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Bibliography on: Biofilm

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Robert J. Robbins is a biologist, an educator, a science administrator, a publisher, an information technologist, and an IT leader and manager who specializes in advancing biomedical knowledge and supporting education through the application of information technology. More About:  RJR | OUR TEAM | OUR SERVICES | THIS WEBSITE

RJR: Recommended Bibliography 02 Jul 2025 at 01:40 Created: 

Biofilm

Wikipedia: Biofilm A biofilm is any group of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular polymeric substances (EPS). The EPS components are produced by the cells within the biofilm and are typically a polymeric conglomeration of extracellular DNA, proteins, and polysaccharides. Because they have three-dimensional structure and represent a community lifestyle for microorganisms, biofilms are frequently described metaphorically as cities for microbes. Biofilms may form on living or non-living surfaces and can be prevalent in natural, industrial and hospital settings. The microbial cells growing in a biofilm are physiologically distinct from planktonic cells of the same organism, which, by contrast, are single-cells that may float or swim in a liquid medium. Biofilms can be present on the teeth of most animals as dental plaque, where they may cause tooth decay and gum disease. Microbes form a biofilm in response to many factors, which may include cellular recognition of specific or non-specific attachment sites on a surface, nutritional cues, or in some cases, by exposure of planktonic cells to sub-inhibitory concentrations of antibiotics. When a cell switches to the biofilm mode of growth, it undergoes a phenotypic shift in behavior in which large suites of genes are differentially regulated.

Created with PubMed® Query: ( biofilm[title] NOT 28392838[PMID] NOT 31293528[PMID] NOT 29372251[PMID] ) NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

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RevDate: 2025-06-28

Tran PN, Michalczyk AA, Catubig RA, et al (2025)

Corrosion of AISI 1030 mild steel is influenced by bacteria type, oxygen availability and biofilm formation under controlled laboratory conditions.

Journal of applied microbiology pii:8172001 [Epub ahead of print].

AIM: Bacteria are reported to have both stimulatory and inhibitory effects on the corrosion of metal. To investigate this, we measured corrosion of AISI 1030 mild steel by four species of bacteria: P. aeruginosa, Lelliottia WAP21, B. subtilis and E. cloacae in cultures with normal and restricted access to O2.

METHODS AND RESULTS: Scanning electron microscopy, three-dimensional profilometry and inductively coupled plasma-mass spectrometry were used to measure corrosion. Under aerobic conditions, all four bacterial strains protected the metal surface from pit formation compared with abiotic cultures, most likely through the formation of a biofilm that restricting oxygen access. In contrast, in low-oxygen environments, bacteria caused greater surface corrosion and biofilm formation. Specifically, Lelliottia WAP21 caused corrosion pits more than ten times deeper than those in abiotic cultures and 18-fold more Fe release relative to abiotic controls. Biofilm structures varied with oxygen availability, with each bacterial strain producing distinct biofilms with different elemental composition compared with the abiotic corrosion products. The O2 utilisation in the presence of metal may be related to bacterial metabolic activities including biofilm formation. The presence of Fe was metabolically favourable for bacteria and stimulated growth particularly in low O2 conditions.

CONCLUSION: Our findings show species-specific effects of bacteria on corrosion, where bacterial activity can either enhance or inhibit corrosion depending on oxygen availability.

RevDate: 2025-06-28

Xiong S, Zhang N, Sun H, et al (2025)

LtrA is critical for biofilm formation and colonization of Vibrio parahaemolyticus on food-related surfaces.

International journal of food microbiology, 441:111327 pii:S0168-1605(25)00272-7 [Epub ahead of print].

Vibrio parahaemolyticus is the leading causative agent of seafood-associated acute gastroenteritis. The formation of biofilms is one of the key reasons for its resistance to adverse environments and its persistence in seafood. Investigating the regulatory mechanisms of biofilm formation is beneficial for the development of new intervention methods to reduce V. parahaemolyticus contamination during seafood processing and storage. In this study, we identified a global regulator, LtrA (VPA0519), which is involved in regulating biofilm formation in V. parahaemolyticus. The deletion of ltrA led to a significant alteration in the transcription levels of 706 genes, including those associated with type III and VI secretion systems and biofilm formation. LtrA positively regulated biofilm formation by enhancing the production of exopolysaccharides, extracellular proteins, extracellular DNA, and cyclic di-GMP (c-di-GMP), as well as by decreasing swimming and swarming motility. The deletion of the ltrA gene also led to a reduction in the metabolic activity of biofilm cells but did not affect the production of capsular polysaccharide. Furthermore, the deletion of the ltrA gene resulted in a decrease in the biofilm formation ability of V. parahaemolyticus on the surfaces of shrimp (Parapenaeopsis hardwickii), crab (Portunus trituberculatus), polypropylene plastic, glass, and stainless steel. The findings in this study extend our understanding of the roles of LtrA and the genetic determinants involved in biofilm formation by V. parahaemolyticus.

RevDate: 2025-06-27

Shao S, Liu J, Pan D, et al (2025)

New insight on nitrogen and phosphorus removal of moving bed biofilm reactor driven by ferromanganese binary oxide: Performances and mechanisms.

Bioresource technology pii:S0960-8524(25)00857-0 [Epub ahead of print].

The moving bed biofilm reactor with different iron-manganese ratios was developed to treat the simulated domestic wastewater with a low carbon-to-nitrogen ratio. The result showed that NH4[+]-N and NO3[-]-N of 96 ± 2 % and 55 ± 5 %, 97 ± 1 % and 34 ± 6 %, and 40 ± 5 % and 75 ± 4 % were removed in phases II-IV, and phosphorus removal included adsorption of biological iron and manganese oxides and biological removal. Ferromanganese binary oxide stimulated the extracellular polymeric substances secretion, and dissolved organic matter accelerated the iron-manganese redox cycling. Furthermore, fate of manganese and iron was explored, indicating that location of iron-manganese redox cycling was mainly outside the cells. Specific mechanism of iron-manganese redox cycling driven nitrogen and phosphorus removal was clarified including biofilm community. In conclusion, iron-manganese redox cycling reduced the reactive oxygen species level, and Proteobacteria and Planctomycetota were the dominant genera for nutrient, Fe(II), and Mn(II) removal. This study provides a novel method for efficient removal of nutrients.

RevDate: 2025-06-27

Copeland R, P Yunker (2025)

Biofilm vertical growth dynamics are captured by an active fluid framework.

Physical biology [Epub ahead of print].

Bacterial biofilms, surface-attached microbial communities, grow horizontally across surfaces and vertically above them. Although a simple heuristic model for vertical growth was experimentally shown to accurately describe the behavior of diverse microbial species, the biophysical implications and theoretical basis for this empirical model were unclear. Here, we demonstrate that this heuristic model emerges naturally from fundamental principles of active fluid dynamics. By analytically deriving solutions for an active fluid model of vertical biofilm growth, we show that the governing equations reduce to the same form as the empirical model in both early- and late-stage growth regimes. Our analysis reveals that cell death and decay rates likely play key roles in determining the characteristic parameters of vertical growth. The active fluid model produces a single, simple equation governing growth at all heights that is surprisingly simpler than the heuristic model. With this theoretical basis, we explain why the vertical growth rate reaches a maximum at a height greater than the previously identified characteristic length scale. These results provide a theoretical foundation for a simple mathematical model of vertical growth, enabling deeper understanding of how biological and biophysical factors interact during biofilm development.

RevDate: 2025-06-27

Xia Z, Ng HY, Hu J, et al (2025)

Enhanced sulfamethoxazole removal by co-substrate supplementation in membrane-aerated biofilm photoreactor treating mariculture wastewater: multi-omics insights into performance, microbial mechanisms and antibiotic resistance genes.

Water research, 285:124073 pii:S0043-1354(25)00981-9 [Epub ahead of print].

The widespread overuse of antibiotics in mariculture poses significant environmental and health risks. Membrane-aerated biofilm photoreactor (MABPR), leveraging membrane aeration and microalgal-bacterial functionality, has demonstrated potential for nitrogen and antibiotic removal from wastewater. However, its application for antibiotic risk control under the high salinity and low organic strength typical of mariculture effluents remains largely unexplored. Co-metabolism, facilitated by co-substrate addition, has emerged as a promising strategy for enhancing antibiotic mitigation under environmental stresses. Yet, its effectiveness and underlying mechanisms in MABPR are not well understood. This study evaluated the effectiveness of external co-substrate (sodium acetate) supplementation for sulfamethoxazole (SMX) removal and control of antibiotic resistance genes (ARGs) in MABPR treating mariculture effluents. Results demonstrated that MABPR could achieve considerable SMX removal from mariculture wastewater. Concurrently, the addition of co-substrate developed an active "energy conservation-metabolic enzyme machinery" in MABPR, significantly upregulating the expression of metabolic enzymes and energy conservation pathways (up to 8.25-fold upregulation than control), with microalgae as the primary contributors, thereby fostering metabolic functions and activities. This enhancement significantly improved SMX removal efficiencies by 41.1 %-80.6 %, while also enhancing system resilience even under high SMX loading. Concurrently, co-substrate supplementation alleviated oxidative stress, reducing intracellular reactive oxygen species (ROS) levels by approximately 14 %. Total ARG abundance decreased by 14.2-20.4 % under the co-substrate-amended condition. Transcriptomic analysis revealed that co-substrate addition significantly upregulated antioxidant defense systems while suppressing gene expression involved in the SOS response and conjugative transfer. These transcriptomic changes showed significant correlation with the ARG abundance reductions, suggesting that co-substrate supplementation likely restricts ARG dissemination by modulating cellular stress responses. Our findings not only highlight the potential of external co-substrate supplementation for antibiotic risk mitigation during mariculture wastewater treatment, but also provide unique insights into the co-substrate-mediated underlying regulatory mechanisms for antibiotic risk control in MABPR.

