmid = {31228790},
issn = {1873-6750},
abstract = {It has been reported that microbial reduction of sulfate, nitrite/nitrate and iron/manganese could be coupled with anaerobic oxidation of methane (AOM), which plays a significant role in controlling methane emission from anoxic niches. However, little is known about microbial chromate (Cr(VI)) reduction coupling with AOM. In this study, a microbial consortium was enriched via switching nitrate dosing to chromate feeding as the sole electron acceptor under anaerobic condition in a membrane biofilm reactor (MBfR), in which methane was continuously provided as the electron donor through bubble-less hollow fiber membranes. According to long-term reactor operation and chromium speciation analysis, soluble chromate could be reduced into Cr(III) compounds by using methane as electron donor. Fluorescence in situ hybridization and high-throughput 16S rRNA gene amplicon profiling further indicated that after feeding chromate Candidatus 'Methanoperedens' (a known nitrate-dependent anaerobic methane oxidation archaeon) became sole anaerobic methanotroph in the biofilm, potentially responsible for the chromate bio-reduction driven by methane. Two potential pathways of the microbial AOM-coupled chromate reduction were proposed: (i) Candidatus 'Methanoperedens' independently utilizes chromate as electron acceptor to form Cr(III) compounds, or (ii) Candidatus 'Methanoperedens' oxidizes methane to generate intermediates or electrons, which will be utilized to reduce chromate to Cr(III) compounds by unknown chromate reducers synergistically. Our findings suggest a possible link between the biogeochemical chromium and methane cycles.},
}
@article {pmid31228542,
year = {2019},
author = {Cardoso, MH and Santos, VPM and Costa, BO and Buccini, DF and Rezende, SB and Porto, WF and Santos, MJ and Silva, ON and Ribeiro, SM and Franco, OL},
title = {A short peptide with selective anti-biofilm activity against Pseudomonas aeruginosa and Klebsiella pneumoniae carbapenemase-producing bacteria.},
journal = {Microbial pathogenesis},
volume = {135},
number = {},
pages = {103605},
doi = {10.1016/j.micpath.2019.103605},
pmid = {31228542},
issn = {1096-1208},
abstract = {Biofilm-related infections represent an enormous clinical challenge nowadays. In this context, diverse studies are underway to develop effective antimicrobial agents targeting bacterial biofilms. Here, we describe the antibacterial and anti-biofilm activities of a short, cationic peptide named R5F5, obtained from sliding-window analysis based on a peptide (PcDBS1R5) derived from Plasmodium chabaudi. Ten fragments were generated (R5F1 to F10) and submitted to initial antibacterial assays against Pseudomonas aeruginosa. As a result, R5F5 showed the highest antimicrobial activity. We therefore carried out further antibacterial and anti-biofilm assays against P. aeruginosa and Klebsiella pneumoniae carbapenemase-producing bacterial strains. R5F5 revealed selective anti-biofilm activity, as the peptide inhibited >60% biofilm formation in all cases from 8 to 64 μg·mL-1. Moreover, R5F5 was not hemolytic against mice erythrocytes at 640 μg mL-1. Cytotoxic effects on human lung fibroblast cells were not detected at 160 μg·mL-1. Structural studies revealed that R5F5 presents random coil conformations in water and 50% 2,2,2-trifluoroethanol (TFE)/water (v/v), whereas amphipathic, extended conformations were observed in contact with sodium dodecyl sulfate (SDS) micelles. Thus, here we report a novel peptide with selective anti-biofilm activity against susceptible and resistant bacterial strains, with no toxicity toward mammalian cells and that adopts a stable structure in anionic environment.},
}
@article {pmid31226983,
year = {2019},
author = {Sánchez, MC and Ribeiro-Vidal, H and Esteban-Fernández, A and Bartolomé, B and Figuero, E and Moreno-Arribas, MV and Sanz, M and Herrera, D},
title = {Antimicrobial activity of red wine and oenological extracts against periodontal pathogens in a validated oral biofilm model.},
journal = {BMC complementary and alternative medicine},
volume = {19},
number = {1},
pages = {145},
doi = {10.1186/s12906-019-2533-5},
pmid = {31226983},
issn = {1472-6882},
support = {ALIBIRD-CM S2013/ABI-2728//Comunidad de Madrid/ ; AGL2015-64522-C2-R project//Spanish MINECO/ ; },
mesh = {Aggregatibacter actinomycetemcomitans/drug effects/physiology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Fusobacterium nucleatum/*drug effects/physiology ; Humans ; Periodontal Diseases/*microbiology ; Plant Extracts/*pharmacology ; Polyphenols/pharmacology ; Porphyromonas gingivalis/drug effects/physiology ; Seeds/chemistry ; Vitis/chemistry ; Wine/*analysis ; },
abstract = {BACKGROUND: Previous research findings support an antimicrobial effect of polyphenols against a variety of pathogens, but there is no evidence of this effect against periodontal pathogens in complex biofilms. The purpose of this study was to evaluate the antimicrobial activity of red wine and oenological extracts, rich in polyphenols, against the periodontal pathogens Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum and total bacteria growing in an in vitro oral biofilm static model.<br><br>METHODS: A previously validated biofilm model, including Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, F. nucleatum, P. gingivalis and A. actinomycetemcomitans was developed on sterile hydroxyapatite discs. Red wine (and dealcoholized wine), and two polyphenols-rich extracts (from wine and grape seeds) were applied to 72 h biofilms by dipping the discs during 1 and 5 min in the wine solutions and during 30 s and 1 min in the oenological extracts. Resulting biofilms were analyzed by confocal laser scanning microscopy and viable bacteria (colony forming units/mL) were measured by quantitative polymerase chain reaction combined with propidium monoazide. A generalized linear model was constructed to determine the effect of the tested products on the viable bacterial counts of A. actinomycetemcomitans, P. gingivalis and F. nucleatum, as well on the total number of viable bacteria.<br><br>RESULTS: The results showed that red wine and dealcoholized red wine caused reduction in viability of total bacteria within the biofilm, with statistically significant reductions in the number of viable P. gingivalis after 1 min (p = 0.008) and in A. actinomycetemcomitans after 5 min of exposure (p = 0.011) with red wine. No evidence of relevant antibacterial effect was observed with the oenological extracts, with statistically significant reductions of F. nucleatum after 30 s of exposure to both oenological extracts (p = 0.001).<br><br>CONCLUSIONS: Although moderate, the antimicrobial impact observed in the total bacterial counts and counts of A. actinomycetemcomitans, P. gingivalis and F. nucleatum, encourage further investigations on the potential use of these natural products in the prevention and treatment of periodontal diseases.},
}
@article {pmid31226270,
year = {2019},
author = {Short, B and Brown, J and Delaney, C and Sherry, L and Williams, C and Ramage, G and Kean, R},
title = {Candida auris exhibits resilient biofilm characteristics in vitro: implications for environmental persistence.},
journal = {The Journal of hospital infection},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jhin.2019.06.006},
pmid = {31226270},
issn = {1532-2939},
abstract = {Surfaces within healthcare play a key role in the transmission of drug-resistant pathogens. Candida auris is an emerging multidrug-resistant yeast which can survive for prolonged periods on environmental surfaces. Here we show that the ability to form cellular aggregates increases survival after 14 days, which coincides with the upregulation of biofilm-associated genes. Additionally, the aggregating strain demonstrated tolerance to clinical concentrations of sodium hypochlorite and remained viable 14 days post treatment. The ability of C. auris to adhere to and persist on environmental surfaces emphasizes our need to better understand the biology of this fungal pathogen.},
}
@article {pmid31222089,
year = {2019},
author = {Ramos-Vivas, J and Chapartegui-González, I and Fernández-Martínez, M and González-Rico, C and Fortún, J and Escudero, R and Marco, F and Linares, L and Montejo, M and Aranzamendi, M and Muñoz, P and Valerio, M and Aguado, JM and Resino, E and Ahufinger, IG and Vega, AP and Martínez, L and Fariñas, MC and , },
title = {Biofilm formation by multidrug resistant Enterobacteriaceae strains isolated from solid organ transplant recipients.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {8928},
doi = {10.1038/s41598-019-45060-y},
pmid = {31222089},
issn = {2045-2322},
abstract = {Solid organ transplant (SOT) recipients are especially at risk of developing infections by multidrug resistant bacteria (MDR). In this study, the biofilm-forming capability of 209 MDR strains (Escherichia coli n = 106, Klebsiella pneumoniae n = 78, and Enterobacter spp. n = 25) isolated from rectal swabs in the first 48 hours before or after kidney (93 patients), liver (60 patients) or kidney/pancreas transplants (5 patients) were evaluated by using a microplate assay. Thirty-nine strains were isolated before transplant and 170 strains were isolated post-transplant. Overall, 16% of E. coli strains, 73% of K. pneumoniae strains and 4% Enterobacter strains showed moderate or strong biofilm production. Nine strains isolated from infection sites after transplantation were responsible of infections in the first month. Of these, 4 K. pneumoniae, 1 E. coli and 1 Enterobacter spp. strains isolated pre-transplant or post-transplant as colonizers caused infections in the post-transplant period. Our results suggest that in vitro biofilm formation could be an important factor for adhesion to intestine and colonization in MDR K. pneumoniae strains in SOT recipients, but this factor appears to be less important for MDR E. coli and Enterobacter spp.},
}
@article {pmid31222015,
year = {2019},
author = {Tassinari, E and Duffy, G and Bawn, M and Burgess, CM and McCabe, EM and Lawlor, PG and Gardiner, G and Kingsley, RA},
title = {Microevolution of antimicrobial resistance and biofilm formation of Salmonella Typhimurium during persistence on pig farms.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {8832},
doi = {10.1038/s41598-019-45216-w},
pmid = {31222015},
issn = {2045-2322},
support = {BB/R012504/1//RCUK | Biotechnology and Biological Sciences Research Council (BBSRC)/ ; BB/N007964/1//RCUK | Biotechnology and Biological Sciences Research Council (BBSRC)/ ; BB/M025489/1//RCUK | Biotechnology and Biological Sciences Research Council (BBSRC)/ ; 2015028//Teagasc/ ; },
abstract = {Salmonella Typhimurium and its monophasic variant S. 4,[5],12:i:- are the dominant serotypes associated with pigs in many countries. We investigated their population structure on nine farms using whole genome sequencing, and their genotypic and phenotypic variation. The population structure revealed the presence of phylogenetically distinct clades consisting of closely related clones of S. Typhimurium or S. 4,[5],12:i:- on each pig farm, that persisted between production cycles. All the S. 4,[5],12:i:- strains carried the Salmonella genomic island-4 (SGI-4), which confers resistance to heavy metals, and half of the strains contained the mTmV prophage, harbouring the sopE virulence gene. Most clonal groups were highly drug resistant due to the presence of multiple antimicrobial resistance (AMR) genes, and two clades exhibited evidence of recent on-farm plasmid-mediated acquisition of additional AMR genes, including an IncHI2 plasmid. Biofilm formation was highly variable but had a strong phylogenetic signature. Strains capable of forming biofilm with the greatest biomass were from the S. 4,[5],12:i:- and S. Typhimurium DT104 clades, the two dominant pandemic clones found over the last 25 years. On-farm microevolution resulted in enhanced biofilm formation in subsequent production cycle.},
}
@article {pmid31220767,
year = {2019},
author = {Zhong, H and Wang, H and Tian, Y and Liu, X and Yang, Y and Zhu, L and Yan, S and Liu, G},
title = {Treatment of polluted surface water with nylon silk carrier-aerated biofilm reactor (CABR).},
journal = {Bioresource technology},
volume = {289},
number = {},
pages = {121617},
doi = {10.1016/j.biortech.2019.121617},
pmid = {31220767},
issn = {1873-2976},
abstract = {Carrier aerated biofilm reactor (CABR) with nylon silk as the biofilm growth carrier was constructed to treatment of polluted surface water, which could improve the practical application in comparison with MABR process. The results show that CABR process can effectively improve the self-purification capacity of the polluted surface water, efficient removal of COD and NH3-N, making water quality achieve the level V of Environmental Quality Standards for Surface Water (GB 3838-2002, China). Modified nylon silk can alter the community structures and increase bacteria during CABR process operation. Large pore size of nylon silk leads to the formation of special biofilm structure in CABR. Extracellular polymer (EPS) and membrane fouling resistance distribution indicated that the nylon silk fouling control ability of CABR reactor is much higher than that of membrane-aerated biofilm reactors (MABR). The results show that the CABR process can effectively purify surface water and improve the practical application.},
}
@article {pmid31220446,
year = {2019},
author = {Lee, TH and Jung, MK and Kim, TK and Pack, CG and Park, YK and Kim, SO and Park, DH},
title = {Safety and efficacy of a metal stent covered with a silicone membrane containing integrated silver particles in preventing biofilm and sludge formation in endoscopic drainage of malignant biliary obstruction: a phase 2 pilot study.},
journal = {Gastrointestinal endoscopy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.gie.2019.06.007},
pmid = {31220446},
issn = {1097-6779},
abstract = {BACKGROUND AND AIMS: Membrane-covered self-expandable metal stents (SEMSs) have been developed to prolong the patency of stents by reducing tissue hyperplasia or tumor ingrowth. However, their effectiveness is attenuated by stent clogging as a result of biofilm formation on the inner surface of the membrane. The aim of this pilot study was to evaluate the efficacy and safety of SEMSs covered with a silicone membrane containing integrated silver particles (Ag-P) in malignant distal biliary obstruction.<br><br>METHODS: Twenty-four patients who underwent SEMS placement because of malignant distal biliary obstruction were enrolled in this single-center pilot study. The main outcomes were technical success, clinical success, adverse events, stent patency, and survival.<br><br>RESULTS: The technical and clinical success rates were 100% and 91.7% (22 of 24), respectively. The rates of early and late adverse events were 22.7% and 36.4%, respectively. The primary reintervention rate was 27.3% (6 of 22). Only 1 case involving stent malfunction was associated with sludge impaction. Median stent patency was 179 days. During follow-up, there were no serious adverse events or mortality related to the stents or Ag-P. Serum and urine silver concentrations before and after stent placement and at 32 weeks after placement did not differ. All serum and urine silver concentrations were <3 μg/L (3 ppb) and 5 μg/L (5 ppb), respectively.<br><br>CONCLUSIONS: SEMSs covered with a silicone membrane containing integrated Ag-Ps may be effective and safe in malignant distal biliary obstruction. Stent dysfunction related to sludge impaction may be less frequent using this new stent. (Clinical Research Information Service identifier: KCT 0002310.).},