RevDate: 2025-06-28

Almutairy B (2025)

Flavonoid-mediated biofilm inhibition and toxicological evaluation of Atriplex laciniata against multidrug-resistant MRSA.

Frontiers in pharmacology, 16:1577052.

Multidrug-resistant (MDR) superbugs threaten the efficacy of antibiotics, so new drug formulations from synthetic or natural sources are needed to combat antimicrobial-resistant (AMR) infections. Traditional herbs are often considered alternatives for treating AMR and MDR infections. The present study involves evaluations of the efficacy and safety of Atriplex laciniata aqueous (AL-Aq-Ext) and flavonoid-rich (AL-Flv-Ext) extracts against MDR MRSA strains. The efficacies of the extracts against MRSA were tested for bacterial viability and biofilm inhibition through the MTT assay, OD600 nm measurements, confocal laser scanning microscopy (CLSM) for morphological observations, and amyloid-staining Congo-red phenotypic method. The safety of each extract was evaluated through comprehensive toxicological assessments, including acute toxicity, tissue biocompatibility, vital organ toxicity, and relative hemolysis. The results indicate MRSA cell viability at minimum inhibitory concentrations (MICs) of 512 μg/mL for AL-Aq-Ext and 256 μg/mL for AL-Flv-Ext. At these MICs, the extracts also exhibited bactericidal effects with zones of inhibition of 22 mm for AL-Aq-Ext and 20 mm for AL-Flv-Ext, which are comparable to the 25 mm for vancomycin. Both extracts showed more than 90% biofilm inhibition, which were confirmed through OD600 nm measurements, morphological detection based on reduction in fluorescence intensities via CLSM, and phenotype by the Congo-red amyloid-staining assay. The time-kill kinetics assays indicated prolonged bactericidal effects lasting approximately 73 h against MRSA. In terms of safety, acute toxicity studies were conducted by administering MIC doses of AL-Aq-Ext and AL-Flv-Ext orally to mice over 10 d, which revealed 100% survival rates and no immediate adverse effects. Histopathological analysis of the vital organs (liver and kidneys) showed no tissue damage, confirming the absence of acute organ toxicity; hemolysis assays demonstrated no red blood cell lysis at any tested concentration, indicating excellent blood compatibility. These findings demonstrate that A. laciniata extracts (AL-Aq-Ext and AL-Flv-Ext) are rich in flavonoids, safe, biocompatible, and suitable for further pharmacological development, with promising potential for preclinical and clinical trials. However, the present study is limited to acute toxicity and short-term exposure evaluations; hence, future research should focus on identifying specific bioactive compounds, evaluating the long-term toxicities, studying the pharmacokinetics, assessing the efficacies in disease models, and investigating potential immunogenicity and drug interactions to fully establish the therapeutic potential of the extracts.

RevDate: 2025-06-29

Behshood P, E Tajbakhsh (2025)

Systematic review and meta-analysis of the association between biofilm formation and antibiotic resistance in MRSE Isolated from Iranian patients.

Caspian journal of internal medicine, 16(2):225-232.

BACKGROUND: Biofilms are organized communities of microorganisms encased in a self-produced matrix that adheres to surfaces and can have both beneficial and detrimental effects in various environments. These biofilms have been linked to severe infections in humans. We investigated the association between antibiotic resistance and biofilm formation in methicillin-resistant Staphylococcus epidermidis (MRSE) isolates.

METHODS: A comprehensive search was conducted through data medical data bases using a combination of mesh terms. The data were analyzed using STATA meta-analysis software, and a random effects model was employed to determine the pooled prevalence with a 95% confidence interval (CI).

RESULTS: Our findings revealed that the prevalence of MRSA was 61.75% (95% CI: 35.6-99.1). The cumulative rate of biofilm formation in MRSE strains was reported to be 83.4% (95% CI: 47.8-99.4). Among the biofilm-related genes, the SdrG gene exhibited the highest frequency (98%), followed by the atlG gene with a frequency of 84%.

CONCLUSION: Out of the seven, three documented a positive association. Given the propensity of MRSE strains to form biofilms, it is crucial to implement preventive measures against infections caused by these strains.

RevDate: 2025-06-28

Shinde RA, Adole VA, Patil RH, et al (2025)

Harnessing thiazole chemistry for antifungal strategies through an experimental and computational chemistry approach: anti-biofilm, molecular docking, dynamics, and DFT analysis.

RSC advances, 15(27):21838-21858.

This study reports the design, synthesis, and evaluation of four novel (E)-2-(2-(1-(5-chlorothiophen-2-yl)ethylidene)hydrazineyl)-4-(aryl)thiazole derivatives (4a-4d) as potential anti-biofilm agents against Candida albicans. The compounds were structurally characterized by FT-IR, [1]H NMR, [13]C NMR, and HRMS spectral techniques. Biofilm inhibition assays revealed that derivatives 4a-4c suppressed over 50% of biofilm formation at a concentration of 12.5 μg mL[-1], although exopolysaccharide production remained largely unaffected. Molecular docking indicated strong binding affinities toward lanosterol 14α-demethylase, with 4a achieving the highest docking score (-8.715 kcal mol[-1]) through hydrogen bonding and π-π stacking interactions. Stability of the 4c-protein complex was confirmed by molecular dynamics simulations, supported by RMSD and flexibility analyses. An in-depth computational analysis was also performed on the most active thiazole derivative, compound 4c. DFT and NBO analyses of 4c indicated favourable geometry and key electron delocalization, while ELF, LOL, NCI, and RDG studies highlighted the role of non-covalent interactions in stabilizing the molecular framework. Additionally, the ADME profile of 4c demonstrated favourable pharmacokinetic properties, including high gastrointestinal absorption and a moderate lipophilicity index, highlighting its potential as a lead antifungal scaffold.

RevDate: 2025-06-26

Zhang X, Niu Z, Chen M, et al (2025)

Characterization of phthalate esters (PAEs) in urban water supply system: PAE-degrading bacteria existed in the pipeline biofilm.

Water research, 285:124055 pii:S0043-1354(25)00963-7 [Epub ahead of print].

The water supply system is a crucial infrastructure related to the people's livelihood. To enhance the performance of pipelines, additives are commonly added to the plastic pipes. Among these, phthalate esters (PAEs), a type of emerging contaminants, have been proven to be released from plastic pipes to water. In this study, we investigated the occurrence of PAEs in drinking water supply systems, isolated PAE-degrading bacteria and explored their characteristics. Firstly, a total of six PAEs were detected throughout the process from raw water to tap water, and the concentrations of Σ6PAEs in tap water at three sampling sites were all higher than those in the finished water. Secondly, using PAEs as the sole carbon source, four strains of PAE-degrading bacteria were isolated from the simulated pipeline biofilm. Within 12 h, the degradation rates of these four strains towards Σ4PAEs (initial concentration: 1 mg/L) were 34.83 % - 56.54 %. Thirdly, considering the presence of multiple carbon sources, residual chlorine, and other bacteria, the behavior of the isolated PAE-degrading bacteria in the actual pipeline environment was examined. It showed that PAE-degrading bacteria preferentially used other carbon sources in tap water rather than PAEs, and the residual chlorine inhibited the bacteria's ability to degrade PAEs. Moreover, despite the presence of other bacteria from the biofilm, the PAE-degrading bacteria still became the dominant bacteria. Consequently, this study demonstrated the feasibility of PAE degradation by bacteria isolated from the pipeline biofilm, which was helpful for understanding the biochemical degradation process of PAEs in drinking water supply systems.

RevDate: 2025-06-26

Li N, Liu Y, Wan H, et al (2025)

Nature-inspired water purification: Integrating riverbank filtration and biofilm-regulating nanofiltration.

Water research, 285:124077 pii:S0043-1354(25)00985-6 [Epub ahead of print].

Nanofiltration (NF) is an effective method for removing various emerging pollutants in drinking water. However, its conventional application, primarily adapted from desalination practices, faces challenges such as stringent pretreatment requirements, high energy consumption, and severe membrane fouling. To address these issues, we modified the NF process by transitioning from the traditional spiral-wound configuration to a submerged flat-sheet configuration and incorporating riverbank filtration (RBF) as a pretreatment. Experimental results demonstrated that the RBF-NF system could selectively remove natural organic matter (60.6 %) and various trace organic compounds (30.7 %-68.0 %), without the losses of beneficial ions. Additionally, the RBF-NF system reduced the risk of microbial regrowth in treated water by effectively lowering assimilable organic carbon and phosphorus levels, with removal of 52.1 % and 35.0 %, respectively. More importantly, a membrane biofilm naturally developed on the NF membrane surface over a 6-month filtration period, which facilitated the self-cleaning of the NF by biodegrading foulants and loosening the fouling cake structure. This resulted in stabilized filtration without an increase in transmembrane pressure, highlighting the potential for cleaning-free and low-maintenance operation. Additionally, the RBF-NF process reduced energy consumption by 94.6 % and carbon emissions by 87.4 % compared to traditional NF processes, primarily through the reduction of driving pressure and the elimination of crossflow. These findings demonstrate that RBF-NF is an efficient, chemical-free, and nature-based water treatment technology with significant operational and environmental benefits.

RevDate: 2025-06-26

Anonymous (2025)

Correction to 'TasA Fibre Interactions Are Necessary for Bacillus subtilis Biofilm Structure'.

RevDate: 2025-06-26

Holley CL, Dhulipala V, Van AL, et al (2025)

Gentamicin induction of the gonococcal hicAB toxin-antitoxin encoding system and impact on gene expression influencing biofilm formation and in vivo fitness in a strain-specific manner.

bioRxiv : the preprint server for biology pii:2025.06.11.659166.

UNLABELLED: The continued emergence of Neisseria gonorrhoeae (Ng) isolates resistant to first-line antibiotics has focused efforts on understanding how alternative therapies such as expanded use of gentamicin (Gen) might counteract this global public health problem. Focusing on Gen as a viable alternative antibiotic for treatment of gonorrheal infections, we used RNA-Seq to determine if sub-lethal levels of Gen might impact gonococci on a transcriptional level. We found that sub-lethal Gen levels altered expression of 23 genes in Ng strain FA19. Many of the differentially regulated genes were associated with known stress responses elaborated by Ng under different harmful conditions. We found that the transcripts of the hicAB operon, which encodes a putative HicA-HicB toxin-antitoxin system that is encoded by tandem genes with the prophage Ngo φ3, were increased in response to Gen. While loss of hicAB did not impact gonococcal susceptibility to a variety of antimicrobial agents or harmful environmental conditions it did reduce biofilm formation in Ng strains F62, FA1090, WHO X and CDC200 but not that of strain FA19. Further, in strain F62, but not FA19, loss of hicAB reduced the in vivo fitness of Ng during experimental lower genital tract infection of female mice. Further, we found that expression of hicAB can influence levels of the norB transcript, which encodes the nitrate reductase shown previously to be upregulated in gonococcal biofilms. We propose that sub-lethal Gen has the capacity to influence gonococcal pathogenesis through the action of the HicAB toxin-antitoxin system.

IMPORTANCE: During antibiotic treatment bacteria can be exposed to sub-lethal levels that could serve as a stress signal resulting in changes in gene expression. The continued emergence of multi-drug resistant strains of Ng has rekindled interest in expanded use of gentamicin (Gen) for treatment of gonorrheal infections. We report that sub-lethal levels of Gen can influence levels of Ng transcripts including that of the gonococcal hicAB -encoded toxin-antitoxin (TA) locus, which is embedded within an integrated prophage, While loss of this TA locus did not impact Ng susceptibility to Gen it reduced the biofilm forming ability of 4/5 Ng strains. Further, in an examined strain in this group we found that Ng fitness during experimental infection was negatively impacted. We propose that that levels of the hicA-hicB transcripts can be increased by sub-lethal levels of an antibiotic used in treatment of gonorrhea and that this could influence pathogenicity.

RevDate: 2025-06-26

Xie J, Huang W, Liu S, et al (2025)

Supramolecular Nanoplatform for Biofilm Eradication and Anti-inflammatory by Phototherapies and Macrophage Repolarization.

Advanced healthcare materials [Epub ahead of print].

Biofilm dispersion and persistent inflammation are key challenges in treating bacterial infections. Phototherapies, including photodynamic therapy (PDT) and photothermal therapy (PTT), have emerged as promising approaches for treating bacterial infections. However, several challenges continue to impede the treatment effectiveness, particularly, the inevitable inflammatory side effects. Herein, a supramolecular nanoplatform (R-AuSTP-Be) is developed for precise targeting to bacterial infection sites, effective antimicrobial and anti-inflammatory for infected wound healing. R-AuSTP-Be can neutralize bacterial exotoxins for remodeling bacteria microenvironment, and disperse biofilms by precise phototherapies with dual-mode bacteria targeting by glycoprotein covalent bonding and electrostatic attraction. Meanwhile, R-AuSTP-Be reshapes the inflammatory environment by down-regulating M1 macrophage expression and up-regulating M2 macrophage expression. The excellent antibacterial and anti-inflammatory effects of R-AuSTP-Be provide a competitive strategy for treating bacterial infectious diseases.

RevDate: 2025-06-26

Seres-Steinbach A, Szabó P, Bányai K, et al (2025)

Effect of Temperature, Surface, and Medium Qualities on the Biofilm Formation of Listeria monocytogenes and Their Influencing Effects on the Antibacterial, Biofilm-Inhibitory, and Biofilm-Degrading Activities of Essential Oils.

Foods (Basel, Switzerland), 14(12):.

Listeria monocytogenes is a foodborne pathogen with a high tolerance to a wide range of environmental conditions, making its control in the food chain a particular challenge. Essential oils have recently been considered as potential antilisterial agents. In this study, the antilisterial effects of 57 EOs were tested on 13 different L. monocytogenes. Thirty-seven EOs were found to be effective in a strain and temperature-dependent manner. At 37 °C, all EOs were effective against at least one strain of L. monocytogenes. However, at 14 °C and 23 °C, 12 EOs, such as Minth, Nutmeg, Neroli, Pepperminth, etc., became drastically ineffective. The efficacy of the EOs increased at the lowest temperature, as only four EOs, such as Dill seed, Juniper, lemon eucalyptus, and sandalwood, were found to be ineffective at 4 °C. Ajowan and thyme were the only EOs that were antibacterial against each strain at all temperatures tested (4, 14, 23, 37 °C). Biofilm-inhibition tests with 57 EOs, performed on polystyrene plates with different surface qualities and stainless steel, using 0.1% and 0.5% final concentrations, showed the outstanding inhibitory abilities of ajowan, geranium, Lime oil, melissa, palmarosa, rose geranium, sandalwood, and thyme. Fennel, lemon eucalyptus, and chamomile had the potential to inhibit biofilm formation without affecting live bacterial cell counts. Ajowan, geranium, thyme, and palmarosa reduced the biofilm to the optical density of 0.0-0.08, OD: 0.0-0.075, 0.0-0.072, and 0.0-0.04, respectively, compared to the bacterium control 0.085-0.45. The mature antibiofilm eradication ability of the EOs revealed the outstanding features of ajowan, geranium Lime, melissa, palmarosa, rose geranium, and thyme by suppressing the established biofilm to one tenth. The different sensitivities of the isolates and the temperature-dependent antilisterial effect of the tested EOs have to be taken into account if an EO-based food preservation technology is to be implemented, as several L. monocytogenes become resistant to different EOs at medium temperature ranges such as 14 °C and 23 °C.

RevDate: 2025-06-26
CmpDate: 2025-06-26

Wilkinson D, Váchová L, Z Palková (2025)

Hostile Environments: Modifying Surfaces to Block Microbial Adhesion and Biofilm Formation.

Biomolecules, 15(6):.

Since the first observations of biofilm formation by microorganisms on various surfaces more than 50 years ago, it has been shown that most "unicellular" microorganisms prefer to grow in multicellular communities that often adhere to surfaces. The microbes in these communities adhere to each other, produce an extracellular matrix (ECM) that protects them from drugs, toxins and the host's immune system, and they coordinate their development and differentiate into different forms via signaling molecules and nutrient gradients. Biofilms are a serious problem in industry, agriculture, the marine environment and human and animal health. Many researchers are therefore investigating ways to disrupt biofilm formation by killing microbes or disrupting adhesion to a surface, quorum sensing or ECM production. This review provides an overview of approaches to altering various surfaces through physical, chemical or biological modifications to reduce/prevent microbial cell adhesion and biofilm development and maintenance. It also discusses the advantages and disadvantages of each approach and the challenges faced by researchers in this field.

RevDate: 2025-06-25

Meenatchi R, Priya PS, Appikatla NS, et al (2025)

Harnessing a deep-sea EAL-domain enzyme for quorum quenching and biofilm control in food pipelines.

International journal of food microbiology, 441:111326 pii:S0168-1605(25)00271-5 [Epub ahead of print].

This study explores the potential of quorum-quenching (QQ) enzymes from deep-sea bacteria to disrupt bacterial communication and biofilm formation. Among 21 psychrophilic marine isolates, Vibrio sp. strain SAT06 showed broad-spectrum QQ activity by degrading both short (C6-HSL) and long-chain (3-O-C12-HSL) acyl homoserine lactones. The QQ enzyme, identified as an EAL-domain-containing protein, exhibited high activity under refrigerated conditions (0-15 °C) and alkaline pH, further enhanced by Mg[2+] and Ca[2+] ions. Enzyme kinetics confirmed its hydrolytic activity against C6-HSL and 3-O-C12-HSL, validated by HPLC and acidification assays. SAT06 enzyme significantly reduced biofilm thickness (40-60 %) in Listeria monocytogenes and Pseudomonas fluorescens. It downregulated the agrA gene, a key regulator of biofilm formation in Gram-positive bacteria, and modified antibiotic resistance, restoring susceptibility in resistant pathogens. Mechanistically, the enzyme acts via lactone ring hydrolysis and modulates intracellular cyclic-di-GMP levels, as demonstrated by qualitative Congo red assays, thereby inhibiting quorum sensing-regulated biofilm formation and motility. The cold-active and stable nature of SAT06 under food processing conditions underscores its potential as an effective biofilm control agent. Future work may focus on enhancing enzyme durability through nanocoating for industrial deployment. This study also establishes a proof-of-concept for the SAT06 enzyme as a functional anti-biofilm surface coating within a model food-grade pipeline system.