}
@article {pmid31219091,
year = {2019},
author = {George, J and Halami, PM},
title = {Presence of extracellular DNA &amp; protein in biofilm formation by gentamicin-resistant Lactobacillus plantarum.},
journal = {The Indian journal of medical research},
volume = {149},
number = {2},
pages = {257-262},
doi = {10.4103/ijmr.IJMR_2022_17},
pmid = {31219091},
issn = {0971-5916},
abstract = {Background &amp; objectives: Bacterial biofilms a multi-layered defence, comprise extracellular DNA (eDNA) and proteins, protect bacteria from harmful environment and nutrient limitation and utilize the mutual benefits within a community. Bacterial biofilms also defend bacteria from harsh environments such as antibiotic treatment. This leads to poor antibiotic penetration, slow growth, adaptive stress responses, and formation of persister cells. This study was done to determine the relation of antibiotic resistance deciphered by the biofilms in Lactobacillus plantarum, a lactic acid bacteria (LAB) with probiotic significance.<br><br>Methods: The gentamicin-resistant L. plantarum isolates were allowed to form biofilms and subjected to DNase I and proteinase K treatment. The optical density (OD) values were recorded for the biofilm assay and the cell count for the number of viable cells was taken for the control and the test samples. Percentage reduction was calculated based on the difference between the initial and final OD for both the parameters.<br><br>Results: The biofilm assay revealed that the native L. plantarum isolates which were phenotypically susceptible, possessed the ability to form biofilms. The OD values were significantly decreased in comparison to the biofilm-forming control culture when these were treated with DNase I and proteinase K.<br><br>The study revealed that the biofilms formed by L. plantarum comprised of eDNA and proteins which was evidenced by the reduction in OD values and percentage in comparison to the control upon DNase I and proteinase K treatment. This indicates that the eDNA and biofilm matrix proteins are vital constituents of biofilms and may carry significant risk when coupled with antibiotic resistance.},
}
@article {pmid31218543,
year = {2019},
author = {Pepoyan, AZ and Manvelyan, AM and Balayan, MH and Galstyan, S and Tsaturyan, VV and Grigoryan, B and Chikindas, ML},
title = {Low-Dose Electron-Beam Irradiation for the Improvement of Biofilm Formation by Probiotic Lactobacilli.},
journal = {Probiotics and antimicrobial proteins},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12602-019-09566-1},
pmid = {31218543},
issn = {1867-1314},
support = {A-2134//The International Science and Technology Center/ ; 17A-1F010//CANDLE Synchrotron Research Institute foundation/ ; },
abstract = {The effects of 50-150 gray electron-beam irradiation on the biofilm-formation ability and cell surface hydrophobicity of the commercial strain, Lactobacillus acidophilus DDS®-1, from Lacto-G (a marketed synbiotic formulation) and the putative probiotic, L. rhamnosus Vahe, were evaluated. No significant changes in cell surface hydrophobicity were found after irradiation, while increases in biofilm-formation abilities were documented for both investigated microorganisms 0.22 ± 0.03 vs. 0.149 ± 0.02 (L. rhamnosus Vahe, 150 Gy) and 0.218 ± 0.021 vs. 0.17 ± 0.012 (L. acidophilus DDS®-1, 150 Gy). Given this, the use of electron-beam irradiation (50-100 Gy) for the treatment of L. rhamnosus Vahe and L. acidophilus DDS®-1 cells may be considered in product sterilization, quality improvement, and packaging practices.},
}
@article {pmid31218489,
year = {2019},
author = {De-la-Pinta, I and Cobos, M and Ibarretxe, J and Montoya, E and Eraso, E and Guraya, T and Quindós, G},
title = {Effect of biomaterials hydrophobicity and roughness on biofilm development.},
journal = {Journal of materials science. Materials in medicine},
volume = {30},
number = {7},
pages = {77},
doi = {10.1007/s10856-019-6281-3},
pmid = {31218489},
issn = {1573-4838},
abstract = {Most hospitalized patients are carriers of biomedical devices. Infections associated with these devices cause great morbidity and mortality, especially in patients in intensive care units. Numerous strategies have been designed to prevent biofilm development on biodevices. However, biofilm formation is a complex process not fully clarified. In the current study, roughness and hydrophobicity of different biomaterials was analyzed to assess their influences on the biofilm formation of four leading etiological causes of healthcare-associated infections, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis and Candida albicans, using a CDC biofilm reactor. Hydrophobic materials allowed the formation of more abundant and profuse biofilms. Roughness had effect on biofilm formation, but its influence was not significant when material hydrophobicity was considered.},
}
@article {pmid31218468,
year = {2019},
author = {Stacchi, C and Del Lupo, V and Berton, F and Lombardi, T and Bressan, R and Di Lenarda, R and Lagatolla, C},
title = {Aspergillus fumigatus biofilm formation on different bone substitutes used in maxillary sinus augmentation: an in vitro analysis.},
journal = {International journal of implant dentistry},
volume = {5},
number = {1},
pages = {22},
doi = {10.1186/s40729-019-0175-5},
pmid = {31218468},
issn = {2198-4034},
abstract = {BACKGROUND: Fungus ball (FB) typically affects healthy adults, and Aspergillus fumigatus is the most frequent etiologic agent: iatrogenic factors represent an important issue in FB pathogenesis. Moreover, a recent study suggested a significant association between the use of anorganic bovine bone as sinus grafting material and subsequent development of FB. The aim of the present investigation is to evaluate in vitro eventual differences in the ability of Aspergillus fumigatus to colonize different bone grafting materials and grow on them as biofilm.<br><br>FINDINGS: Five different bone substitutes (demineralized bone matrix, anorganic bovine bone, ß-tricalcium phosphate, synthetic nano-hydroxyapatite, and synthetic hydroxyapatite), commonly used in sinus floor augmentation procedures, were inoculated with conidia suspensions of A. fumigatus and incubated at 37 °C for 4 and 8 h, in standardized conditions. Biofilm bound to the different materials underwent quantitative and qualitative analysis by confocal and scanning electron microscopy. A. fumigatus proved to be able to adhere and form biofilm on all the tested bone substitutes. The surface plot representation of the samples displayed some differences in the density of the superficial layer, due to the physical characteristics of the biomaterials. Nevertheless, Kruskal-Wallis test showed no significant differences in biomass amount among the five bone substitutes (p = 0.236 and p = 0.55 after 4 and 8 h adhesion, respectively).<br><br>CONCLUSIONS: All the bone substitutes normally used in sinus floor augmentation represent a favorable substrate for fungal growth, due to their physical and chemical characteristics. During sinus floor elevation procedures, Schneiderian membrane integrity should be maintained in order to avoid the exposure of the grafting material at the respiratory environment, with potential risks of fungal colonization.},
}
@article {pmid31217919,
year = {2019},
author = {Khalifehzadeh, S and Haghanifar, S and Jenabian, N and Kazemi, S and Hajiahmadi, M},
title = {Clinical and radiographic evaluation of applying 1% metformin biofilm with plasma rich in growth factor (PRGF) for treatment of two-wall intrabony periodontal defects: A randomized clinical trial.},
journal = {Journal of dental research, dental clinics, dental prospects},
volume = {13},
number = {1},
pages = {51-56},
doi = {10.15171/joddd.2019.008},
pmid = {31217919},
issn = {2008-210X},
abstract = {Background . The ultimate aim of periodontal treatment is to regenerate periodontium and regenerative treatment after that. The aim of this study was to evaluate the effect of PRGF with 1% metformin biofilm in the treatment of two-wall intrabony periodontal defects. Methods . In this clinical trial, 8 patients with moderate chronic periodontitis and two-wall intrabony defect were selected. The defects were assigned to 4 groups: debridement, 1% metformin, PRGF, PRGF and metformin. The parameters of vertical probing depth, vertical clinical attachment level and gingival index were measured at baseline, immediately before surgery, and 3 and 6 months after surgery. In addition, the radiographic changes were evaluated with digital subtraction radiography before and 6 months after surgery. Analysis of the results was performed with repeated measurements, Friedman test and chisquared test. Results . All the groups exhibited improvements in all the clinical parameters after 6 months. Inter-group comparison of GI, CAL and PPD parameters revealed no statistically significant differences. Radiographic changes in the group of 1% metformin with PRGF revealed statistically significant differences compared with other groups; however, there were no statistically significant differences in other groups. Conclusion . Application of PRGF with 1% metformin in intrabony two-wall periodontal defects was effective in improving the clinical parameters but this effect revealed no difference compared with other groups; however, in terms of radiographic changes significant improvements were noted.},
}
@article {pmid31217374,
year = {2019},
author = {Zhou, G and Peng, H and Wang, YS and Huang, XM and Xie, XB and Shi, QS},
title = {Enhanced synergistic effects of xylitol and isothiazolones for inhibition of initial biofilm formation by Pseudomonas aeruginosa ATCC 9027 and Staphylococcus aureus ATCC 6538.},
journal = {Journal of oral science},
volume = {61},
number = {2},
pages = {255-263},
doi = {10.2334/josnusd.18-0102},
pmid = {31217374},
issn = {1880-4926},
abstract = {Bacterial biofilms, formed on biotic or abiotic surfaces, can lead to serious environmental or medical problems. Therefore, it is necessary to find novel antimicrobial agents to combat biofilms, or more effective combinations of existing biocides. In this study, initial biofilms of Pseudomonas aeruginosa ATCC 9027 and Staphylococcus aureus ATCC 6538 in the presence of xylitol or xylitol and isothiazolones were determined using crystal violet staining in 96-well microplates and confocal laser scanning microscopy. Xylitol and isothiazolones exhibited enhanced synergistic inhibition of initial biofilm formation, and also the structure and production of extracellular polymeric substances by P. aeruginosa ATCC 9027 and S. aureus ATCC 6538 in a dose-dependent manner. In addition, xylitol and isothiazolones inhibited and restored the swimming motility of P. aeruginosa ATCC 9027, respectively. These findings show that a combination of xylitol and isothiazolones exerts pronounced antimicrobial activity against P. aeruginosa and S. aureus biofilms and may be applicable for preventing or reducing bacterial biofilms in vitro.},
}
@article {pmid31217292,
year = {2019},
author = {Arnaouteli, S and Matoz-Fernandez, DA and Porter, M and Kalamara, M and Abbott, J and MacPhee, CE and Davidson, FA and Stanley-Wall, NR},
title = {Pulcherrimin formation controls growth arrest of the Bacillus subtilis biofilm.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {116},
number = {27},
pages = {13553-13562},
doi = {10.1073/pnas.1903982116},
pmid = {31217292},
issn = {1091-6490},
support = {//Wellcome Trust/United Kingdom ; },
abstract = {Biofilm formation by Bacillus subtilis is a communal process that culminates in the formation of architecturally complex multicellular communities. Here we reveal that the transition of the biofilm into a nonexpanding phase constitutes a distinct step in the process of biofilm development. Using genetic analysis we show that B. subtilis strains lacking the ability to synthesize pulcherriminic acid form biofilms that sustain the expansion phase, thereby linking pulcherriminic acid to growth arrest. However, production of pulcherriminic acid is not sufficient to block expansion of the biofilm. It needs to be secreted into the extracellular environment where it chelates Fe3+ from the growth medium in a nonenzymatic reaction. Utilizing mathematical modeling and a series of experimental methodologies we show that when the level of freely available iron in the environment drops below a critical threshold, expansion of the biofilm stops. Bioinformatics analysis allows us to identify the genes required for pulcherriminic acid synthesis in other Firmicutes but the patchwork presence both within and across closely related species suggests loss of these genes through multiple independent recombination events. The seemingly counterintuitive self-restriction of growth led us to explore if there were any benefits associated with pulcherriminic acid production. We identified that pulcherriminic acid producers can prevent invasion by neighboring communities through the generation of an &quot;iron-free&quot; zone, thereby addressing the paradox of pulcherriminic acid production by B. subtilis.},
}
@article {pmid31216375,
year = {2019},
author = {Palmioli, A and Sperandeo, P and Polissi, A and Airoldi, C},
title = {Targeting bacterial biofilm: a new LecA multivalent ligand with inhibitory activity.},
journal = {Chembiochem : a European journal of chemical biology},
volume = {},
number = {},
pages = {},
doi = {10.1002/cbic.201900383},
pmid = {31216375},
issn = {1439-7633},
abstract = {Biofilm formation by bacterial pathogens is a hallmark of chronic infections and is associated to increased antibiotic tolerance that makes pathogens difficult to eradicate with conventional antibiotic therapies. Infections caused by Pseudomonas aeruginosa are of great concern, especially for immunocompromised and cystic fibrosis patients. P. aeruginosa lectins LecA and LecB are virulence factors and play a key role in establishing biofilm; therefore, inhibition of the function of these proteins has potential in dismantling the bacterium from the protective biofilm environment and in restoring the activity of antibiotics. Here we report the NMR characterization of the binding of a galactose-based dendrimer (Gal18) to LecA. Moreover, we demonstrate the activity of Gal18 molecule in inhibiting P. aeruginosa biofilm formation in vitro.},
}
@article {pmid31216354,
year = {2019},
author = {Pickering, AC and Vitry, P and Prystopiuk, V and Garcia, B and Höök, M and Schoenebeck, J and Geoghegan, JA and Dufrêne, YF and Fitzgerald, JR},
title = {Host-specialized fibrinogen-binding by a bacterial surface protein promotes biofilm formation and innate immune evasion.},
journal = {PLoS pathogens},
volume = {15},
number = {6},
pages = {e1007816},
doi = {10.1371/journal.ppat.1007816},
pmid = {31216354},
issn = {1553-7374},