RevDate: 2025-06-27
CmpDate: 2025-06-25

Dakheel KH, Rahim RA, Al-Obaidi JR, et al (2025)

Proteomic analysis reveals phage-driven metabolic shifts and biofilm disruption in methicillin-resistant Staphylococcus aureus (MRSA).

World journal of microbiology & biotechnology, 41(7):230.

Methicillin-resistant Staphylococcus aureus (MRSA) biofilms pose a severe risk to public health, showing resistance to standard antibiotics, which drives the need for novel antibacterial strategies. Bacteriophages have emerged as potential agents against biofilms, especially through their phage-encoded enzymes that disrupt the biofilm matrix, enhancing bacterial susceptibility. In this study, two bacteriophages, UPMK_1 and UPMK_2, were propagated on MRSA strains t127/4 and t223/20, respectively. Biofilms formed by these strains were treated with phages at specified concentrations, followed by protein extraction and analysis. Comparative proteomic profiling was performed using one-dimensional and two-dimensional SDS-PAGE, with protein identification facilitated by MALDI-TOF/TOF MS spectrometry, to observe biofilm degradation effects. Proteomic analysis revealed that phage treatment induced significant changes in biofilm protein expression, particularly with upregulated ribosome-recycling factors and elongation factors linked to enhanced protein synthesis, reflecting a reactivation of amino acid metabolism in the treated biofilms. This was marked by upregulated intracellular proteases like CIpL, which play a role in protein refolding and degradation, critical for phage progeny production and biofilm disruption. Phage treatment demonstrated notable effects on the metabolic and protein synthesis pathways within MRSA biofilms, suggesting that phages can redirect bacterial cellular processes to favour biofilm breakdown. This indicates the potential of bacteriophages as a viable adjunct to traditional antimicrobial approaches, particularly in combating antibiotic-resistant infections like MRSA. The study underscores the efficacy of bacteriophages as anti-biofilm agents, offering a promising strategy to weaken biofilms and combat antibiotic resistance through targeted disruption of bacterial metabolic pathways and biofilm integrity.

RevDate: 2025-06-27
CmpDate: 2025-06-25

Panariello B, Dias Panariello F, Misir A, et al (2025)

An Umbrella Review of E-Cigarettes' Impact on Oral Microbiota and Biofilm Buildup.

Pathogens (Basel, Switzerland), 14(6):.

E-cigarettes, a form of electronic nicotine delivery system (ENDS), have gained significant popularity, particularly among adolescents who often view vaping as a "cool" lifestyle choice. This growing trend has spurred extensive research on the effects of ENDS on both oral and systemic health. By synthesizing data from systematic reviews and meta-analyses, this umbrella review offers a comprehensive evaluation of the impact of e-cigarettes on oral biofilm accumulation and microbiota composition. A systematic search was conducted up to 12 March 2025, across PubMed/MEDLINE, Google Scholar, Cochrane Library, and Scopus for studies published between 2015 and 2025. Ten studies met the eligibility criteria. The quality of the selected papers, as assessed using the AMSTAR 2 tool, ranged from moderate to high. The findings of this review suggest that e-cigarette use may contribute to dysbiosis in the oral microbiota and foster biofilm accumulation, thereby increasing the risk of oral diseases such as periodontitis, peri-implantitis, oral candidiasis, and caries. The findings also highlight the need for further research into the long-term effects of e-cigarette use on oral health. This review is registered with PROSPERO (CRD420251025639).

RevDate: 2025-06-27
CmpDate: 2025-06-25

Kaczorek-Łukowska E, Foksiński P, Małaczewska J, et al (2025)

The Effects of Low Concentrations of Nisin on Biofilm Formation by Staphylococcus aureus Isolated from Dairy Cattle.

Pathogens (Basel, Switzerland), 14(6):.

Staphylococcus aureus is one of the aetiological agents of mastitis in dairy cattle. Their biofilms are relevant for human and veterinary medicine. It has been shown that some antibiotics at low concentrations can stimulate the production of biofilms, but there is little information on the effects of low concentrations of nisin, which is considered a therapeutic agent and has been added to food products for years as a biopreservative. In our study, we used Staphylococcus aureus strains (n = 28) isolated from dairy cattle. The MIC of nisin were determined using the broth microdilution method. Based on the minimum inhibitory concentration (MIC) results, the following concentrations were selected for further analyses: nisin at 39, 19, 9 IU/mL; nisin in combination with tetracycline at 39 IU/mL + 0.06 μg/mL, 18 IU/mL + 0.06 μg/mL, and 9 IU/mL + 0.06 μg/mL; and tetracycline alone at 0.06 μg/mL. The biofilm-forming capacity was determined via crystal violet staining in 96-well plates, icaD gene expression was determined using the 2-ΔΔCt method, and microscopic evaluation was carried out using scanning electron microscopy. Results: The MICs were 156 IU/mL (46%) and 312 IU/mL (43%) for most strains. Due to large statistical deviations, there were no statistically significant changes in the biofilm-forming capacity or icaD gene expression despite a visible increasing trend. Despite the absence of statistically significant differences, it was observed that for all concentrations analysed biofilm formation was noticeably greater for both nisin alone and for tetracycline and its mixtures than for untreated cells. Conclusions: In our opinion, the effects of nisin, especially at low concentrations, on biofilm structure show a certain worrying trend that may pose a future threat.

RevDate: 2025-06-25
CmpDate: 2025-06-25

Wełna J, Napiórkowska-Mastalerz M, Cyrankiewicz M, et al (2025)

Characteristic of Virulence and Parameters of Mixed Biofilm Formed by Carbapenem-Resistant Pseudomonas aeruginosa and Proteus mirabilis Strains Isolated from Infected Chronic Wounds.

Pathogens (Basel, Switzerland), 14(6):.

A biofilm is a group of bacterial cells in the polysaccharide matrix bonded to the surface (biotic or abiotic). Clinicians now realize that most infections are biofilm-related. Biofilm infections are often induced by more than one bacterial species. The aim of this study is to characterize a mixed biofilm composed of Pseudomonas aeruginosa and Proteus mirabilis strains. Forty-six isolates derived from chronic wound infections were cultivated to establish mature biofilms. The biofilm biomass and cell viability were measured by colorimetric assays. P. aeruginosa strains were tested for the presence of virulence and biofilm-related genes. The quorum sensing assay using the biosensor strain was also performed. A mixed biofilm of P. aeruginosa and P. mirabilis was visualized using fluorescence microscopy. Four groups of P. aeruginosa and P. mirabilis pairs, also visualized with fluorescence microscopy, were distinguished based on the biofilm biomass growth and metabolic activity loss. The exoY gene observed among P. aeruginosa isolates was connected to the metabolic activity loss of the biofilm. Generally, the interactions between P. aeruginosa and P. mirabilis species are not uniform. It is crucial to further research the interactions between microorganisms in biofilms. This may provide information on the mechanisms of biofilm formation in the complicated chronic wound environment.

RevDate: 2025-06-25

Barrera-Ortega CC, Rodil SE, Silva-Bermudez P, et al (2025)

Fluoride Casein Phosphopeptide and Tri-Calcium Phosphate Treatments for Enamel Remineralization: Effects on Surface Properties and Biofilm Resistance.

Dentistry journal, 13(6):.

Objectives: This study aimed to compare in vitro the protective effect of two enamel remineralizing agents, a varnish containing β-tricalcium phosphate with sodium fluoride (β-TCP-F) and a paste containing casein phosphopeptide-amorphous calcium phosphate with sodium fluoride (CPP-ACP-F), on artificially demineralized human enamel. Methods: A total of 120 human third molar enamel specimens were randomly assigned to four groups (n = 30 each): Group I (healthy enamel, control), Group II (initially demineralized, lesioned enamel), Group III (demineralized enamel and treated with β-TCP-F), and Group IV (demineralized enamel and treated with CPP-ACP-F). Groups II-IV underwent, for 15 days, a daily pH cycling regimen consisting of 21 h of demineralization under pH 4.4, followed by 3 h of remineralization under pH 7. Groups III and IV were treated with either β-TCP-F or CPP-ACP-F, prior to each 24 h demineralization-remineralization cycle. Fluoride ion release was measured after each pH cycle. Surface hardness, roughness, wettability, and Streptococcus mutans biofilm formation were assessed on days 5, 10, and 15 after a daily pH cycle. Results: CPP-ACP-F treatment showed a larger improvement in surface hardness (515.2 ± 10.7) compared to β-TCP-F (473.6 ± 12.8). Surface roughness decreased for both treatments compared to initially lesioned enamel; however, the decrease in roughness in the β-TCP-F group only reached a value of 1.193 μm after 15 days of treatment, a significantly larger value in comparison to healthy enamel. On the other hand, the decrease in roughness in the CPP-ACP-F treatment group reached a value of 0.76 μm, similar to that of healthy enamel. Contact angle measurements indicated that wettability increased in both treatment groups (β-TCP-F: 71.01°, CPP-ACP-F: 65.24°) compared to initially lesioned samples in Group II, reaching WCA values similar to or smaller than those of healthy enamel surfaces. Conclusions: Both treatments, β-TCP-F and CPP-ACP-F, demonstrated protective effects against enamel demineralization, with CPP-ACP-F showing superior enhancement of surface hardness and smoother enamel texture under in vitro pH cycling conditions. β-TCP-F varnish and CPP-ACP-F paste treatments counteracted surface modifications produced on human healthy enamel by in vitro demineralization.

RevDate: 2025-06-25

Arantes BBA, Cabral AKLF, Dos Santos KS, et al (2025)

Characterization of Biofilm Formation by the Dermatophyte Nannizzia gypsea.

Journal of fungi (Basel, Switzerland), 11(6):.

Dermatophytosis is a fungal infection that affects the skin, hair, and nails, impacting approximately 25% of the global population. Nannizzia gypsea is a geophilic fungus that can cause infections in humans and animals. Several studies have been conducted regarding its virulence, or ability to cause disease. This species may produce keratinolytic enzymes and form biofilms, which can increase resistance to treatment. Thus, this study focuses on investigating the biofilm formation of N. gypsea isolated from canine dermatophytosis using an ex vivo hair model, its biofilm extracellular matrix macromolecular contents, and the expression of genes involved in the colonization of keratinized surfaces. The biofilm was analyzed for metabolic activity using the XTT reduction assay, crystal violet staining to measure biofilm biomass, scanning electron microscopy (SEM), and the presence of polysaccharides, proteins, and extracellular DNA in the biofilm extracellular matrix. The virulence genes subtilisin 7, fungalysin (extracellular metalloproteinase), and efflux pump (Multidrug and Toxin Extrusion Protein 2) were evaluated by qPCR, comparing the planktonic and biofilm phenotypes. N. gypsea formed a robust biofilm, which matured after 5 days. Scanning electron microscopy (SEM) revealed the presence of an extensive extracellular matrix. In the hair model, the characteristic ectothrix parasitism of the species is observable. The gene expression analysis revealed a higher expression of all evaluated genes in the biofilm form compared to the planktonic form. Thus, N. gypsea exhibits a biofilm characterized by a robust extracellular matrix and high gene expression of factors related to pathogenesis and resistance.

RevDate: 2025-06-25

Nikoomanesh F, Sedighi M, Bourang MM, et al (2025)

Exploring the Antifungal Potential of Lawsone-Loaded Mesoporous Silica Nanoparticles Against Candida albicans and Candida glabrata: Growth Inhibition and Biofilm Disruption.

Journal of fungi (Basel, Switzerland), 11(6):.

The incidence of fungal infections is significantly rising, posing a challenge due to the limited class of antifungal drugs. There is a necessity to combat emerging resistant fungal infections by developing novel antifungal agents. This study aimed to evaluate the antifungal effects of lawsone (LAW), a natural component extracted from herbal medicine, and LAW-loaded mesoporous silica nanoparticles (LAW-MSNs) on growth, biofilm formation, and expression of ALS1 and EPA1 genes contributing to cell adhesion of Candida spp. Twenty C. albicans and twenty C. glabrata isolates, including ten fluconazole-resistant and ten fluconazole-susceptible isolates, were examined. The findings of the study indicated that LAW and LAW-MSNs inhibited Candida isolates growth at MIC range of 0.31->5 µg/mL and significantly reduced biofilm formation in C. albicans and C. glabrata. Moreover, both LAW and LAW-MSNs downregulated the expression of the adhesion genes ALS1 and EPA1 in C. albicans and C. glabrata. Based on the obtained findings, LAW emerged as a promising antifungal candidate. However, the nano-formulation (LAW-MSNs) improved its antifungal properties.

RevDate: 2025-06-25

Amin I, Abdelkhalek A, El-Demerdash AS, et al (2025)

Cellulose Nanocrystal/Zinc Oxide Bio-Nanocomposite Activity on Planktonic and Biofilm Producing Pan Drug-Resistant Clostridium perfringens Isolated from Chickens and Turkeys.

Antibiotics (Basel, Switzerland), 14(6):.

Background/Objectives:Clostridium perfringens is a normal inhabitant of the intestinal tract of poultry, and it has the potential to induce cholangiohepatitis and necrotic enteritis (NE). The poultry industry suffers significant financial losses because of NE, and treatment becomes more challenging due to resistant C. perfringens strains. Methods: The antimicrobial and antibiofilm activities of cellulose nanocrystals/zinc oxide nanocomposite (CNCs/ZnO) were assesses against pan drug-resistant (PDR) C. perfringens isolated from chickens and turkeys using phenotypic and molecular assays. Results: The overall prevalence rate of C. perfringens was 44.8% (43.75% in chickens and 58.33% in turkeys). Interestingly, the antimicrobial susceptibility testing of C. perfringens isolates revealed the alarming PDR (29.9%), extensively drug-resistant (XDR, 54.5%), and multidrug-resistant (MDR, 15.6%) isolates, with multiple antimicrobial resistance (MAR) indices ranging from 0.84 to 1. All PDR C. perfringens isolates could synthesize biofilms; among them, 21.7% were strong biofilm producers. The antimicrobial potentials of CNCs/ZnO against PDR C. perfringens isolates were evaluated by the agar well diffusion and broth microdilution techniques, and the results showed strong antimicrobial activity of the green nanocomposite with inhibition zones' diameters of 20-40 mm and MIC value of 0.125 µg/mL. Moreover, the nanocomposite exhibited a great antibiofilm effect against the pre-existent biofilms of PDR C. perfringens isolates in a dose-dependent manner [MBIC50 up to 83.43 ± 1.98 for the CNCs/ZnO MBC concentration (0.25 μg/mL)]. The transcript levels of agrB quorum sensing gene and pilA2 type IV pili gene responsible for biofilm formation were determined by the quantitative real time-PCR technique, pre- and post-treatment with the CNCs/ZnO nanocomposite. The expression of both genes downregulated (0.099 ± 0.012-0.454 ± 0.031 and 0.104 ± 0.006-0.403 ± 0.035, respectively) when compared to the non-treated isolates. Conclusions: To the best of our knowledge, this is the first report of CNCs/ZnO nanocomposite's antimicrobial and antibiofilm activities against PDR C. perfringens isolated from chickens and turkeys.

RevDate: 2025-06-25

Mulat M, Banicod RJS, Tabassum N, et al (2025)

Multiple Strategies for the Application of Medicinal Plant-Derived Bioactive Compounds in Controlling Microbial Biofilm and Virulence Properties.

Antibiotics (Basel, Switzerland), 14(6):.

Biofilms are complex microbial communities encased within a self-produced extracellular matrix, which plays a critical role in chronic infections and antimicrobial resistance. These enhance pathogen survival and virulence by protecting against host immune defenses and conventional antimicrobial treatments, posing substantial challenges in clinical contexts such as device-associated infections and chronic wounds. Secondary metabolites derived from medicinal plants, such as alkaloids, tannins, flavonoids, phenolic acids, and essential oils, have gained attention as promising agents against biofilm formation, microbial virulence, and antibiotic resistance. These natural compounds not only limit microbial growth and biofilm development but also disrupt communication between bacteria, known as quorum sensing, which reduces their ability to cause disease. Through progress in nanotechnology, various nanocarriers such as lipid-based systems, polymeric nanoparticles, and metal nanoparticles have been developed to improve the solubility, stability, and cellular uptake of phytochemicals. In addition, the synergistic use of plant-based metabolites with conventional antibiotics or antifungal drugs has shown promise in tackling drug-resistant microorganisms and revitalizing existing drugs. This review comprehensively discusses the efficacy of pure secondary metabolites from medicinal plants, both as individuals and in nanoformulated forms or in combination with antimicrobial agents, as alternative strategies to control biofilm-forming pathogens. The molecular mechanisms underlying their antibiofilm and antivirulence activities are discussed in detail. Lastly, the current pitfalls, limitations, and emerging directions in translating these natural compounds into clinical applications are critically evaluated.

RevDate: 2025-06-24
CmpDate: 2025-06-24

Liang Z, Zhao Y, Ji H, et al (2025)

Algae-bacteria symbiotic biofilm system for low carbon nitrogen removal from municipal wastewater: A review.

World journal of microbiology & biotechnology, 41(7):218.

The treatment of municipal wastewater has become a significant challenge due to its intricate composition and low carbon-to-nitrogen ratio. In order to meet the discharge standards, a large amount of energy is consumed. In this context, the incorporation of microalgae into the conventional activated sludge process has become a promising strategy for low-carbon denitrification. This study aims to integrate research on algal-bacterial symbiotic systems with biofilm technology to enhance energy-efficient nitrogen removal in municipal wastewater treatment. Through comprehensive analysis, this paper elucidates (1) the developmental dynamics of algal-bacterial symbioses, (2) the process of combining algal-bacterial symbiotic systems with biofilm systems, (3) the fundamentals and operational determinants of algal-bacterial symbiotic membrane systems, and (4) the potential applications in sustainable water treatment. The proposed hybrid system demonstrates significant potential for carbon-neutral wastewater treatment through synergistic pollutant degradation, offering an innovative approach to address critical challenges in environmental sustainability and water resource management.

RevDate: 2025-06-24
CmpDate: 2025-06-24

Xu J, Esnal JPP, Jin L, et al (2025)

New Insights Into Epiphytic Biofilm Formation, Composition, and Their Role in Submerged Macrophyte Decline Under Environmental Pollution.

Environmental microbiology, 27(6):e70121.