abstract = {Fibrinogen is an essential part of the blood coagulation cascade and a major component of the extracellular matrix in mammals. The interface between fibrinogen and bacterial pathogens is an important determinant of the outcome of infection. Here, we demonstrate that a canine host-restricted skin pathogen, Staphylococcus pseudintermedius, produces a cell wall-associated protein (SpsL) that has evolved the capacity for high strength binding to canine fibrinogen, with reduced binding to fibrinogen of other mammalian species including humans. Binding occurs via the surface-expressed N2N3 subdomains, of the SpsL A-domain, to multiple sites in the fibrinogen α-chain C-domain by a mechanism analogous to the classical dock, lock, and latch binding model. Host-specific binding is dependent on a tandem repeat region of the fibrinogen α-chain, a region highly divergent between mammals. Of note, we discovered that the tandem repeat region is also polymorphic in different canine breeds suggesting a potential influence on canine host susceptibility to S. pseudintermedius infection. Importantly, the strong host-specific fibrinogen-binding interaction of SpsL to canine fibrinogen is essential for bacterial aggregation and biofilm formation, and promotes resistance to neutrophil phagocytosis, suggesting a key role for the interaction during pathogenesis. Taken together, we have dissected a bacterial surface protein-ligand interaction resulting from the co-evolution of host and pathogen that promotes host-specific innate immune evasion and may contribute to its host-restricted ecology.},
}
@article {pmid31214138,
year = {2019},
author = {Flament-Simon, SC and Duprilot, M and Mayer, N and García, V and Alonso, MP and Blanco, J and Nicolas-Chanoine, MH},
title = {Association Between Kinetics of Early Biofilm Formation and Clonal Lineage in Escherichia coli.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1183},
doi = {10.3389/fmicb.2019.01183},
pmid = {31214138},
issn = {1664-302X},
abstract = {Background: Escherichia coli biofilm formation has mostly been assessed in specific pathogenic E. coli groups. Here, we assessed the early biofilm formation (EBF), i.e., adhesion stage, using the BioFilm Ring Test® on 394 E. coli clinical isolates (EC) [196 consecutively isolated (CEC) in 2016 and 198 ESBL-producing E. coli (ESBLEC) isolated in 2015]. Then, biofilm-forming ability was contrasted with phylogroups, clonotypes (fumC-fimH), and sequence types (STs), all being used to define clones, virulence factors (VF), and FimB.<br><br>Result: According to both biofilm production levels at 2, 3, and 5 h, and EBF kinetics over 5 h, CEC and ESBLEC isolates segregated into three EBF groups: strong (G1), moderate (G2), and weak (G3) producers. At 2 h, strong producers were more frequent among CEC (n = 28; 14.3%) than among ESBLEC (n = 8; 4%) (P = 0.0004). As CEC and ESBLEC isolates showed similar individual EBF kinetics in each group, a comparison of isolate features between each group was applied to gathered CEC and ESBLEC isolates after 2 h of incubation, 2 h being the most representative time point of the CEC and ESBLEC isolate segregation into the three groups. Phylogroup B2 displayed by 51.3% of the 394 isolates was more frequent in G1 (77.8%) than in G3 (47.6%) (P = 0.0006). The 394 isolates displayed 153 clones, of which 31 included at least three isolates. B2-CH14-2-ST127, B2-CH40-22-ST131, B2-CH52-5/14-ST141, and E-CH100-96-ST362 clones were associated with G1 (P < 0.03) and accounted for 41.7% of G1 isolates. B2-CH40-30-ST131 clone was associated with G3 (P < 0.0001) and accounted for 25.5% of G3 isolates. VF mean was higher among G1 than among G3 isolates (P < 0.001). FimB-P2 variant was associated with G1 (P = 0.0011) and FimB-P1 variant was associated with G3 (P = 0.0023). Clone, some VF, and FimB were associated with EBF, with clonal lineage being able to explain 72% of the variability of EBF.<br><br>Conclusion: Among our 394 isolates, <10% are able to quickly and persistently produce high biofilm levels over 5 h. These isolates belong to a few clones previously described in various studies as dominant gut colonizers in mammalians and birds and comprised the B2-CH40-22-ST131 clone, i.e., the ancestor of the globally disseminated B2-CH40-30-ST131 clone that is the dominant clone among the weak biofilm producers.},
}
@article {pmid31213555,
year = {2019},
author = {Keogh, D and Lam, LN and Doyle, LE and Matysik, A and Pavagadhi, S and Umashankar, S and Low, PM and Dale, JL and Song, Y and Ng, SP and Boothroyd, CB and Dunny, GM and Swarup, S and Williams, RBH and Marsili, E and Kline, KA},
title = {Correction for Keogh et al., &quot;Extracellular Electron Transfer Powers Enterococcus faecalis Biofilm Metabolism&quot;.},
journal = {mBio},
volume = {10},
number = {3},
pages = {},
doi = {10.1128/mBio.01080-19},
pmid = {31213555},
issn = {2150-7511},
}
@article {pmid31212792,
year = {2019},
author = {Cepas, V and López, Y and Gabasa, Y and Martins, CB and Ferreira, JD and Correia, MJ and Santos, LMA and Oliveira, F and Ramos, V and Reis, M and Castelo-Branco, R and Morais, J and Vasconcelos, V and Probert, I and Guilloud, E and Mehiri, M and Soto, SM},
title = {Inhibition of Bacterial and Fungal Biofilm Formation by 675 Extracts from Microalgae and Cyanobacteria.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {8},
number = {2},
pages = {},
doi = {10.3390/antibiotics8020077},
pmid = {31212792},
issn = {2079-6382},
support = {634588//Horizon 2020 Framework Programme/ ; },
abstract = {Bacterial biofilms are complex biological systems that are difficult to eradicate at a medical, industrial, or environmental level. Biofilms confer bacteria protection against external factors and antimicrobial treatments. Taking into account that about 80% of human infections are caused by bacterial biofilms, the eradication of these structures is a great priority. Biofilms are resistant to old-generation antibiotics, which has led to the search for new antimicrobials from different sources, including deep oceans/seas. In this study, 675 extracts obtained from 225 cyanobacteria and microalgae species (11 phyla and 6 samples belonging to unknown group) were obtained from different culture collections: The Blue Biotechnology and Ecotoxicology Culture Collection (LEGE-CC), the Coimbra Collection of Algae (ACOI) from Portugal, and the Roscoff Culture Collection (RCC) from France. The largest number of samples was made up of the microalgae phylum Chlorophyta (270) followed by Cyanobacteria (261). To obtain a large range of new bioactive compounds, a method involving three consecutive extractions (hexane, ethyl acetate, and methanol) was used. The antibiofilm activity of extracts was determined against seven different bacterial species and two Candida strains in terms of minimal biofilm inhibitory concentration (MBIC). The highest biofilm inhibition rates (%) were achieved against Candida albicans and Enterobacter cloacae. Charophyta, Chlorophyta, and Cyanobacteria were the most effective against all microorganisms. In particular, extracts of Cercozoa phylum presented the lowest MBIC50 and MBIC90 values for all the strains except C. albicans.},
}
@article {pmid31211205,
year = {2019},
author = {Heuschkel, I and Hoschek, A and Schmid, A and Bühler, B and Karande, R and Bühler, K},
title = {Data on mixed trophies biofilm for continuous cyclohexane oxidation to cyclohexanol using Synechocystis sp. PCC 6803.},
journal = {Data in brief},
volume = {25},
number = {},
pages = {104059},
doi = {10.1016/j.dib.2019.104059},
pmid = {31211205},
issn = {2352-3409},
abstract = {Photosynthetic microorganisms offer promising perspectives for the sustainable production of value-added compounds. Nevertheless, the cultivation of phototrophic organisms to high cell densities (HCDs) is hampered by limited reactor concepts. Co-cultivation of the photoautotrophic Synechocystis sp. PCC 6803 and the chemoheterotrophic P. taiwanensis VLB 120 enabled HCDs up to 51.8 gCDW L-1. Respective biofilms have been grown as a biofilm in capillary flow-reactors, and oxygen evolution, total biomass, as well as the ratio of the two strains, have been followed under various cultivation conditions. Furthermore, biofilm formation on a microscopic level was analyzed via confocal laser scanning microscopy using a custom made flow-cell setup. The concept of mixed trophies co-cultivation was coupled to biotransformation, namely the oxyfunctionalization of cyclohexane to cyclohexanol. For benchmarking, the performance of the phototrophic reaction was compared to the chemical process, and to a biotechnological approach using a heterotrophic organism only. The data presented refer to our research paper &quot;Mixed-species biofilms for high-cell-density application of Synechocystis sp. PCC 6803 in capillary reactors for continuous cyclohexane oxidation to cyclohexanol&quot; Hoschek et al., 2019.},
}
@article {pmid31209011,
year = {2019},
author = {Rodríguez López, AL and Lee, MR and Wang, NB and Dunn, KK and Sanchez, H and Raman, N and Andes, DR and Lynn, DM and Palecek, SP},
title = {Small-Molecule Morphogenesis Modulators Enhance the Ability of 14-Helical β-Peptides To Prevent Candida albicans Biofilm Formation.},
journal = {Antimicrobial agents and chemotherapy},
volume = {63},
number = {9},
pages = {},
doi = {10.1128/AAC.02653-18},
pmid = {31209011},
issn = {1098-6596},
abstract = {Candida albicans is an opportunistic fungal pathogen responsible for mucosal candidiasis and systemic candidemia in humans. Often, these infections are associated with the formation of drug-resistant biofilms on the surfaces of tissues or medical devices. Increased incidence of C. albicans resistance to current antifungals has heightened the need for new strategies to prevent or eliminate biofilm-related fungal infections. In prior studies, we designed 14-helical β-peptides to mimic the structural properties of natural antimicrobial α-peptides (AMPs) in an effort to develop active and selective antifungal compounds. These amphiphilic, cationic, helical β-peptides exhibited antifungal activity against planktonic C. albicans cells and inhibited biofilm formation in vitro and in vivo Recent studies have suggested the use of antivirulence agents in combination with antifungals. In this study, we investigated the use of compounds that target C. albicans polymorphism, such as 1-dodecanol, isoamyl alcohol, and farnesol, to attempt to improve β-peptide efficacy for preventing C. albicans biofilms. Isoamyl alcohol, which prevents hyphal formation, reduced the minimum biofilm prevention concentrations (MBPCs) of β-peptides by up to 128-fold. Combinations of isoamyl alcohol and antifungal β-peptides resulted in less than 10% hemolysis at the antifungal MBPCs. Overall, our results suggest potential benefits of combination therapies comprised of morphogenesis modulators and antifungal AMP peptidomimetics for preventing C. albicans biofilm formation.},
}
@article {pmid31207891,
year = {2019},
author = {Fu, TK and Ng, SK and Chen, YE and Lee, YC and Demeter, F and Herczeg, M and Borbás, A and Chiu, CH and Lan, CY and Chen, CL and Chang, MD},
title = {Rhamnose Binding Protein as an Anti-Bacterial Agent-Targeting Biofilm of Pseudomonas aeruginosa.},
journal = {Marine drugs},
volume = {17},
number = {6},
pages = {},
doi = {10.3390/md17060355},
pmid = {31207891},
issn = {1660-3397},
support = {MOST 103-2627-M-007-006//Ministry of Science and Technology/ ; MOST 107-0210-01-19-04//Ministry of Science and Technology/ ; GINOP-2.3.2-15-2016-00008//European Regional Development Fund/ ; ÚNKP-18-3 New National Excellence Program//Ministry of Human Capacities of Hungary/ ; },
abstract = {More than 80% of infectious bacteria form biofilm, which is a bacterial cell community surrounded by secreted polysaccharides, proteins and glycolipids. Such bacterial superstructure increases resistance to antimicrobials and host defenses. Thus, to control these biofilm-forming pathogenic bacteria requires antimicrobial agents with novel mechanisms or properties. Pseudomonas aeruginosa, a Gram-negative opportunistic nosocomial pathogen, is a model strain to study biofilm development and correlation between biofilm formation and infection. In this study, a recombinant hemolymph plasma lectin (rHPLOE) cloned from Taiwanese Tachypleus tridentatus was expressed in an Escherichia coli system. This rHPLOE was shown to have the following properties: (1) Binding to P. aeruginosa PA14 biofilm through a unique molecular interaction with rhamnose-containing moieties on bacteria, leading to reduction of extracellular di-rhamnolipid (a biofilm regulator); (2) decreasing downstream quorum sensing factors, and inhibiting biofilm formation; (3) dispersing the mature biofilm of P. aeruginosa PA14 to improve the efficacies of antibiotics; (4) reducing P. aeruginosa PA14 cytotoxicity to human lung epithelial cells in vitro and (5) inhibiting P. aeruginosa PA14 infection of zebrafish embryos in vivo. Taken together, rHPLOE serves as an anti-biofilm agent with a novel mechanism of recognizing rhamnose moieties in lipopolysaccharides, di-rhamnolipid and structural polysaccharides (Psl) in biofilms. Thus rHPLOE links glycan-recognition to novel anti-biofilm strategies against pathogenic bacteria.},
}
@article {pmid31207076,
year = {2019},
author = {Liang, D and Li, H and Xu, X and Liang, J and Dai, X and Zhao, W},
title = {Rational design of peptides with enhanced antimicrobial and anti-biofilm activities against cariogenic bacterium Streptococcus mutans.},
journal = {Chemical biology &amp; drug design},
volume = {},
number = {},
pages = {},
doi = {10.1111/cbdd.13579},
pmid = {31207076},
issn = {1747-0285},
support = {2018B030311047//the Science and Technology Department of Guangdong Province, China/ ; JCYJ20160428142231354//the Science and Technology Program of Shenzhen, China/ ; 201804010419//the Science and Technology Program of Guangzhou, China/ ; },
abstract = {Streptococcus mutans (S. mutans) is known to be a leading cariogenic pathogen in the oral cavity. Antimicrobial peptides possess excellent properties to combat such pathogens. In this study, we compared the antimicrobial activity of novel linear reutericin 6- and/or gassericin A-inspired peptides and identified LR-10 as the leading peptide. Antibacterial assays demonstrate that LR-10 is more active against S. mutans (3.3 μM) than many peptide-based agents without resistance selection, capable of killing many oral pathogens, and tolerant of physiological conditions. LR-10 also presented a faster killing rate than chlorhexidine and erythromycin, and appeared to display selective activity against S. mutans within 10 s. S. mutans is usually encased in plaque biofilms. Biofilm inhibitory assays indicated that LR-10 had excellent inhibitory effect on the biofilm formation of S. mutans and biofilm-encased cells in vitro at low concentrations (6.5 μM). Consistent with most peptides, LR-10 kills S. mutans mainly by disrupting the cell membranes. Notably, both hemolytic activity assays and cytotoxicity tests indicated that LR-10 could keep biocompatible at the effective concentrations. Hence, LR-10 could be a good candidate for clinical treatment of dental caries.},
}
@article {pmid31206966,
year = {2019},
author = {Melian, C and Segli, F and Gonzalez, R and Vignolo, G and Castellano, P},
title = {Lactocin AL705 as quorum sensing inhibitor to control Listeria monocytogenes biofilm formation.},
journal = {Journal of applied microbiology},
volume = {127},
number = {3},
pages = {911-920},
doi = {10.1111/jam.14348},
pmid = {31206966},
issn = {1365-2672},
support = {PICT2016, PICT2014//Agencia Nacional de Promoción Científica y Tecnológica/ ; 0585//Agencia Nacional de Promoción Científica y Tecnológica/ ; 441//Consejo Nacional de Investigaciones Científicas y Técnicas/ ; },
abstract = {AIMS: The control of Listeria monocytogenes biofilm formation using lactocin AL705 bacteriocin at sub-minimum inhibitory concentrations (MICs) through an antiquorum sensing strategy, was preliminarily investigated.<br><br>METHODS AND RESULTS: The screening for biofilm formation of different Listeria species at 10°C allowed selecting L. monocytogenes FBUNT for its use as biofilm producer. MIC and minimum bactericidal concentration of lactocin AL705 purified extract against the pathogen was determined. Bacteriocin sub-MICs were used to evaluate biofilm reduction. Concentrations between 2·5-20 AU ml-1 of lactocin AL705 produced significant decreases in biofilm formation without affecting the growth of the pathogen after 3 days of incubation. When bacteriocin concentrations (5-20 arbitrary units per millilitre (AU ml-1)) were investigated as quorum sensing (QS) inhibitors using Vibrio harveyi as reporter strain, a significant reduction in luminescence by lactocin AL705 (20 AU ml-1) was observed. Even when L. monocytogenes produced AI-2 like molecules as recognized by the reporter strain, bacteriocins did not interfere with this compound.<br><br>CONCLUSION: Antilisterial lactocin AL705 used to disrupt QS through a signal molecule inactivation was able to control L. monocytogenes FBUNT biofilm formation. Other molecule(s) different from the AI-2 involved during biofilm formation could be acting as target of the bacteriocin.<br><br>The use of bacteriocins derived from food-grade micro-organisms as a QS inhibition represents an effective strategy to control pathogens as well as an environmentally friendly sanitation method to mitigate postprocessing food contamination.},
}
@article {pmid31202712,
year = {2019},
author = {Zhao, Y and Liu, D and Huang, W and Yang, Y and Ji, M and Nghiem, LD and Trinh, QT and Tran, NH},
title = {Insights into biofilm carriers for biological wastewater treatment processes: Current state-of-the-art, challenges, and opportunities.},
journal = {Bioresource technology},
volume = {288},
number = {},
pages = {121619},
doi = {10.1016/j.biortech.2019.121619},
pmid = {31202712},
issn = {1873-2976},
abstract = {Biofilm carriers play an important role in attached growth systems for wastewater treatment processes. This study systematically summarizes the traditional and novel biofilm carriers utilized in biofilm-based wastewater treatment technology. The advantages and disadvantages of traditional biofilm carriers are evaluated and discussed in light of basic property, biocompatibility and applicability. The characteristics, applications performance, and mechanism of novel carriers (including slow-release carriers, hydrophilic/electrophilic modified carriers, magnetic carriers and redox mediator carriers) in wastewater biological treatment were deeply analyzed. Slow release biofilm carriers are used to provide a solid substrate and electron donor for the growth of microorganisms and denitrification for anoxic and/or anaerobic bioreactors. Carriers with hydrophilic/electrophilic modified surface are applied for promoting biofilm formation. Magnetic materials-based carriers are employed to shorten the start-up time of bioreactor. Biofilm carriers acting as redox mediators are used to accelerate biotransformation of recalcitrant pollutants in industrial wastewater.},
}
@article {pmid31202424,
year = {2019},
author = {Moraes, JO and Cruz, EA and Pinheiro, Í and Oliveira, TCM and Alvarenga, V and Sant'Ana, AS and Magnani, M},
title = {An ordinal logistic regression approach to predict the variability on biofilm formation stages by five Salmonella enterica strains on polypropylene and glass surfaces as affected by pH, temperature and NaCl.},
journal = {Food microbiology},
volume = {83},
number = {},
pages = {95-103},
doi = {10.1016/j.fm.2019.04.012},
pmid = {31202424},
issn = {1095-9998},
abstract = {This study assessed the adhesion and formation of biofilm by five Salmonella enterica strains (S. Enteritidis 132, S. Infantis 176, S. Typhimurium 177, S. Heidelberg 281 and S. Corvallis 297) on polypropylene (PP) and glass (G) surfaces as affected by pH (4-7), NaCl concentration (0-10% w/v) and temperature (8-35 °C). Sessile counts <3 log CFU/cm2 were considered lack of adhesion (category 1), while counts ≥ 3 and < 5 log CFU/cm2 corresponded to adhesion (category 2) and counts ≥ 5 log CFU/cm2 corresponded biofilm formation (category 3). The obtained results categorized in these three responses were used to develop ordinal regression models to predict the probability of biofilm stages on PP- and G-surfaces. The experimental outcomes for lack of adhesion were >90% on PP- and G-surfaces. Generally, adhesion outcomes corresponded to approximately 36% of the total, whereas biofilm outcomes were close to 65% in both PP- and G-surfaces. The biofilm stages varied among the strains studied and with the material surface under the same experimental conditions. According to the generated ordinal models, the probability of adhesion and biofilm formation on PP-surface by the five S. enterica strains tested decreased at pH 4 or 5 in NaCl concentrations >4% and at a temperature <20 °C. On G-surface, the probability of adhesion increased pH 6 or 7, in the absence of NaCl and temperatures <20 °C, while, the probability of biofilm formation increased in the same pH, NaCl concentration up to 4% and temperatures ≥20 °C. This is the first study assessing the biofilm formation through categorical, ordinal responses and it shows that ordinal regression models can be useful to predict biofilm stages of S. enterica as a function of pH, NaCl, and temperature or their interactions.},
}
@article {pmid31202413,
year = {2019},
author = {García-Sánchez, L and Melero, B and Jaime, I and Rossi, M and Ortega, I and Rovira, J},
title = {Biofilm formation, virulence and antimicrobial resistance of different Campylobacter jejuni isolates from a poultry slaughterhouse.},
journal = {Food microbiology},
volume = {83},
number = {},
pages = {193-199},
doi = {10.1016/j.fm.2019.05.016},
pmid = {31202413},
issn = {1095-9998},
abstract = {The fastidious requirement of the zoonotic pathogen Campylobacter jejuni contrasts with its ability to overcome harsh conditions. Different strategies might be involved in the survival and persistence of C. jejuni through the poultry food chain. Therefore, the aims of this study were to get insights in the survival strategies in the poultry slaughterhouse environment by (i) characterizing factors such as biofilm formation, virulence and antimicrobial resistance in environmental isolates and (ii) understanding the possible link between the phenotypic and genetic characterization using whole genome sequencing (WGS). Results have shown that three STs: ST 443 (PFGE A), ST 904 (PFGE C) and ST 3769 (PFGE G), out of the six studied, formed biofilms with variable intensity according to different conditions (temperatures -37 °C, 30 °C, 25°C- and materials -stainless steel and plastic-). High levels of antimicrobial resistance were found in isolates to ciprofloxacin, nalidixic acid and tetracycline as well as to two common detergents used in the slaughterhouse. A combination of several changes in the genome of ST 904 (PFGE C) including mutations, insertions in antimicrobial resistance genes, the presence of T6SS and a set of genes related to virulence factors might explain its ability to form biofilm and persist longer in the environment. However, the complexity of the survival strategies adopted by the different strains of C. jejuni suggests that multiple mechanisms may exist that allow these organisms to persist and ultimately cause disease in humans.},
}
@article {pmid31200347,
year = {2019},
author = {Dawas, A and Abu-Salih, S and Sabbah, I and Nejidat, A and Dosoretz, CG},
title = {Controlling nitritation in a continuous split-feed/aeration biofilm nitrifying bioreactor.},
journal = {Bioresource technology},
volume = {288},
number = {},
pages = {121599},
doi = {10.1016/j.biortech.2019.121599},
pmid = {31200347},
issn = {1873-2976},
abstract = {This study explored the stability of partial ammonium oxidation at low feed concentration (50 g N/m3), suitable for anammox process, in continuous fixed bed up-flow biofilm reactors with external recirculation-aeration. The reactors, filled with crushed basalt, were fed with synthetic medium at 20-25 °C at constant flow-rate with limiting dissolved oxygen concentration controlled by the recirculation ratio (R). Successful nitritation was achieved at R ≅ 4-6 with approx. 50% of NH4+ oxidized to NO2- with <5% NO3-accumulation. q-PCR analysis along the reactor showed ammonia oxidizing bacteria being the prevalent nitrifiers over the three-fourths of the bed in the flow direction, negligible denitrifiers and absent ammonium oxidizing archaea. A numerical model for predicting the concentration of the nitrogen species and DO was formulated. The model successfully predicted the experimental results and displayed good sensitivity to intrinsic oxygen uptake parameters. The proposed numerical model can serve both as an operational and design tool.},
}
@article {pmid31198058,
year = {2019},
author = {Manilal, A and Shewangizaw, M and Mama, M and Gezmu, T and Merdekios, B},
title = {Methicillin-resistant Staphylococcus aureus colonization in HIV patients of Arba Minch province, Ethiopia: Carriage rates, antibiotic resistance, and biofilm formation.},
journal = {Acta microbiologica et immunologica Hungarica},
volume = {},
number = {},
pages = {1-15},
doi = {10.1556/030.66.2019.014},
pmid = {31198058},
issn = {1588-2640},
abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a significant opportunistic pathogen among human immunodeficiency virus (HIV) patients of Ethiopia. This study aimed at delineating the prevalence, antimicrobial resistance, and biofilm-forming potentials of nasally colonized MRSA among HIV patients in the Arba Minch province of Ethiopia. A cross-sectional study was performed in HIV patients who visit anti-retroviral therapy clinic of the Arba Minch Hospital between February and April 2017. Nasal samples were collected and inspected for Staphylococcus following standard procedures. MRSA was identified using cefoxitin disk and antibiotics sensitivity test was performed as per Kirby-Baur disk diffusion method. The formation of biofilm was inspected using both qualitative and quantitative methods. A total of 307 HIV patients were examined. The overall prevalence of S. aureus was found to be 39.7%. The prevalence of MRSA was 20.8%. The rate of nasal colonization of MRSA was relatively higher among females. In bivariate analysis, MRSA colonization was statistically significant in patients with CD4 count ≤350 (p value = 0.002) and co-trimoxazole prophylaxis (p value = 0.003). Concomitant resistance to erythromycin, tetracycline, and co-trimoxazole were 48.4%, 45.3%, and 39.0%, respectively. Invariably, all MRSA isolates were 100% sensitive to vancomycin. Of the 64 MRSA isolates, 18.7% were considered as multidrug-resistant. The rate of biofilm formation was 34.3%. The results revealed a high prevalence rate in the nasal colonization of MRSA in HIV patients.},
}
@article {pmid31198057,
year = {2019},
author = {Shivaee, A and Mohammadzadeh, R and Shahbazi, S and Pardakhtchi, E and Ohadi, E and Kalani, BS},
title = {Time-variable expression levels of mazF, atlE, sdrH, and bap genes during biofilm formation in Staphylococcus epidermidis.},
journal = {Acta microbiologica et immunologica Hungarica},
volume = {},
number = {},
pages = {1-10},
doi = {10.1556/030.66.2019.019},
pmid = {31198057},
issn = {1588-2640},
abstract = {Staphylococcus epidermidis is an opportunistic pathogen causing infections related to the usage of implants and medical devices. Pathogenicity of this microorganism is mainly linked to its capability to form biofilm structures. Biofilm formation vastly depends on several factors including different proteins. We studied the expression levels of three proteins including SdrH, Bap, AtlE, and MazF at different time intervals during the course of biofilm formation. In this study, a catheter-derived S. epidermidis isolate with strong ability of biofilm formation was selected. PCR assay was used to detect sdrH, bap, atlE, and mazF genes in this isolate. Real-time PCR was used to determine the expression levels of these genes after 4, 8, and 20 h during the course of biofilm formation. The studied genes showed different expression levels at different time intervals during biofilm formation by real-time PCR method. Expression levels of atlE and sdrH genes were the highest at 4 h, whereas bap gene showed the highest expression level at 8 h during the course of biofilm formation. In addition, the expression level of mazF gene peaked at 4 h and then progressively decreased at 8 and 20 h. Our results suggest the importance of AtlE, SdrH, and MazF proteins in the establishment and development of the biofilm structure. In addition, our results showed the important role of protein Bap in the accumulation of biofilm structure. Future studies are required to understand the exact role of MazF in the process of biofilm formation.},
}
@article {pmid31197408,
year = {2019},
author = {Ariafar, MN and Iğci, N and Akçelik, M and Akçelik, N},
title = {Investigation of the effect of different environmental conditions on biofilm structure of Salmonella enterica serotype Virchow via FTIR spectroscopy.},
journal = {Archives of microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00203-019-01681-5},
pmid = {31197408},
issn = {1432-072X},
abstract = {This study aims to describe the content of polymeric matrix components under different incubation temperatures and pH levels. Optimal biofilm production of 15 S. Virchow isolates occurred following the incubation in LB-NaCl for 72 h, at pH 6.6 and 20 °C. The expression of csgA, csgD, adrA and bcsA genes at 20 °C, 25 °C and 30 °C in S. Virchow DMC18 was analyzed, and it was discovered that the maximum production of cellulose and curli fimbriae occurred at 20 °C. The physical characteristics of pellicle structure of S. Virchow DMC18 was determined as rigid at 20 °C, while becoming fragile at higher temperatures. FTIR analyses confirmed the obtained molecular findings. The intensities of the 16 different peaks originating from carbohydrate, protein, and nucleic acid in the spectra of biofilm samples significantly diminished (p < 0.05) with the increasing temperature. The highest intensities of lipids and carbohydrates were observed at 20 °C indicating the changes in cell surface properties.},
}
@article {pmid31195653,
year = {2019},
author = {Zhou, Y and Gao, X},
title = {Characterization of Biofilm Formed by Phenanthrene-Degrading Bacteria on Rice Root Surfaces for Reduction of PAH Contamination in Rice.},
journal = {International journal of environmental research and public health},
volume = {16},
number = {11},
pages = {},
doi = {10.3390/ijerph16112002},
pmid = {31195653},
issn = {1660-4601},
abstract = {One effective method in to reduce the uptake of organic contaminants by plants is the development of a root barrier. In this study, the characterization of biofilm structure and function by phenanthrene-degrading Pseudomonas sp. JM2-gfp on rice root surfaces were carried out. Our results showed that root surfaces from three rice species, namely Liaojing401, Koshihikari, and Zhenzhuhong all present hydrophobicity and a high initial adhesion of strain JM2-gfp. Matured robust biofilm formation occurred at 48 h on the root surfaces. The biofilm exhibited cell dense aggregates and biomass embedded in the extracellular polymeric substance (EPS) matrix. EPS composition results showed that the proteins, carbohydrates, lipids and nucleic acids are produced in the biofilm, while the content varied with rice species. Under the initial concentration of phenanthrene 50 mg·L-1, the residual phenanthrene in plant roots from 'Zhengzhuhong', 'Koshihikari' and 'Liaojing401' with biofilm mediated were significantly decreased by 71.9%, 69.3% and 58.7%, respectively, compared to those without biofilm groups after 10 days of exposure. Thus, the biofilm colonized on roots plays an important role of degradation in order to reduce the level of phenanthrene uptake of plants. Thereby, the present work provides significant new insights into lowering the environmental risks of polycyclic aromatic hydrocarbons (PAHs) in crop products from contaminated agriculture soils.},