Over evolutionary time, submerged macrophytes and their epiphytic biofilms have developed complex interactions, particularly mutualistic interactions. However, environmental pollution can alter biofilms, potentially shifting their influence from supportive to neutral or even inhibitory. This change may be one of the significant driving factors for the decline of submerged macrophytes, yet a systematic review of this phenomenon is still lacking. To this end, we examine the formation and composition of epiphytic biofilms, summarize their effects on submerged macrophyte growth in freshwater lakes, and discuss how they mediate plant changes under increasing exposure to environmental pollution. Epiphytic biofilms, composed of complex biotic and abiotic components, influence submerged macrophytes by modifying light conditions and gas exchange, modulating nutrient competition and antioxidant responses, and releasing allelopathic substances; the magnitude of these effects varies with the biofilm's composition. Environmental pollution might favor resistant or fast-growing species that better compete for nutrients, impair light capture and gas exchange, and release harmful allelopathic substances. This diminishes the beneficial effects of epiphytic biofilms on submerged macrophytes, sometimes even resulting in detrimental impacts. This review examines how environmental pollution alters epiphytic biofilm composition and influences submerged macrophyte communities, providing novel insights into the dynamics of submerged macrophyte communities.

RevDate: 2025-06-25

Shatri AMN, Bere SK, Bouman D, et al (2025)

Antimicrobial, Time-Kill Kinetics, and Biofilm Inhibition Properties of Diospyros lycioides Chewing Stick Used in Namibia Against Enterococcus faecalis.

Journal of tropical medicine, 2025:7544856.

Background: Medicinal plants are used in Namibia for oral hygiene and to treat oral diseases. Validating the content and efficacy of medicinal chewsticks used in communities helps to provide proof of concept of medicinal plants used as a complementary/alternative medicine for oral diseases. Aim: This study presents the first report on quantified phytoconstituents, antimicrobial, time-kill kinetics, and biofilm inhibition properties of Diospyros lycioides organic and aqueous extracts against Enterococcus faecalis. Methodology: Dry plant materials were ground into powder and macerated in methanol and distilled water. Different phytoconstituents were quantified by Folin-Ciocalteu colorimetric method, ferric reducing antioxidant power assay, and DPPH free radical scavenging. An antibacterial assay was performed using the agar well diffusion method and a resazurin 96-well-based assay. Kill-time assay was done at various concentrations over 4 h. Biofilm inhibition was done using the crystal violet method. Results: Higher total flavonoid, total phenol contents, and free radical scavenging abilities were reported in methanol twig extracts. Inhibition zones of 28 ± 0.82 mm, with MICs of 15.6 ± 0.00 μg/mL, are reported against E. faecalis. The bactericidal endpoint of D. lycioides organic extracts for E. faecalis was reached after 4 h of incubation at 8 × MIC (124.8 μg/mL). These were comparable to the positive control, gentamicin. The organic extracts showed ≥ 50% biofilm inhibition against root canal-infecting E. faecalis at concentrations between 7.8 and 500 μg/mL, indicating strong biofilm inhibition. Conclusion: The study demonstrated that D. lycioides crude extracts have promising antibacterial properties and can eradicate E. faecalis biofilms in root canal treatments.

RevDate: 2025-06-23

Zhang Z, Liu B, Chen W, et al (2025)

Corrigendum to "Enhancing sewer low-loss transportation by food waste microencapsulation treatment: Dual suppression of organic leaching and biofilm architecture-function for mitigating hazardous gases and blockage risks" [Water Research Volume 282 (2025) 123749].

RevDate: 2025-06-24

Lu M, Feng Q, Qin F, et al (2025)

Enhanced denitrification and fouling control in hydrogen-based membrane biofilm reactor using novel flat membrane module.

Bioresource technology, 435:132848 pii:S0960-8524(25)00814-4 [Epub ahead of print].

In hydrogen-based membrane biofilm reactors (H2-MBfR), the most critical concerns revolve removal rate and membrane fouling. This study introduces a novel flat membrane module to enhance denitrification efficiency and the operational stability of MBfR. The membrane module featured an additional layer of polyester material on outer side of the membrane. Experimental results demonstrated that membrane fouling occurred after one week, while the flocking layer extended the fouling-free operation to over eight weeks, representing an eightfold improvement at least. Low temperature and high loading were observed to impact the denitrification efficiency, although it maintained around 50 % without nitrite accumulation. Following the removal of operational disturbances, the MBfR rapidly restored with removal efficiencies reaching 93.8 % to 100 %. As the MBfR operated, microbial analysis revealed a decrease in microbial diversity, and differential expression levels of denitrification genes. The novel membrane module contributed to improving fouling control and removal flux.

RevDate: 2025-06-24
CmpDate: 2025-06-24

Şenel K, Uzun I, R Alqawasmi (2025)

An in vitro evaluation of biofilm removal from simulated root canals using sodium hypochlorite irrigation solution at various temperature settings.

PloS one, 20(6):e0325431.

BACKGROUND: Using sodium hypochlorite (NaOCl) irrigation solution at various temperatures is common for removing biofilms in root canals and the isthmus. Numerous studies have examined the impact of temperature on biofilm removal in extracted teeth. However, this study aimed to assess the effect of needle irrigation using NaOCl solution heated to different temperatures on the structure of E. faecalis biofilm in artificial teeth produced by 3D printing technology.

MATERIALS AND METHODS: The isthmus in the mesial canals of 55 artificial tooth samples, which were produced from the 3D model obtained by micro-CT of the mandibular first molars, was evaluated. The standard strain E. faecalis ATCC 19433 was used to infect artificial tooth specimens. The samples were divided into a control group and four experimental groups receiving sodium hypochlorite solutions at 21°C, 45°C, 60°C, and 150°C. Following irrigation, scanning electron microscope (SEM) imaging was conducted at varying magnifications to visualize the remaining biofilm areas in the root canals and the isthmus. The ImageJ program quantified biofilm areas in the isthmus region. Statistical analyses, including Shapiro-Wilks, Kruskal Wallis H, and t-tests, were conducted on the measurements. A p-value of < 0.05 was considered statistically significant.

CONCLUSIONS: The results did not differ between the control and 21 °C groups (p > 0.05). However, removal areas were larger in the 45°C, 60°C, and 150°C groups than in the control group (p < 0.05). No difference was observed in the biofilm removal efficiency in different isthmus regions (p > 0.05). The findings revealed that an increase in temperature enlarged the removal areas.

RevDate: 2025-06-24
CmpDate: 2025-06-24

Nishizawa M, Saleh B, Marcucio R, et al (2025)

A Unique Mouse Model for Quantitative Assessment of Biofilm Formation on Surgical Implants in Subcutaneous Abscess.

Journal of visualized experiments : JoVE.

To develop a novel biomaterial with antibacterial properties for orthopedic surgical procedures, establishing an experimental animal model of implant-related infections that closely mimics the pathological state is crucial. Additionally, a quantitative comparison with control samples is required to assess biofilm formation on materials. However, current animal models, which involve implanting each individual with a single material, may yield inconsistent outcomes due to the heterogeneity of infection status among subjects. Furthermore, accurately quantifying biofilm formation on materials in vivo remains challenging, and the findings may lack reliability. To address these issues, this study demonstrated a unique mouse model of implant-related infection that enables the simultaneous incubation of two implants with bacteria in an enclosed environment within a single mouse, forming an encapsulated subcutaneous abscess. A mature air pouch was initially created beneath the skin of the back. Two stainless steel wires were connected and placed into the pouch, followed by the inoculation of Xen 36, a bioluminescent strain of Staphylococcus aureus. By 14 days after inoculation, a subcutaneous abscess had formed around the wires. The biofilm was completely removed from the surface of each wire, and the dissolved bacterial suspensions were accurately measured using optimized methods to assess biofilm formation on the implant, determine colony-forming units, and perform quantitative polymerase chain reaction analysis. By leveraging the lux operon of the bioluminescent bacteria, the relative expression levels of luxA and 16S rRNA were used to determine the bacterial load within the biofilm on each wire. This optimized comparative analytical approach enables precise assessments of biofilm formation on two wires under uniform infection conditions within a single mouse model and may facilitate the advancement of biomaterials with antibacterial properties.

RevDate: 2025-06-24
CmpDate: 2025-06-24

Abban MK, Ayerakwa EA, A Isawumi (2025)

Biofilm and surface-motility profiles under polymyxin B stress in multidrug-resistant KAPE pathogens isolated from Ghanaian hospital ICUs.

Experimental biology and medicine (Maywood, N.J.), 250:10350.

The threat of antimicrobial resistance in Ghana is increasing with the recent emergence of KAPE pathogens (K. pneumoniae, A. baumannii, P. aeruginosa and Enterobacter species) from the hospital environment. As opportunistic pathogens, KAPE leverage the formation of biofilms and swarms to survive stringent environmental conditions. As research continues to investigate approaches that bacteria employ to exacerbate infection, this study explored biofilm and swarm formation in MDR KAPE pathogens under polymyxin B stress emerging from Ghanaian hospitals. The antimicrobial susceptibility profile of KAPE pathogens to conventional antibiotics and polymyxin B was investigated via antibiotic disk diffusion and broth microdilution assays. Biofilm inhibition and eradication assays, swarm motility and a resazurin-based metabolic assay were used to profile bacterial phenotypic characteristics under polymyxin B stress. The strains exhibited resistance to the tested antibiotics with a high level of resistance to polymyxin B (PMB) (≥512 μg/mL). Additionally, the strains formed biofilms and bacterial swarms at 37°C. In the presence of PMB (≥512 μg/mL), KAPE pathogens formed swarms with no significant reduction in bacterial swarms at 1,048 μg/mL. Biofilm was observed for all strains with PMB neither inhibiting nor eradicating at high PMB (2048 μg/mL). Additionally, there were no significant differences in the phenotypic and antimicrobial susceptibility profiles of clinical and environmental KAPE pathogens from Ghanaian ICUs. Overall, the study established that clinical and environmental KAPE pathogens from Ghanaian ICUs exhibit adaptive phenotypic and resistance characteristics that could potentially enhance bacterial survival during host colonization and infection. This could undermine treatment strategies and pose public health challenges in Ghana.