}
@article {pmid31195361,
year = {2019},
author = {Zheng, M and Zhu, H and Han, Y and Xu, C and Zhang, Z and Han, H},
title = {Comparative investigation on carbon-based moving bed biofilm reactor (MBBR) for synchronous removal of phenols and ammonia in treating coal pyrolysis wastewater at pilot-scale.},
journal = {Bioresource technology},
volume = {288},
number = {},
pages = {121590},
doi = {10.1016/j.biortech.2019.121590},
pmid = {31195361},
issn = {1873-2976},
abstract = {By regulating the extraction solvent and alkali in pretreatment, two carbon-based MBBRs were compared in pilot-scale to synchronously remove phenols and ammonia of coal pyrolysis wastewater (CPW) under fluctuant phenols-ammonia loadings. It revealed that lignite activated coke (LAC)-based MBBR performed more stable with phenols increasing (250-550 mg/L), and reached higher tolerance limit to ammonia (>320 mg/L) than activated carbon (AC)-based MBBR under fluctuant ammonia loadings. During the phenols-ammonia synchronous removal process, the LAC provided the firm basis for shock resistance due to superior resilient adsorption capacity, enhanced sludge property and microbial cooperation. Furthermore, microbial analysis revealed that the strengthened collaboration between archaea and facultative bacteria played the primary role in phenols-ammonia synchronous degradation. Specifically, the heterotrophic bacteria consumed phenols-ammonia by partial nitrification process and ammonia assimilation, following by denitrifying process to further eliminate phenols. The multifunctional Comamonas was the critical genus participating in all procedures.},
}
@article {pmid31194941,
year = {2019},
author = {Zeng, R and Xu, H and Liu, Y and Du, L and Duan, Z and Tong, J and He, Y and Chen, Q and Chen, X and Li, M},
title = {miR-146a Inhibits Biofilm-Derived Cutibacterium acnes-Induced Inflammatory Reactions in Human Keratinocytes.},
journal = {The Journal of investigative dermatology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jid.2019.03.1161},
pmid = {31194941},
issn = {1523-1747},
abstract = {Acne is a chronic inflammatory skin disorder that often involves the formation of Cutibacterium acnes (C. acnes) biofilms. Several microRNAs (miRNAs) are known to be involved in inflammatory responses. However, it is unknown whether miRNAs play a role in the inflammatory reaction triggered by C. acnes biofilm. In this study, we investigated the role of miR-146a in biofilm-derived C. acnes-induced inflammatory responses. Increased expressions of miR-146a and toll-like receptor (TLR) 2 were detected in acne lesions. In the presence of biofilm-derived C. acnes, TLR2 and its downstream NF-kB and MAPK pathways were activated in keratinocytes. Subsequently, miR-146a was upregulated in these cells along with the induction of IL-6, IL-8, and tumor necrosis factor (TNF)-α. Furthermore, our data indicates that miR-146a could directly bind the 3'-untranslated region of IRAK1 and TNF receptor-associated factor 6 (TRAF6) and suppress their expression, leading to an inhibition of biofilm-derived C. acnes-induced activation of NF-kB, p38, and ERK1/2 pathways. Overall, our results indicate that biofilm-derived C. acnes induces miR-146a, which can downregulate the production of IL-6, -8, and TNF-α in acne inflammation by inhibiting the TLR2/IRAK1/TRAF6/NF-κB and MAPK pathways.},
}
@article {pmid31194008,
year = {2018},
author = {Sanawar, H and Pinel, I and Farhat, NM and Bucs, SS and Zlopasa, J and Kruithof, JC and Witkamp, GJ and van Loosdrecht, MCM and Vrouwenvelder, JS},
title = {Enhanced biofilm solubilization by urea in reverse osmosis membrane systems.},
journal = {Water research X},
volume = {1},
number = {},
pages = {100004},
doi = {10.1016/j.wroa.2018.10.001},
pmid = {31194008},
issn = {2589-9147},
abstract = {Chemical cleaning is routinely performed in reverse osmosis (RO) plants for the regeneration of RO membranes that suffer from biofouling problems. The potential of urea as a chaotropic agent to enhance the solubilization of biofilm proteins has been reported briefly in the literature. In this paper the efficiency of urea cleaning for RO membrane systems has been compared to conventionally applied acid/alkali treatment. Preliminary assessment confirmed that urea did not damage the RO polyamide membranes and that the membrane cleaning efficiency increased with increasing concentrations of urea and temperature. Accelerated biofilm formation was carried out in membrane fouling simulators which were subsequently cleaned with (i) 0.01M sodium hydroxide (NaOH) and 0.1M hydrochloric acid (HCl) (typically applied in industry), (ii) urea (CO(NH2)2) and hydrochloric acid, or (iii) urea only (1340 g/Lwater). The pressure drop over the flow channel was used to evaluate the efficiency of the applied chemical cleanings. Biomass removal was evaluated by measuring chemical oxygen demand (COD), adenosine triphosphate (ATP), protein, and carbohydrate content from the membrane and spacer surfaces after cleaning. In addition to protein and carbohydrate quantification of the extracellular polymeric substances (EPS), fluorescence excitation-emission matrix (FEEM) spectroscopy was used to distinguish the difference in organic matter of the remaining biomass to assess biofilm solubilization efficacy of the different cleaning agents. Results indicated that two-stage CO(NH2)2/HCl cleaning was as effective as cleaning with NaOH/HCl in terms of restoring the feed channel pressure drop (>70% pressure drop decrease). One-stage cleaning with urea only was not as effective indicating the importance of the second-stage low pH acid cleaning in weakening the biofilm matrix. All three chemical cleaning protocols were equally effective in reducing the concentration of predominant EPS components protein and carbohydrate (>50% reduction in concentrations). However, urea-based cleaning strategies were more effective in solubilizing protein-like matter and tyrosine-containing proteins. Furthermore, ATP measurements showed that biomass inactivation was up to two-fold greater after treatment with urea-based chemical cleanings compared to the conventional acid/alkali treatment. The applicability of urea as an alternative, economical, eco-friendly and effective chemical cleaning agent for the control of biological fouling was successfully demonstrated.},
}
@article {pmid31193536,
year = {2019},
author = {Gomes, F and Martins, N and Ferreira, ICFR and Henriques, M},
title = {Anti-biofilm activity of hydromethanolic plant extracts against Staphylococcus aureus isolates from bovine mastitis.},
journal = {Heliyon},
volume = {5},
number = {5},
pages = {e01728},
doi = {10.1016/j.heliyon.2019.e01728},
pmid = {31193536},
issn = {2405-8440},
abstract = {Bovine mastitis (BM) presents a high incidence, being Staphylococcus aureus one of the major causative agents. Antibiotics comprise the most common therapeutic approach, but due to their indiscriminate use, high rates of increasingly resistant bacterial species have been markedly pointed out. Particularly, S. aureus possesses a pronounced ability to form biofilms, and therefore, are of pivotal interest due to its alarming pathogenicity. The present study investigates the antibacterial properties of Eucalyptus globulus methanol: water extracts, alone and in combination with Juglans regia, against S. aureus isolates from BM. All isolates and reference strain proved to be good biofilm producers after 24 h of bacterial growth. Individually, the studied plant extracts (PE) lead to a considerable biofilm cells reduction, but their combination revealed to be the most effective strategy. When tested in combination, both extracts led to a 3 and 5 log reduction for S. aureus ATCC 25923 and S. aureus 1, respectively. Based on these findings, both PE seem to be promissory antimicrobial agents for upcoming use on dairy industry contaminations, BM and even S. aureus-triggered food poisoning. Further studies are needed to understand which of the compounds present in the extracts are responsible for the observed effects, including their corresponding modes of action.},
}
@article {pmid31193467,
year = {2019},
author = {Singhal, N and Maurya, AK and Singh, NS and Kumar, M and Virdi, JS},
title = {Antimicrobial resistance and its relationship with biofilm production and virulence-related factors in Yersinia enterocolitica biotype 1A.},
journal = {Heliyon},
volume = {5},
number = {5},
pages = {e01777},
doi = {10.1016/j.heliyon.2019.e01777},
pmid = {31193467},
issn = {2405-8440},
abstract = {The aim of the present study was to determine antimicrobial susceptibilities, biofilm production and, to discern a relationship between antimicrobial resistance, biofilm potential and virulence-related genes in strains of Yersinia entercocolitica biotype 1A. Thirty strains of Y. enterocolitica biotype 1A including clinical and non-clinical strains were investigated. Antimicrobial susceptibility for 15 antibiotics (representing different classes) was determined by disk-diffusion assay. Biofilm potential was determined on two different culture media using crystal violet assay. Also, a co-relation was studied between antimicrobial susceptibilities, biofilm production and virulence-related genes. All strains of biotype 1A produced biofilms and exhibited varied level of susceptibilities for different antibiotics. More than 60% of the strains were strong to moderate biofilm producers and, were exclusively associated with REP/ERIC clonal group B. Moderate and strong biofilm producers exhibited both sensitive and resistant phenotypes towards different antibiotics. Interestingly, weak biofilm producers were resistant to amoxicillin, amoxicillin-clavulanate and cefazolin. Analysis of antimicrobial susceptibilities, biofilm potential and virulence-related genes did not reveal any unequivocal relationships. The differential biofilm potential of Indian strains of Y. enterocolitica biotype 1A, suggests that biotype 1A strains are heterogeneous in nature.},
}
@article {pmid31191696,
year = {2019},
author = {Zaatout, N and Ayachi, A and Kecha, M},
title = {Interaction of primary mammary bovine epithelial cells with biofilm-forming staphylococci associated with subclinical bovine mastitis.},
journal = {Iranian journal of veterinary research},
volume = {20},
number = {1},
pages = {27-32},
pmid = {31191696},
issn = {1728-1997},
abstract = {Background: Staphylococci are recognized worldwide as one of the most important etiological agents of bovine mastitis due to their virulence factors such as their ability to penetrate inside mammary epithelial cells and their ability to form biofilm.<br><br>Aims: The objectives of this study were to establish a model of primary mammary epithelial cells originating from the secretory tissue of the bovine udder in order to evaluate the invasion ability of 42 staphylococci isolated from subclinical bovine mastitis cases.<br><br>Methods: Two techniques were used to establish a model of primary mammary epithelial cells, the explant technique and the enzymatic method. Biofilm formation was detected using a quantitative spectrophotometric assay. When compared with the enzymatic digestion method, the epithelial cells obtained by the explant technique grew faster and reached quickly to confluence.<br><br>Results: The results showed that 60% of Staphylococcus aureus isolates (n=12) were able to invade the epithelial cells and 72.7% of coagulase negative staphylococci (CNS) isolates were invasive (n=16). Staphylococcus xylosus isolates showed higher invasion values compared to S. aureus isolates and non-biofilm forming staphylococci were able to invade primary epithelial cells, but no significant difference was found between the internalization capabilities of biofilm positive and negative isolates.<br><br>Conclusion: The results show that the explant technique is a valuable method for developing primary epithelial cells without damaging the cells, and provides new insights regarding the ability of staphylococci to penetrate inside primary mammary epithelial cells.},
}
@article {pmid31190904,
year = {2019},
author = {Navidifar, T and Amin, M and Rashno, M},
title = {Effects of sub-inhibitory concentrations of meropenem and tigecycline on the expression of genes regulating pili, efflux pumps and virulence factors involved in biofilm formation by Acinetobacter baumannii.},
journal = {Infection and drug resistance},
volume = {12},
number = {},
pages = {1099-1111},
doi = {10.2147/IDR.S199993},
pmid = {31190904},
issn = {1178-6973},
abstract = {Background: Sub-minimal inhibitory concentrations of antibiotics have been indicated to affect the biofilm formation in pathogens of nosocomial infections. This study aimed to investigate the effects of meropenem and tigecycline at their sub-minimum inhibitory concentrations (MICs) on the biofilm formation capacity of Acinetobacter baumannii (A. baumannii), as well as the expression levels of genes involved in biofilm formation, quorum sensing, pili assembly and efflux pumps. Materials and methods: In this study, four non-clonal strains (AB10, AB13, AB32 and AB55), which were different from the aspects of antibiotic susceptibility and biofilm formation from each other were selected for the evaluation of antimicrobial susceptibility, biofilm inducibility at sub-MICs of meropenem and tigecycline and the gene expression levels (the abaI, abaR, bap, pgaA, csuE, bfmS, bfmR, ompA, adeB, adeJ and adeG genes). Result: A significant increase in the MICs of all antibiotics was demonstrated in the biofilm cells in each four strains. The biofilm formation was significantly decreased in all the representative strains exposed to tigecycline. However, the biofilm inducibility at sub-MICs of meropenem was dependent on strain genotype. In concordance with these results, Pearson correlation analysis indicated a positive significant correlation between the biofilm formation capacity and the mRNA levels of genes encoding efflux pumps except adeJ, the genes involved in biofilm formation, pili assembly and quorum sensing following exposure to meropenem and tigecycline at their sub-MICs. Conclusion: These results revealed valuable data into the correlation between the gene transcription levels and biofilm formation, as well as quorum sensing and their regulation at sub-MICs of meropenem and tigecycline.},
}
@article {pmid31188854,
year = {2019},
author = {Meza-Villezcas, A and Gallego-Hernández, AL and Yildiz, FH and Jaime-Acuña, OE and Raymond-Herrera, O and Huerta-Saquero, A},
title = {Effect of antimicrobial nanocomposites on Vibrio cholerae lifestyles: Pellicle biofilm, planktonic and surface-attached biofilm.},
journal = {PloS one},
volume = {14},
number = {6},
pages = {e0217869},
doi = {10.1371/journal.pone.0217869},
pmid = {31188854},
issn = {1932-6203},