RevDate: 2025-06-23

Thibodeau AJ, Mouchet F, Nguyen VX, et al (2025)

Experimental assessment of antibiotic resistance in a Biofilm - Grazer system.

Environmental pollution (Barking, Essex : 1987) pii:S0269-7491(25)01055-3 [Epub ahead of print].

Antimicrobial resistance (AMR) is a growing global health threat, with environmental compartments such as soil, water, and biofilms playing key roles in the dissemination and persistence of resistance genes. In this study, we explored the dynamics of AMR within a controlled Biofilm-Grazer system using Xenopus laevis larvae and biofilms A and B collected from two distinct rivers in Occitanie, France (collected respectively upstream from the large city of Toulouse and downstream from a wastewater treatment plant). The objective of the study was to investigate bacterial interactions between gut microbiota and biofilms, as well as the modulation of ARG (Antibiotic Resistance Gene) abundance and diversity over a 12-day period. Results showed a decrease of resistome in Xenopus gut microbiota feeding on both biofilms compared to feeding on commercial feed. In addition, an increase of resistome of Biofilm B compared to Biofilm A was observed. Procruste analysis and Pearson's correlations revealed a link between bacterial communities changes and ARG abundances in biofilms. Rhodobacter genus could be an ARG host shared between compartments. Furthermore, bacterial immigration predominantly occurred from the gut to the biofilms, with both biofilms acting as reservoirs for ARGs. Notably, Biofilm B, collected from a more polluted river, demonstrated a higher relative abundance of aac3-IVa resistance genes in the gut microbiota of larvae, compared to Biofilm A and a higher immigration rate from biofilm to gut. These findings highlight the complexity of interactions between biofilm communities and the gut microbiota, which may influence AMR dissemination.

RevDate: 2025-06-25

Peng P, Yan X, Chen L, et al (2025)

Electroactive biofilm enhances synergistic degradation of sulfamethoxazole and roxarsone in actual livestock wastewater: extracellular electron transfer drives metabolic network remodeling.

Environmental research, 284:122173 pii:S0013-9351(25)01424-0 [Epub ahead of print].

Livestock wastewater is characterized by high concentrations of organic matter and diverse antibiotics. A major challenge in its anaerobic treatment is the effective degradation and thorough removal of coexisting antibiotic contaminants. In this study, an external voltage was applied to establish an electroactive biofilm, thereby enhancing the co-metabolic degradation of sulfamethoxazole and roxarsone. Application of +0.6 V (Ag/AgCl) increased the 72 h TOC removal efficiency to 52.1 %. At the same time, sulfamethoxazole and roxarsone removal efficiencies reached 90.8 % and 100 %, respectively. The results from liquid chromatography-mass spectrometry (HPLC-MS/MS) and density functional theory calculations revealed sulfamethoxazole degradation pathways: N-O bond cleavage and hydroxylation. Roxarsone degradation primarily involved nitro group reduction and C-As bond cleavage. The pharmacophore of sulfamethoxazole was effectively removed, and inorganic arsenic from roxarsone degradation was efficiently immobilized. Toxicity analysis confirmed that the electroactive biofilm notably reduced toxic intermediate accumulation. Elevated concentrations of NADH and ATP in the electroactive biofilm indicated enhanced microbial substrate metabolism and generation of more electron donors. The higher absolute abundance of the sulfamethoxazole degradation gene (SadABC) in the electroactive biofilm indicated that sulfamethoxazole degrading enzyme (sadABC) gained more electrons. Microbiome analysis revealed the upregulation of genes linked to extracellular electron transfer, the tricarboxylic acid (TCA) cycle, nitro-reduction, and sulfate reduction pathway, confirming the electroactive biofilm enhances substrate metabolism and co-metabolic antibiotic degradation. Electroactive biofilm offers a viable strategy for antibiotic removal in livestock wastewater.

RevDate: 2025-06-23

Zhang H, Jiang H, Jin L, et al (2025)

Self-corroding microelectrolysis enhanced membrane aeration electroactive biofilm for antibiotic and antibiotic resistance gene reduction.

Bioresource technology pii:S0960-8524(25)00821-1 [Epub ahead of print].

A three-dimensional bioelectrochemical system was developed by coupling self-corrosive Fe/C microelectrodes with a membrane-aerated electroactive biofilm reactor (IC-MAEBR) to enhance antibiotic and antibiotic resistance gene (ARG) reduction. The IC-MAEBR significantly enriched aromatic proteins as dominant fluorescent components in cathode biofilms, while exhibiting an elevated α-helix to (β-sheet + random coil) (62.8 %), enhanced biofilm dense. Besides, the coordinated action of applied potential and microelectrolysis reduced sul1 and sul2 abundances in cathode biofilms by -2.6 log2 and -1.6 log2, respectively, primarily through host microorganism inactivation. Although higher potential differences (0.75 V) narrowed SMX removal difference between membrane-aerated electroactive biofilm reactors (MAEBR) and IC-MAEBR, IC-MAEBR demonstrated superior performance at lower potentials (0.5 V), achieving rapid SMX degradation within 12 h and maintained accelerated removal kinetics even post-discharge cycles, outperforming MABR and MAEBR by 4.2 μg/L/h and 9.7 μg/L/h, respectively. This study provides new insights into microelectrolysis enhanced electroactive-biofilm in antibiotics and ARGs removal.

RevDate: 2025-06-23

Pu Y, Feng F, Hou Y, et al (2025)

Impact of yeast extract on bacterial metabolism and nickel microbiologically influenced corrosion: Insights into medium optimization and biofilm electron transfer mechanism.

Bioelectrochemistry (Amsterdam, Netherlands), 166:109027 pii:S1567-5394(25)00130-6 [Epub ahead of print].

Yeast extract (YE) serves as a complex nutrient source and plays a pivotal role in the formation and development of microbial biofilms. This work elucidates the critical role of YE in modulating the metabolic activity of Desulfovibrio vulgaris, characteristics of passive films, and the associated microbiologically influenced corrosion (MIC) behavior of nickel (Ni). The presence of YE suppresses corrosion processes linked to extracellular electron transfer (EET) by reducing the necessity for D. vulgaris to directly extract electrons from Ni. In the absence of YE, a greater number of D. vulgaris cells adhere to the Ni surface, forming biofilms with an increased reliance on EET from Ni, thereby exacerbating localized corrosion. This is evidenced by increased weight loss, deeper pitting, and elevated localized corrosion current density, establishing a clear correlation between YE availability and the mitigation of EET-mediated MIC. Meanwhile, YE mitigates EET-driven corrosion by regulating the biofilm structure, facilitating the formation of a protective layer, and modifying the passive film on Ni. A key implication of this work is the reconsideration of YE as a universal nutrient in MIC research, emphasizing the need for caution when using YE in MIC studies that focus on EET-driven mechanisms.

RevDate: 2025-06-24
CmpDate: 2025-06-24

Saci S, Houali K, Schena R, et al (2025)

Phenotypic and genotypic characterization of biofilm-producing avian pathogenic Escherichia coli (APEC) isolates from Algerian poultry: associations between antimicrobial resistance and virulence genes.

Veterinary research communications, 49(4):232.

Avian colibacillosis, caused by avian pathogenic Escherichia coli (APEC), represents a major threat to the poultry industry, leading to significant economic losses. This study aimed to characterize selected biofilm-producing APEC strains isolated from diseased chickens in the Tizi-Ouzou region of Algeria and to explore potential associations between antimicrobial resistance and the presence of virulence factors. Twenty-four confirmed biofilm-producing E. coli isolates were analyzed for serotype distribution, antimicrobial resistance patterns and virulence gene profiles. While none belonged to the O157 serogroup, all isolates demonstrated concerning resistance profiles, with high rates observed for tetracycline (83.3%), ampicillin (75%), and ciprofloxacin (62.5%). Notably, 40% of the strains exhibited biofilm-forming capability, predominantly showing weak to moderate production levels.Virulence gene profiling revealed traT, bcsA, and csgA as nearly ubiquitous (95.8%), with fimH present in 83.3% of isolates. Intermediate prevalence was noted for iutA (62.5%), fliC (45.8%), and agn43 (33.3%), while fyuA (29.2%) and several other virulence markers (kpsMT II, papC, cnf1, ibeA) occurred at lower frequencies (< 10%). Statistical analysis identified significant correlations between virulence gene content and phenotypic characteristics, including a positive association between virulence gene number and biofilm intensity (p < 0.05). Moreover, the fimH gene showed a strong positive correlation with resistance to the antibiotic nalidixic acid. Resistance to β-lactam antibiotics (cefotaxime, cefepime, aztreonam) was positively correlated (p < 0.05) with papC and ibeA, but negatively correlated with csgA. These findings underscore the complex interplay between antimicrobial resistance and virulence in Algerian biofilm-producing APEC strains, highlighting the need for enhanced surveillance programs and tailored intervention strategies. This study provides critical baseline data for developing effective control measures against colibacillosis poultry production systems.

RevDate: 2025-06-23

Olivan-Muro I, Guío J, Alonso-Tolo G, et al (2025)

Towards the control of biofilm formation in Anabaena (Nostoc) sp. PCC7120: novel insights into the genes involved and their regulation.

The New phytologist [Epub ahead of print].