abstract = {Vibrio cholerae is an important human pathogen causing intestinal disease with a high incidence in developing countries. V. cholerae can switch between planktonic and biofilm lifestyles. Biofilm formation is determinant for transmission, virulence and antibiotic resistance. Due to the enhanced antibiotic resistance observed by bacterial pathogens, antimicrobial nanomaterials have been used to combat infections by stopping bacterial growth and preventing biofilm formation. In this study, the effect of the nanocomposites zeolite-embedded silver (Ag), copper (Cu), or zinc (Zn) nanoparticles (NPs) was evaluated in V. cholerae planktonic cells, and in two biofilm states: pellicle biofilm (PB), formed between air-liquid interphase, and surface-attached biofilm (SB), formed at solid-liquid interfaces. Each nanocomposite type had a distinctive antimicrobial effect altering each V. cholerae lifestyles differently. The ZEO-AgNPs nanocomposite inhibited PB formation at 4 μg/ml, and prevented SB formation and eliminated planktonic cells at 8 μg/ml. In contrast, the nanocomposites ZEO-CuNPs and ZEO-ZnNPs affect V. cholerae viability but did not completely avoid bacterial growth. At transcriptional level, depending on the nanoparticles and biofilm type, nanocomposites modified the relative expression of the vpsL, rbmA and bap1, genes involved in biofilm formation. Furthermore, the relative abundance of the outer membrane proteins OmpT, OmpU, OmpA and OmpW also differs among treatments in PB and SB. This work provides a basis for further study of the nanomaterials effect at structural, genetic and proteomic levels to understand the response mechanisms of V. cholerae against metallic nanoparticles.},
}
@article {pmid31187657,
year = {2019},
author = {Salman, M and Rizwana, R and Khan, H and Munir, I and Hamayun, M and Iqbal, A and Rehman, A and Amin, K and Ahmed, G and Khan, M and Khan, A and Amin, FU},
title = {Synergistic effect of silver nanoparticles and polymyxin B against biofilm produced by Pseudomonas aeruginosa isolates of pus samples in vitro.},
journal = {Artificial cells, nanomedicine, and biotechnology},
volume = {47},
number = {1},
pages = {2465-2472},
doi = {10.1080/21691401.2019.1626864},
pmid = {31187657},
issn = {2169-141X},
abstract = {Pseudomonas aeruginosa (P. aeruginosa) is an aerobic gram-negative, non-spore forming, rod-shaped bacterium. It accelerates the decline in lung function and ultimately leads to increased mortality and morbidity rate. Survival and virulence of P. aeruginosa is due to its biofilm formation ability. The main aim of this study was to test the synergistic effect of silver nanoparticles (AgNPs) in combination with Polymyxin B against biofilms of P. aeruginosa. A total of 500 pus aspirations were collected and bacterial pathogens were identified. Biofilm formation was attained using a glass tube method and microtiter plate assay. The minimum inhibitory concentration of Polymyxin B was determined using agar well diffusion method. Silver nanoparticles were synthesized by chemical reduction method followed by determination of their anti-pseudomonal ability separately and in combination with Polymyxin B using microtiter plate assay. Our results showed that 120 out of 500 samples were Pseudomonas positive. The ratio of multidrug-resistant (MDR) in our collected Pseudomonas samples was 83% (25/30). Generally, the minimum inhibitory concentration (MIC) of Polymyxin B was 16 µg/mL and that of AgNPs was null. However, AgNPs showed great synergistic effect in combination with Polymyxin B. Synergistically, the efficacy of Polymyxin B was enhanced four times as compared to unaided Polymyxin B.},
}
@article {pmid31187647,
year = {2019},
author = {Alavi, M and Karimi, N},
title = {Ultrasound assisted-phytofabricated Fe3O4 NPs with antioxidant properties and antibacterial effects on growth, biofilm formation, and spreading ability of multidrug resistant bacteria.},
journal = {Artificial cells, nanomedicine, and biotechnology},
volume = {47},
number = {1},
pages = {2405-2423},
doi = {10.1080/21691401.2019.1624560},
pmid = {31187647},
issn = {2169-141X},
abstract = {Complicated issue in infectious illnesses therapy is increasing of multidrug resistant (MDR) bacteria and biofilms in bacterial infections. In this way, emerging of nanotechnology as a new weapon specifically in the cases of metal nanoparticle (MNPs) synthesis and MNPs surface modification has obtained more attention. In this study, ultrasound-assisted green synthesis method was utilized for the preparation of Fe3O4 NPs with novel shape (dendrimer) through leaf aqueous extract of Artemisia haussknechtii Boiss. Ultraviolet-visible spectroscopy, energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), atomic force microscopic (AFM), X-ray diffraction (XRD) techniques were applied for MNPs physicochemical characterization. Also, disc diffusion assay, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), planktonic and biofilm morphology of three pathogenic bacteria involving Serratia marcescens ATCC 13880, Escherichia coli ATCC 25922, and methicillin-resistant Staphylococcus aureus (MRSA) were evaluated upon treatment of Fe3O4 NPs as antiplanktonic and antibiofilm analysis. Results showed efficient antiplanktonic and antibiofilm activities of biosynthesized Fe3O4 NPs with average diameter size of 83.4 nm. Reduction in biofilm formation of S. aureus ATCC under Fe3O4 NPs stress was significant (66%) in higher MNPs concentration (100 μg/mL). In addition, as first report, spreading ability of S. aureus as important factor in colony expansion on culture medium was reduced by increasing of Fe3O4 NPs. Present study demonstrates striking antiplanktonic, antibiofilm, antispreading mobility and antioxidant aspects of one-pot biosynthesized Fe3O4 NPs with novel shape.},
}
@article {pmid31187383,
year = {2019},
author = {García-Rodríguez, JP and Amezquita-Garcia, HJ and Escamilla-Alvarado, C and Rangel-Mendez, JR and Gutiérrez-García, K},
title = {Biofilm microbial composition changes due to different surface chemical modifications of activated carbon cloths in the biotransformation of 4-nitrophenol.},
journal = {Biodegradation},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10532-019-09880-z},
pmid = {31187383},
issn = {1572-9729},
support = {CVU: 781364//Consejo Nacional de Ciencia y Tecnología, CONACYT/ ; IT606-18//PAICYT 2018/ ; UANL-CA-385//PRODEP/ ; },
abstract = {Activated carbon cloths (ACCs) were used as biofilms supports in the anaerobic biotransformation of 4-nitrophenol (4NP). As received ACC material (AW) was oxidized with HNO3 (OX) and then functionalized with anthraquinone-2,6-disulfonate (AQ). The three ACCs were packed in hybrid UASB reactors and seeded with anaerobic granular sludge for biotransformation experiments. The results indicated that ACC-packed bioreactors improved the biotransformation of 4NP by twofold as compared to the control reactor without support materials. However, the biotransformation effciency of AW, OX and AQ was very similar (59%), indicating the role of ACC as biofilm support and not as redox mediator. After 4NP biotransformation several physicochemical and biological changes were observed like (1) the point of zero charge (pHPZC) shift from acidic values (AW = 5.0, OX = 3.4, AQ = 3.1) to neutral values (pHPZC = 7.6 on average), (2) increase in the concentration of acidic and basic surface functional groups over ACC materials and the amount of supported biomass on ACCs due to biofilm formation, and (3) enrichment of exoelectrogenic microorganisms belonging to the genera Geobacter over carbonyl-rich ACC surface as revealed by 16S rRNA amplicon sequencing. Overall, the results suggest that chemical modifications of ACCs changed the microbial composition of the biofilm, but the higher concentration of carbonyl groups on ACC did not affect the biotransformation of 4NP.},
}
@article {pmid31187378,
year = {2019},
author = {Zou, H and Wang, Y},
title = {Functional collaboration of biofilm-cathode electrode and microbial fuel cell for biodegradation of methyl orange and simultaneous bioelectricity generation.},
journal = {Environmental science and pollution research international},
volume = {26},
number = {22},
pages = {23061-23069},
doi = {10.1007/s11356-019-05617-w},
pmid = {31187378},
issn = {1614-7499},
support = {1604f0704047//Research Items from the Department of Science and Technology of Anhui Province, China/ ; gxyqZD2016212//Special Foundation for Young Scientists of Anhui province, China/ ; },
abstract = {A distinctive process (BCE-MFC) was developed to explore the methyl orange (MO) degradation and simultaneous bioelectricity generation based on the functional collaboration of biofilm, electrolysis, constructed wetland, and microbial fuel cell. The biofilm-cathode electrode-microbial fuel cell (BCE-MFC) was capable of sustaining an excellent MO removal (100%) and bioelectricity production (0.63 V). BCE significantly enhanced MO biodegradability, thus resulting in a 56.3% improvement of COD removal in subsequent MFC. Bacillus was dominant in biofilm on cathode in BCE. In MFC, Proteobacteria phylum (64.84%) and Exiguobacterium genus (13.30%) were predominated in the anode region, probably basically responsible for electricity generation. Interestingly, relatively high content of Heliothrix sp. (9.94%) was found in the MFC designed here, which was likely to participate in electricity production as well. The proposed functional collaboration may be an effective strategy in refractory wastewater treatment and power production.},
}
@article {pmid31187338,
year = {2019},
author = {Devadas, SM and Nayak, UY and Narayan, R and Hande, MH and Ballal, M},
title = {2,5-Dimethyl-4-hydroxy-3(2H)-furanone as an Anti-biofilm Agent Against Non-Candida albicans Candida Species.},
journal = {Mycopathologia},
volume = {184},
number = {3},
pages = {403-411},
doi = {10.1007/s11046-019-00341-y},
pmid = {31187338},
issn = {1573-0832},
abstract = {BACKGROUND: The predominance of non-Candida albicans Candida (NCAC) species causing healthcare-associated infections has increased over the last decade pertaining to their ability to form biofilms on medical devices. These biofilm-associated infections are challenging to treat as they are resistant to antifungal agents and evade host-immune response resulting in a high risk of device failure or biomaterial removal. Thus, to minimize the risk of biofilm-associated infections, preventing biofilm formation is the best approach which is mediated by the quorum quenching process.<br><br>METHODS: The present study investigated the modulatory effect of 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) on NCAC biofilm formation and also assessed the effect of the DMHF-coated catheters on biofilm formation of NCAC. The NCAC isolates studied were Candida tropicalis, Candida glabrata and Candida krusei isolated from catheter tip, urine and blood, respectively.<br><br>RESULTS: DMHF at a concentration of 30 µg/mL showed an inhibitory effect against NCAC biofilms at various stages and was statistically significant (p ≤ 0.05) against the various concentrations (50-5 µg/mL) tested and also among the three phases of experiment. The furanone content on coated catheters ranged from 170 to 750 µg and release of furanone from the coated catheter was about 15 µg for 30 days. The effect of DMHF-coated catheters on NCAC biofilm formation was observed by the scanning electron microscopy which revealed the absence of NCAC adherence on DMHF-coated catheters.<br><br>DISCUSSION: This study provides a design to develop furanone-coated biomaterials which could be implemented in healthcare settings to reduce medical device-associated infections. The excellent biological performance, combined with their antimicrobial properties, suggests that 2,5-dimethyl-4-hydroxy-3(2H)-furanone could be an effective anti-infective coating for implantable devices.},
}
@article {pmid31185817,
year = {2019},
author = {Dzianach, PA and Dykes, GA and Strachan, NJC and Forbes, KJ and Pérez-Reche, FJ},
title = {Challenges of biofilm control and utilization: lessons from mathematical modelling.},
journal = {Journal of the Royal Society, Interface},
volume = {16},
number = {155},
pages = {20190042},
doi = {10.1098/rsif.2019.0042},
pmid = {31185817},
issn = {1742-5662},
abstract = {This article reviews modern applications of mathematical descriptions of biofilm formation. The focus is on theoretically obtained results which have implications for areas including the medical sector, food industry and wastewater treatment. Examples are given as to how models have contributed to the overall knowledge on biofilms and how they are used to predict biofilm behaviour. We conclude that the use of mathematical models of biofilms has demonstrated over the years the ability to significantly contribute to the vast field of biofilm research. Among other things, they have been used to test various hypotheses on the nature of interspecies interactions, viability of biofilm treatment methods or forces behind observed biofilm pattern formations. Mathematical models can also play a key role in future biofilm research. Many models nowadays are analysed through computer simulations and continue to improve along with computational capabilities. We predict that models will keep on providing answers to important challenges involving biofilm formation. However, further strengthening of the ties between various disciplines is necessary to fully use the tools of collective knowledge in tackling the biofilm phenomenon.},
}
@article {pmid31185326,
year = {2019},
author = {Pourhajibagher, M and Ghorbanzadeh, R and Bahador, A},
title = {Antimicrobial properties of acrylic resins doped with Undaria pinnatifida exposed to light-emitting diode: In silico and in vitro assessments on multispecies biofilm-producing microbiota.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {27},
number = {},
pages = {210-215},
doi = {10.1016/j.pdpdt.2019.05.039},
pmid = {31185326},
issn = {1873-1597},
abstract = {BACKGROUND: This study sought to evaluates the efficiency of anti-microbial activity of acrylic resins doped with different concentrations of Undaria pinnatifida after activation with light-emitting diode (LED) at producing photodynamic damage to multispecies biofilm-producing microbiome.<br><br>MATERIAL AND METHODS: In this study, bioinformatics tools and computer simulation molecular modeling were used to evaluate the capacity of ferredoxin (FDX), an electron acceptor in metabolic pathways of U. pinnatifida, which can discharge electrons produced from photo-excited chlorophyll-a (Chl-a) by LED irradiation. Acrylic resin discs containing different concentration of U. pinnatifida (0, 0.5, 1, and 2%) were fabricated and were subjected to LED irradiation immediately before each experiment. After continuously rinsed (up to 30 days), the antimicrobial activity of acrylic resins doped with U. pinnatifida following photo-activation was determined by disc agar diffusion, biofilm formation inhibition, and eluted component assays versus bacterial species linked to caries that constitute a mixed biofilm including Streptococcus mutans, S. sanguinis, and Lactobacillus acidophilus, as well as Candida albicans as main etiology of candidal stomatitis.<br><br>RESULTS: Modeling and a virtual screening analysis of FDX indicated that it is a stable protein with an iron-sulfur center that can discharge electrons produced from photo-excited Chl-a and transfers them to FDX-NADP+ reductase for NADP+ reduction in photosystem I, which is essential in the Calvin cycle for carbon assimilation. FDX acts as an electron transfer agent in the redox reactions. The results showed that growth inhibition zones were not seen around acrylic resin discs in any group. In biofilm test, the colony counts of all test microorganisms significantly decreased (36%-87%) by an increase in the percentage of U. pinnatifida in acrylic resins after photo-activation (P < 0.05). Acrylic resins doped with 2% wt. U. pinnatifida following photo-activation using LED was inhibited biofilm formation by the test microorganisms, up to 30 days of rinsing.<br><br>CONCLUSION: Based on the results presented here, an acrylic resin containing U. pinnatifida, even at the lowest concentration, following photo-activation using LED have antimicrobial properties against planktonic and biofilm forms of the cariogenic microorganisms as well as C. albicans.},
}
@article {pmid31182496,
year = {2019},
author = {Nicastro, LK and Tursi, SA and Le, LS and Miller, AL and Efimov, A and Buttaro, B and Tam, V and Tükel, Ç},
title = {Cytotoxic Curli Intermediates Form during Salmonella Biofilm Development.},
journal = {Journal of bacteriology},
volume = {201},
number = {18},
pages = {},
doi = {10.1128/JB.00095-19},
pmid = {31182496},
issn = {1098-5530},
support = {P30 CA006927/CA/NCI NIH HHS/United States ; R21 AI126133/AI/NIAID NIH HHS/United States ; R21 AI132996/AI/NIAID NIH HHS/United States ; R56 AI125429/AI/NIAID NIH HHS/United States ; },
abstract = {Enterobacteriaceae produce amyloid proteins called curli that are the major proteinaceous component of biofilms. Amyloids are also produced by humans and are associated with diseases such as Alzheimer's. During the multistep process of amyloid formation, monomeric subunits form oligomers, protofibrils, and finally mature fibrils. Amyloid β oligomers are more cytotoxic to cells than the mature amyloid fibrils. Oligomeric intermediates of curli had not been previously detected. We determined that turbulence inhibited biofilm formation and that, intriguingly, curli aggregates purified from cultures grown under high-turbulence conditions were structurally smaller and contained less DNA than curli preparations from cultures grown with less turbulence. Using flow cytometry analysis, we demonstrated that CsgA was expressed in cultures exposed to higher turbulence but that these cultures had lower levels of cell death than less-turbulent cultures. Our data suggest that the DNA released during cell death drives the formation of larger fibrillar structures. Consistent with this idea, addition of exogenous genomic DNA increased the size of the curli intermediates and led to binding to thioflavin T at levels observed with mature aggregates. Similar to the intermediate oligomers of amyloid β, intermediate curli aggregates were more cytotoxic than the mature curli fibrils when incubated with bone marrow-derived macrophages. The discovery of cytotoxic curli intermediates will enable research into the roles of amyloid intermediates in the pathogenesis of Salmonella and other bacteria that cause enteric infections.IMPORTANCE Amyloid proteins are the major proteinaceous components of biofilms, which are associated with up to 65% of human bacterial infections. Amyloids produced by human cells are also associated with diseases such as Alzheimer's. The amyloid monomeric subunits self-associate to form oligomers, protofibrils, and finally mature fibrils. Amyloid β oligomers are more cytotoxic to cells than the mature amyloid fibrils. Here we detected oligomeric intermediates of curli for the first time. Like the oligomers of amyloid β, intermediate curli fibrils were more cytotoxic than the mature curli fibrillar aggregates when incubated with bone marrow-derived macrophages. The discovery of cytotoxic curli intermediates will enable research into the roles of amyloid intermediates in the pathogenesis of Salmonella and other bacteria that cause enteric infections.},
}
@article {pmid31181853,
year = {2019},
author = {Lotlikar, SR and Gallaway, E and Grant, T and Popis, S and Whited, M and Guragain, M and Rogers, R and Hamilton, S and Gerasimchuk, NG and Patrauchan, MA},
title = {Polymeric Composites with Silver (I) Cyanoximates Inhibit Biofilm Formation of Gram-Positive and Gram-Negative Bacteria.},
journal = {Polymers},
volume = {11},
number = {6},
pages = {},
doi = {10.3390/polym11061018},
pmid = {31181853},
issn = {2073-4360},
support = {1R15AI088594-01A1//National Institutes of Health/ ; CC 6598//Cottrell College Research Corporation/ ; },
abstract = {Biofilms are surface-associated microbial communities known for their increased resistance to antimicrobials and host factors. This resistance introduces a critical clinical challenge, particularly in cases associated with implants increasing the predisposition for bacterial infections. Preventing such infections requires the development of novel antimicrobials or compounds that enhance bactericidal effect of currently available antibiotics. We have synthesized and characterized twelve novel silver(I) cyanoximates designated as Ag(ACO), Ag(BCO), Ag(CCO), Ag(ECO), Ag(PiCO), Ag(PICO) (yellow and red polymorphs), Ag(BIHCO), Ag(BIMCO), Ag(BOCO), Ag(BTCO), Ag(MCO) and Ag(PiPCO). The compounds exhibit a remarkable resistance to high intensity visible light, UV radiation and heat and have poor solubility in water. All these compounds can be well incorporated into the light-curable acrylate polymeric composites that are currently used as dental fillers or adhesives of indwelling medical devices. A range of dry weight % from 0.5 to 5.0 of the compounds was tested in this study. To study the potential of these compounds in preventing planktonic and biofilm growth of bacteria, we selected two human pathogens (Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus) and Gram-positive environmental isolate Bacillus aryabhattai. Both planktonic and biofilm growth was abolished completely in the presence of 0.5% to 5% of the compounds. The most efficient inhibition was shown by Ag(PiCO), Ag(BIHCO) and Ag(BTCO). The inhibition of biofilm growth by Ag(PiCO)-yellow was confirmed by scanning electron microscopy (SEM). Application of Ag(BTCO) and Ag(PiCO)-red in combination with tobramycin, the antibiotic commonly used to treat P. aeruginosa infections, showed a significant synergistic effect. Finally, the inhibitory effect lasted for at least 120 h in P. aeruginosa and 36 h in S. aureus and B. aryabhattai. Overall, several silver(I) cyanoximates complexes efficiently prevent biofilm development of both Gram-negative and Gram-positive bacteria and present a particularly significant potential for applications against P. aeruginosa infections.},
}
@article {pmid31181494,
year = {2019},
author = {Yang, S and Guo, B and Shao, Y and Mohammed, A and Vincent, S and Ashbolt, NJ and Liu, Y},
title = {The value of floc and biofilm bacteria for anammox stability when treating ammonia-rich digester sludge thickening lagoon supernatant.},
journal = {Chemosphere},
volume = {233},
number = {},
pages = {472-481},
doi = {10.1016/j.chemosphere.2019.05.287},
pmid = {31181494},
issn = {1879-1298},
abstract = {Ammonia-rich lagoon supernatant was treated using anammox process in an integrated fixed-film activated sludge (IFAS) laboratory reactor. Effective anammox activities were demonstrated over 259 days of operation. The ammonium removal efficiency reached 94% in Phase I with influent concentrations of NH4+, NO2- and chemical oxygen demand (COD) at 250 mg-N/L, 325 mg-N/L, and 145 mg-COD/L, and reached 88% in Phase II at 420 mg-N/L, 525 mg-N/L, and 305 mg-COD/L. When supplemented with nitritation effluent for nitrite sources in Phase III, the influent COD concentration increased to 583 mg-COD/L without loss of ammonia removal efficiency (87%). The specific anammox activity was higher in biofilm than in the suspended flocs (P < 0.05), increased from Phase I to II (P < 0.05), and decreased in Phase III. Ammonia removal related genes were quantified using qPCR. Results showed higher anammox gene (AMX nirS) prevalence in biofilm, while denitrification genes (nosZ and narG) were higher in flocs (P < 0.05). Microbial community analysis showed that the seeded anammox bacteria Candidatus Brocadia was maintained at 19% in the biofilm and only 0.3% in the flocs. The major taxa in the flocs were related to denitrifiers. The floc community was affected largely under high COD conditions, but the biofilm community was not. These results suggest that the anammox activity in biofilm is resilient to high COD loadings, due to the existence of flocs with denitrification activity. The segregation of bacterial communities between biofilm and flocs in the anammox IFAS system resulted in high ammonia removal efficiency and resistance to high organic loadings.},
}
@article {pmid31180246,
year = {2019},
author = {Liu, J and Jiang, J and Zong, J and Li, B and Pan, T and Diao, Y and Zhang, Z and Zhang, X and Lu, M and Wang, S},
title = {Antibacterial and anti-biofilm effects of fatty acids extract of dried Lucilia sericata larvae against Staphylococcus aureus and Streptococcus pneumoniae in vitro.},
journal = {Natural product research},
volume = {},
number = {},
pages = {1-4},
doi = {10.1080/14786419.2019.1627353},
pmid = {31180246},
issn = {1478-6427},
abstract = {Development of new effective antimicrobial drugs is still a big challenge to date due to microbial infection remains an inevitable problem against human health. In this study, fatty acids extract of Lucilia sericata larvae (LFAs) was obtained and evaluated by gas chromatograph-mass spectrometry (GC-MS), and its antibacterial activity against Staphylococcus aureus (S. aureus) and Streptococcus pneumoniae (S. pneumoniae) was investigated. We found that LFAs exhibited effective antibacterial activity against S. aureus and S. pneumoniae with minimal inhibitory concentrations (MICs) of 125 μg/mL and 100 μg/mL, respectively. The bacterial wall and membrane were the main targets, which was confirmed by fluorescence microscopy, scanning electron microscopy and transmission electron microscopy. Furthermore, a notable anti-biofilm activity against S. aureus and S. pneumoniae was also observed, which was able to both prevent biofilm formation and eradicate mature biofilms of these bacteria. As a promising antibacterial agent, LFAs showed good application prospects in clinical practice.},
}
@article {pmid31180065,
year = {2019},
author = {Lahiri, D and Dash, S and Dutta, R and Nag, M},
title = {Elucidating the effect of anti-biofilm activity of bioactive compounds extracted from plants.},
journal = {Journal of biosciences},
volume = {44},
number = {2},
pages = {},
pmid = {31180065},
issn = {0973-7138},
}
@article {pmid31179649,
year = {2019},
author = {Liu, L and Ye, C and Soteyome, T and Zhao, X and Xia, J and Xu, W and Mao, Y and Peng, R and Chen, J and Xu, Z and Shirtliff, ME and Harro, JM},
title = {Inhibitory effects of two types of food additives on biofilm formation by foodborne pathogens.},
journal = {MicrobiologyOpen},
volume = {},
number = {},
pages = {e853},
doi = {10.1002/mbo3.853},
pmid = {31179649},
issn = {2045-8827},
support = {B17018//111 Project/ ; 31501582//National Natural Science Foundation of China/ ; 2018CFB514//Hubei Provincial Natural Science Foundation of China/ ; },
abstract = {The inhibition of microbial biofilms is a significant concern in food safety. In the present study, the inhibitory effect of sodium citrate and cinnamic aldehyde on biofilm formation at minimum inhibitory concentrations (MICs) and sub-MICs was investigated for Escherichia coli O157:H7 and Staphylococcus aureus. The biofilm inhibition rate was measured to evaluate the effect of sodium citrate on S. aureus biofilms at 24, 48, 72, and 96 hr. According to the results, an antibiofilm effect was shown by both food additives, with 10 mg/ml of sodium citrate exhibiting the greatest inhibition of S. aureus biofilms at 24 hr (inhibition rate as high as 77.51%). These findings strongly suggest that sodium citrate exhibits a pronounced inhibitory effect on biofilm formation with great potential in the extension of food preservation and storage.},
}
@article {pmid31177828,
year = {2019},
author = {Yunda, E and Quilès, F},
title = {In situ spectroscopic analysis of Lactobacillus rhamnosus GG flow on an abiotic surface reveals a role for nutrients in biofilm development.},
journal = {Biofouling},
volume = {35},
number = {5},
pages = {494-507},
doi = {10.1080/08927014.2019.1617279},
pmid = {31177828},
issn = {1029-2454},
abstract = {In this work, infrared spectroscopy was used to monitor the changes in the biochemical composition of biofilms of the probiotic bacterium Lactobacillus rhamnosus GG (LGG) in three nutritive media (10-fold diluted MRS, AOAC, and mTSB), in situ and under flow conditions. Epifluorescence microscopy was used to observe the shape of LGG cells and their distribution on the surface. Spectroscopic fingerprints recorded as a function of time revealed a medium-dependent content of nucleic acids, phospholipids and polysaccharides in the biofilms. In addition, time-dependent synthesis of lactic acid was observed in MRS/10 and AOAC/10. Polysaccharides were produced to the highest extent in mTSB/10, and the biofilms obtained were the densest in this medium. The rod shape of the cells was preserved in MRS/10, whereas acidic stress induced in AOAC/10 and the nutritional quality of mTSB/10 led to strong morphological changes. These alterations due to the nutritive environment are important to consider in research and use of LGG biofilms.},
}
@article {pmid31177008,
year = {2019},
author = {Pousti, M and Lefèvre, T and Amirdehi, MA and Greener, J},
title = {A surface spectroscopy study of a Pseudomonas fluorescens biofilm in the presence of an immobilized air bubble.},
journal = {Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy},
volume = {222},
number = {},
pages = {117163},
doi = {10.1016/j.saa.2019.117163},
pmid = {31177008},
issn = {1873-3557},
abstract = {A linear spectral mapping technique was applied to monitor the growth of biomolecular absorption bands at the bio-interface of a nascent Pseudomonas fluorescens biofilm during and after interaction with a surface-adhered air bubble. Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectra were obtained in different locations in a microchannel with adequate spatial and temporal resolution to study the effect of a static bubble on the evolution of protein and lipid signals at the ATR crystal surface. The results reveal that the presence of a bubble during the lag phase modified levels of extracellular lipids and affected a surface restructuring process, many hours after the bubble's disappearance.},
}
@article {pmid31174686,
year = {2019},
author = {Shah, MS and Qureshi, S and Kashoo, Z and Farooq, S and Wani, SA and Hussain, MI and Banday, MS and Khan, AA and Gull, B and Habib, A and Khan, SM and Dar, BA},
title = {Methicillin resistance genes and in vitro biofilm formation among Staphylococcus aureus isolates from bovine mastitis in India.},
journal = {Comparative immunology, microbiology and infectious diseases},
volume = {64},
number = {},
pages = {117-124},
doi = {10.1016/j.cimid.2019.02.009},
pmid = {31174686},
issn = {1878-1667},
abstract = {INTRODUCTION: Biofilms, an assemblage of microbial cells irreversibly associated with a surface and enclosed in a matrix of polysaccharide material pose serious health challenges, resulting in high economic losses. The emergence of methicillin-resistant S. aureus (MRSA) infections and ability to form biofilms in dairy animals is of emerging concern for livestock and public health owing to their association with serious infections. The present study was undertaken to examine the presence of methicillin resistance genes among the biofilm forming Staphylococcus aureus strains isolated from cases of acute and subacute bovine mastitis. A total of 150 mastitic milk samples referred to Veterinary Clinical Complex, Shuhama (Aulesteng) SKUAST-K were screened in present study. The methicillin resistant Staphylococcus aureus isolates were also screened for in vitro biofilm forming ability.<br><br>RESULTS: A total of 80 (53.33%) S. aureus isolates were recovered from cases of bovine mastitis of which 20 (25%) were methicillin (mecA) gene positive. Of the 20 mecA positive isolates, 20% were positive for SCCmec I, 35% for SCCmec IV and 45% for SCCmec V subtypes. In vitro antibiotic sensitivity testing of MRSA revealed complete resistance towards methicillin and other pencillin group of antibiotics.<br><br>CONCLUSION: A significant correlation was observed between in vitro biofilm formation and presence of methicillin resistance gene in S aureus isolates recovered from acute and subacute mastitis. The Staphylococcus aureus isolates positive for methicillin resistance gene (mecA) were either strong or moderate biofilm formers.},
}
@article {pmid31173863,
year = {2019},
author = {Rajasekharan, SK and Lee, JH and Lee, J},
title = {Aripiprazole repurposed as an inhibitor of biofilm formation, and sterol biosynthesis in multi-drug resistant Candida albicans.},
journal = {International journal of antimicrobial agents},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ijantimicag.2019.05.016},
pmid = {31173863},
issn = {1872-7913},
abstract = {Drug repurposing is an anticipative chemotherapeutic strategy that serves to accentuate the inadequacy of antifungal drugs. The study identifies an antipsychotic drug, aripiprazole, as a biofilm and hyphal inhibitor of Candida albicans. Microtitre plate biofilm inhibition, metabolic activity, and hyphal inhibitory assays were used initially to assess the potency of aripiprazole, while assays like filipin staining, reactive oxygen species staining, cAMP rescue, propidium iodide staining, computational studies, and qRT-PCR assays were used to elucidate its mode of action. The study revealed aripiprazole functioned in a manner similar to standard azoles, especially the imidazole ketoconazole, by inhibiting pseudohyphal formations during the early stages of hyphal development. The action of aripiprazole on C. albicans was dose-dependent and it exhibited varied action mechanisms at low and high dosages. At low dosage, aripiprazole outperformed ketoconazole in terms of inhibiting biofilm formation, hyphal filamentations, and yeast flocculation whereas at higher dosage it mimicked ketoconazole. In conclusion, the study illustrates the anti-candidal potential and mechanistic activities of aripiprazole, and suggests the future use of this drug as an anti-biofilm agent.},
}
@article {pmid31173560,
year = {2019},
author = {Kreth, J and Ferracane, JL and Pfeifer, CS and Khajotia, S and Merritt, J},
title = {At the Interface of Materials and Microbiology: A Call for the Development of Standardized Approaches to Assay Biomaterial-Biofilm Interactions.},
journal = {Journal of dental research},
volume = {98},
number = {8},
pages = {850-852},
doi = {10.1177/0022034519854685},
pmid = {31173560},
issn = {1544-0591},
support = {K02 DE025280/DE/NIDCR NIH HHS/United States ; R01 DE026113/DE/NIDCR NIH HHS/United States ; U01 DE023756/DE/NIDCR NIH HHS/United States ; R56 DE021726/DE/NIDCR NIH HHS/United States ; R35 DE028252/DE/NIDCR NIH HHS/United States ; R15 DE019940/DE/NIDCR NIH HHS/United States ; },
}
@article {pmid31172798,
year = {2019},
author = {Dell'Olmo, E and Gaglione, R and Pane, K and Sorbo, S and Basile, A and Esposito, S and Arciello, A},
title = {Fighting multidrug resistance with a fruit extract: anti-cancer and anti-biofilm activities of Acca sellowiana.},
journal = {Natural product research},
volume = {},
number = {},
pages = {1-4},
doi = {10.1080/14786419.2019.1624961},
pmid = {31172798},
issn = {1478-6427},
abstract = {In this study, the efficacy of Acca sellowiana fruit acetonic extract on human MDR cancer cells was tested for the first time, and it was demonstrated that the fruit extract is effective on both sensitive and resistant tumor cells. The effects of A. sellowiana extract on bacterial biofilm were also examined for the first time. By crystal violet assays and confocal microscopy analyses, it was demonstrated that the plant extract is able to strongly inhibit biofilm formation of both sensitive and resistant bacterial strains. Furthermore, antimicrobial activity assays and TEM analyses clearly demonstrated the effectiveness of plant extract on planktonic bacterial cells in both sensitive and resistant strains. Altogether, these findings intriguingly expand the panel of activities of A. sellowiana fruit extract with respect to previous reports, and open interesting perspectives to its therapeutic applications.},
}
@article {pmid31171741,
year = {2019},
author = {Shakibaie, M and Hajighasemi, E and Adeli-Sardou, M and Doostmohammadi, M and Forootanfar, H},
title = {Antimicrobial and anti-biofilm activities of Bi subnitrate and BiNPs produced by Delftia sp. SFG against clinical isolates of Staphylococcus aureus, Pseudomonas aeruginosa, and Proteus mirabilis.},
journal = {IET nanobiotechnology},
volume = {13},
number = {4},
pages = {377-381},
doi = {10.1049/iet-nbt.2018.5102},
pmid = {31171741},
issn = {1751-875X},
abstract = {In the present study Delftia sp. Shakibaie, Forootanfar, and Ghazanfari (SFG), was applied for preparation of biogenic Bi nanoparticles (BiNPs) and antibacterial and anti-biofilm activities of the purified BiNPs were investigated by microdilution and disc diffusion methods. Transmission electron micrographs showed that the produced nanostructures were spherical with a size range of 40-120 nm. The measured minimum inhibitory concentration of both the Bi subnitrate and BiNPs against three biofilms producing bacterial pathogens of Staphylococcus aureus, Pseudomonas aeruginosa, and Proteus mirabilis were found to be above 1280 µg/ml. Addition of BiNPs (1000 µg/disc) to antibiotic discs containing tobramycin, nalidixic acid, ceftriaxone, bacitracin, cefalexin, amoxicillin, and cefixime significantly increased the antibacterial effects against methicillin-resistant S. aureus (MRSA) in comparison with Bi subnitrate (p < 0.05). Furthermore, the biogenic BiNPs decreased the biofilm formation of S. aureus, P. aeruginosa, and P. mirabilis to 55, 85, and 15%, respectively. In comparison to Bi subnitrate, BiNPs indicated significant anti-biofilm activity against P. aeruginosa (p < 0.05) while the anti-biofilm activity of BiNPs against S. aureus and P. mirabilis was similar to that of Bi subnitrate. To sum up, the attained results showed that combination of biogenic BiNPs with commonly used antibiotics relatively enhanced their antibacterial effects against MRSA.},
}
@article {pmid31170510,
year = {2019},
author = {Kłodzińska, SN and Pletzer, D and Rahanjam, N and Rades, T and Hancock, REW and Nielsen, HM},
title = {Hyaluronic acid-based nanogels improve in vivo compatibility of the anti-biofilm peptide DJK-5.},
journal = {Nanomedicine : nanotechnology, biology, and medicine},
volume = {20},
number = {},
pages = {102022},
doi = {10.1016/j.nano.2019.102022},
pmid = {31170510},
issn = {1549-9642},
abstract = {Anti-biofilm peptides are a subset of antimicrobial peptides and represent promising broad-spectrum agents for the treatment of bacterial biofilms, though some display host toxicity in vivo. Here we evaluated nanogels composed of modified hyaluronic acid for the encapsulation of the anti-biofilm peptide DJK-5 in vivo. Nanogels of 174 to 194 nm encapsulating 33-60% of peptide were created. Efficacy and toxicity of the nanogels were tested in vivo employing a murine abscess model of a Pseudomonas aeruginosa LESB58 high bacterial density infection. The dose of DJK-5 that could be administered intravenously to mice without inducing toxicity was more than doubled after encapsulation in nanogels. Upon subcutaneous administration, the toxicity of the DJK-5 in nanogels was decreased four-fold compared to non-formulated peptide, without compromising the anti-abscess effect of DJK-5. These findings support the use of nanogels to increase the safety of antimicrobial and anti-biofilm peptides after intravenous and subcutaneous administration.},
}
@article {pmid31169511,
year = {2019},
author = {Mendoza, MV and Sáez, RT},
title = {Modelling biofilm anaerobic reactor with effluent from hydrolytic/acidogenic reactor as substrate.},
journal = {Water science and technology : a journal of the International Association on Water Pollution Research},
volume = {79},
number = {8},
pages = {1534-1540},
doi = {10.2166/wst.2019.152},
pmid = {31169511},
issn = {0273-1223},
mesh = {Anaerobiosis ; Bacteria ; *Biofilms ; Bioreactors/*statistics &amp; numerical data ; Hydrolysis ; Methane ; *Models, Statistical ; Waste Disposal, Fluid/*statistics &amp; numerical data ; },
abstract = {This work presents modelling of an anaerobic biofilm reactor using ceramic bricks as support. The results were compared with the experimental data. It was observed that the substrate concentration curves showed the same tendency. The methane formation curves showed significant differences. The substrate removal efficiency was 83%. In the steady state, the experimental data were higher than the model, from the result the substrate degrading bacteria grew enough to reach biofilm and that the effect of the shear stress was more significant as the biofilm increased in thickness. To the methane production, the model in steady state reached a maximum value of 0.56 m3 CH4/m3 *d and the experimental data reached 0.42 (m3 CH4/m3 * d). The biofilm thickness calculated by the model was 14 μm.},
}
@article {pmid31169162,
year = {2019},
author = {Kriswandini, IL and Rahardjo, MB and Budi, HS and Amalia, R},
title = {The difference in biofilm molecular weight in Streptococcus mutans and Aggregatibacter actinomycetemcomitans induced by sucrose and soy protein (glycine soja).},
journal = {Indian journal of dental research : official publication of Indian Society for Dental Research},
volume = {30},
number = {2},
pages = {273-276},
doi = {10.4103/ijdr.IJDR_183_17},
pmid = {31169162},
issn = {1998-3603},
abstract = {Context: Biofilms consist of microbial cells and extracellular polymeric substance (EPS). Streptococcus mutans and Aggregatibacter actinomycetemcomtans are bacteria that can form biofilms and generate EPS. Biofilm formation can be induced by specific substances such as sucrose and protein.<br><br>Aims: To identify the molecular weight that determines biofilm protein profile expression of S. mutans and A. actinomycetemcomitans induced by sucrose (carbohydrate) and soy protein (glycine soja).<br><br>Settings and Design: Experimental laboratory study.<br><br>Materials and Methods: Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to determine the molecular weight.<br><br>Statistical Analysis Used: Nil.<br><br>Results: The results of analysis of protein SDS-PAGE showed the presence of 28 protein bands on A. actinomycetemcomitans biofilm in the media trypticase soy broth (TSB), 20 protein bands on biofilms of S. mutans in the media TSB, 29 protein bands on biofilm A. actinomycetemcomitans in the media brain heart infusion (BHI) + sucrose 2%, and 13 protein bands on biofilms of S. mutans in the media BHI + sucrose 2%.<br><br>Conclusion: There are differences in biofilm protein profile expression that determine the molecular weight of S. mutans biofilm and A. actinomycetemcomitans induced by sucrose (carbohydrate) and soy protein (glycine soja).},
}
@article {pmid31167793,
year = {2019},
author = {Le Mauff, F and Bamford, NC and Alnabelseya, N and Zhang, Y and Baker, P and Robinson, H and Codée, JDC and Howell, PL and Sheppard, DC},
title = {Molecular mechanism of Aspergillus fumigatus biofilm disruption by fungal and bacterial glycoside hydrolases.},
journal = {The Journal of biological chemistry},
volume = {294},
number = {28},
pages = {10760-10772},
doi = {10.1074/jbc.RA119.008511},
pmid = {31167793},
issn = {1083-351X},
support = {P41 GM103473/GM/NIGMS NIH HHS/United States ; P41 RR012408/RR/NCRR NIH HHS/United States ; },
abstract = {During infection, the fungal pathogen Aspergillus fumigatus forms biofilms that enhance its resistance to antimicrobials and host defenses. An integral component of the biofilm matrix is galactosaminogalactan (GAG), a cationic polymer of α-1,4-linked galactose and partially deacetylated N-acetylgalactosamine (GalNAc). Recent studies have shown that recombinant hydrolase domains from Sph3, an A. fumigatus glycoside hydrolase involved in GAG synthesis, and PelA, a multifunctional protein from Pseudomonas aeruginosa involved in Pel polysaccharide biosynthesis, can degrade GAG, disrupt A. fumigatus biofilms, and attenuate fungal virulence in a mouse model of invasive aspergillosis. The molecular mechanisms by which these enzymes disrupt biofilms have not been defined. We hypothesized that the hydrolase domains of Sph3 and PelA (Sph3h and PelAh, respectively) share structural and functional similarities given their ability to degrade GAG and disrupt A. fumigatus biofilms. MALDI-TOF enzymatic fingerprinting and NMR experiments revealed that both proteins are retaining endo-α-1,4-N-acetylgalactosaminidases with a minimal substrate size of seven residues. The crystal structure of PelAh was solved to 1.54 Å and structure alignment to Sph3h revealed that the enzymes share similar catalytic site residues. However, differences in the substrate-binding clefts result in distinct enzyme-substrate interactions. PelAh hydrolyzed partially deacetylated substrates better than Sph3h, a finding that agrees well with PelAh's highly electronegative binding cleft versus the neutral surface present in Sph3h Our insight into PelAh's structure and function necessitate the creation of a new glycoside hydrolase family, GH166, whose structural and mechanistic features, along with those of GH135 (Sph3), are reported here.},
}
@article {pmid31166981,
year = {2019},
author = {Pinto, M and Langer, TM and Hüffer, T and Hofmann, T and Herndl, GJ},
title = {The composition of bacterial communities associated with plastic biofilms differs between different polymers and stages of biofilm succession.},
journal = {PloS one},
volume = {14},
number = {6},
pages = {e0217165},
doi = {10.1371/journal.pone.0217165},
pmid = {31166981},
issn = {1932-6203},
abstract = {Once in the ocean, plastics are rapidly colonized by complex microbial communities. Factors affecting the development and composition of these communities are still poorly understood. Additionally, whether there are plastic-type specific communities developing on different plastics remains enigmatic. We determined the development and succession of bacterial communities on different plastics under ambient and dim light conditions in the coastal Northern Adriatic over the course of two months using scanning electron microscopy and 16S rRNA gene analyses. Plastics used were low- and high-density polyethylene (LDPE and HDPE, respectively), polypropylene (PP) and polyvinyl chloride with two typical additives (PVC DEHP and PVC DINP). The bacterial communities developing on the plastics clustered in two groups; one group was found on PVC and the other group on all the other plastics and on glass, which was used as an inert control. Specific bacterial taxa were found on specific surfaces in essentially all stages of biofilm development and in both ambient and dim light conditions. Differences in bacterial community composition between the different plastics and light exposures were stronger after an incubation period of one week than at the later stages of the incubation. Under both ambient and dim light conditions, one part of the bacterial community was common on all plastic types, especially in later stages of the biofilm development, with families such as Flavobacteriaceae, Rhodobacteraceae, Planctomycetaceae and Phyllobacteriaceae presenting relatively high relative abundances on all surfaces. Another part of the bacterial community was plastic-type specific. The plastic-type specific fraction was variable among the