Cyanobacteria are major components of biofilms in light-exposed environments, contributing to nutrient cycling, nitrogen fixation and global biogeochemical processes. Although nitrogen-fixing cyanobacteria have been successfully used in biofertilization, the regulatory mechanisms underlying biofilm formation remain poorly understood. In this work, we have identified 183 novel genes in Anabaena sp. PCC7120 potentially associated with exopolysaccharide (EPS) biosynthesis and biofilm formation, unveiling conserved and novel regulatory connections shared with phylogenetically distant bacteria. Anabaena possesses homologues of two-component systems such as XssRS and ColRS from Xanthomonas spp., and AnCrpAB from Methylobacillus, suggesting that these homologues play essential or advantageous roles in biofilm formation across diverse bacterial lineages. Additionally, Anabaena features homologues of several proteins exhibiting the GG-secretion motif typical of small proteins required for biofilm formation in unicellular cyanobacteria. A wide array of biofilm-related genes in Anabaena, including major gene clusters participating in the synthesis and translocation of EPS and key regulatory proteins involved in the control of biofilms in other bacteria are modulated by ferric uptake regulator proteins. These findings link the control of biofilm formation in Anabaena to environmental cues such as metal availability, desiccation and nitrogen levels, providing new insights to improve the use of nitrogen-fixing cyanobacterial biofilms in sustainable agriculture and environmental management.

RevDate: 2025-06-24
CmpDate: 2025-06-24

Ranava D, Lander SM, Kuan SY, et al (2025)

A promiscuous Bcd amino acid dehydrogenase promotes biofilm development in Bacillus subtilis.

NPJ biofilms and microbiomes, 11(1):112.

Glutamate dehydrogenase (GDH) resides at the crossroads of nitrogen and carbon metabolism, catalyzing the reversible conversion of L-glutamate to α-ketoglutarate and ammonium. GDH paralogs are ubiquitous across most species, presumably enabling functional specialization and genetic compensation in response to diverse conditions. Staphylococcus aureus harbors a single housekeeping GDH (GudB), whereas Bacillus subtilis encodes both a major and a minor GDH, GudB and RocG, respectively. In an unsuccessful attempt to identify an alternative GDH in S. aureus, we serendipitously discovered previously unrecognized GDH activity in two metabolic enzymes of B. subtilis. The hexameric Val/Leu/Ile dehydrogenase Bcd (formerly YqiT) catabolizes branched-chain amino acids and to a lesser extent glutamate using NAD[+] as a cofactor. Removal of gudB and rocG unmasks the dual NAD(P)[+]-dependent GDH activity of RocA, which otherwise functions as a 3-hydroxy-1-pyrroline-5-carboxylate dehydrogenase. Bcd homologs are prevalent in free-living and obligate bacteria but are absent in most, if not all, staphylococci. Despite low sequence homology, Bcd structurally resembles the GudB/RocG family and can functionally compensate for the loss of GudB in S. aureus. Bcd is essential for the full maturation of biofilms. B. subtilis lacking GDHs exhibits severe impairments in rugose architecture and colony expansion of biofilms. This study underscores the importance of metabolic redundancy and highlights the critical role of substrate promiscuity in GDHs during biofilm development.

RevDate: 2025-06-23

Yawen Z, Tiantian S, Yangyang S, et al (2025)

Dodecylmethylaminoethyl methacrylate inhibits the growth of Candida albicans and Enterococcus faecalis biofilm and the formation of osteoclast.

Archives of oral biology, 177:106331 pii:S0003-9969(25)00159-1 [Epub ahead of print].

OBJECTIVES: This study aimed to evaluate the antimicrobial ability on the dual-species biofilm formed by C. albicans and E. faecalis and osteoclysis inhibition of DMAEM.

DESIGN: DMAEM monomer was used to evaluate the antmicrobial ability on the dual-species biofilm of C. albicans and E. faecalis by biomass quantification, Scanning electron microscope and confocal laser scanning microscopy scanning, and RT-qPCR. The biosafty and inhibition ability on the dual-species biofilm and osteoclysis of the experimental root canal sealers containing DMAEM was tested by biomass quantification, Cell Counting kit-8, tartrate-resistant acid phosphatase staining, flow cytometry analysis, and RT-qPCR.

RESULTS: The biomass of the dual-species biofilm formed by C. albicans and E. faecalis was significantly decreased by 26.3-51.3 % under 8-256 μg/mL DMAEM. 8 μg/mL DMAEM could reduce E. faecalis's survival rate to 77.4 % (p < 0.001) and down-regulated its virulence gene expression. Meanwhile, the mycelium count proportion of C. albicans in the dual-species biofilm was reduced from 50 % to 0 % (p < 0.0001). The experimental sealers with DMAEM content could also decrease the survival rate of C.albicans and E.faecalis in the dual-species biofilm. Moreover, the elution of experimental root canal sealers containing ≤ 2.5 % DMAEM was biosafe and improved 81.0 % (p < 0.05) osteoclastic inhibition compared with it of unmodified sealers at least.

CONCLUSIONS: The antimicrobial ability on the dual-species biofilm formed by C. albicans and E. faecalis and osteoclastic inhibition of DMAEM suggested its potential clinical application of DMAEM in the treatment of periapical inflammation.

RevDate: 2025-06-23

Zhang S, Li Y, Jiang L, et al (2025)

Insights on the characteristics of plastic surface degradation and biofilm microorganisms: Exploring the impacts of three aerobic composting (AC) as well as UV irradiation and cycles of freeze-thaw (CFTs).

Journal of hazardous materials, 495:138960 pii:S0304-3894(25)01876-X [Epub ahead of print].

Organic fertilizers applied to soil often contain significant amounts of plastics, which typically undergo a process of aerobic composting (AC) that induces specific physical and chemical changes on their surfaces. In this study, we simulated the environmental actions of AC source plastic film under typical soil environmental exposure, exploring how AC affects the response of plastics to ultraviolet (UV) radiation and cycles of freeze-thaw (CFTs). The results showed that varying composting conditions significantly impacted the fungal and bacterial community structures on the plastic surface; and plastic degradation under AC present various surface properties, including embrittlement, wear, corrosion, and reduced transparency, with specific yellowing and breakage, and strong microbial adhesion. UV exposure exacerbated the degradation of plastics sourced from AC. Plastics subjected to both AC and UV displayed significant changes after experiencing intense stress from CFTs. The structures of polyethylene (PE) and polylactic acid (PLA) were severely disrupted, resulting in the formation of powder or debris. Moreover, PLA and polyvinyl chloride (PVC) showed slightly reduced yellowing and unsaturation, while releasing total dissolved solids (TDS), micro/nanoplastics and additives. This study highlights the distinct characteristics of plastic pollution originating from AC processes associated with organic fertilizer land-use.

RevDate: 2025-06-23

Adams CO, Campbell JA, Zhang B, et al (2025)

Legionella pneumophila type II secretome reveals a polysaccharide deacetylase that impacts intracellular infection, biofilm formation, and resistance to polymyxin- and serum-mediated killing.

mBio [Epub ahead of print].

Prior analyses suggested that the type II secretion system (T2SS) of Legionella pneumophila secretes ≥47 proteins beyond its 26 known substrates. Upon examination of mutants of wild-type strain 130b that lack those exoproteins most conserved across the Legionella genus, we discovered that protein "06635" majorly promotes L. pneumophila replication within amoebae. Immunoblotting, proteomics, and whole-cell enzyme-linked immunosorbent assay (ELISA) confirmed that 06635 exists in culture supernatants and on the bacterial outer surface and does so in a T2SS-dependent manner. Bioinformatic analyses identified 06635 as a novel member of the carbohydrate esterase family 4, whose members deacetylate bacterial surface polysaccharides, peptidoglycan, chitins, and/or xylans. Given 06635's T2SS-dependent secretion, low-level amino acid similarity to known peptidoglycan deacetylases, and the unaltered lysozyme resistance of a 06635 mutant, we pursued the hypothesis that 06635 deacetylates a polysaccharide on L. pneumophila's surface. Supporting this, the 06635 mutant exhibited increased binding to both wheat germ agglutinin (i.e., more surface N-acetylglucosamine) and antibodies that recognize acetylated lipopolysaccharide (LPS). Nuclear magnetic resonance (NMR) analysis of isolated mutant vs wild-type LPS confirmed that 06635 promotes LPS deacetylation. Thus, we designated 06635 as PdaA, for polysaccharide deacetylase A. Compatible with its altered surface, the pdaA mutant showed greater autoaggregation, increased biofilm formation, and heightened sensitivity to both polymyxin and human serum. Thus, we hypothesize that, following its secretion via the T2SS, PdaA deacetylates LPS, and perhaps other moieties, impacting many significant processes. While defining PdaA, we identified many more putative substrates of the L. pneumophila T2SS, bringing the size of the T2SS output to approximately 120.IMPORTANCELegionella pneumophila is the principal cause of Legionnaires' disease, an increasingly common form of pneumonia. Although prior work demonstrated that the bacterium utilizes its type II protein secretion system (T2SS) to survive in aquatic environments and to cause lung infection, the full scope and impact of this Legionella secretion system is still relatively underappreciated. By utilizing an expanded proteomic approach and testing newly made mutants in a wide range of assays, we have determined that the L. pneumophila type II secretome encompasses approximately 120 proteins, and among these proteins is a novel polysaccharide deacetylase (PdaA) that modulates the L. pneumophila surface and lipopolysaccharide, impacting intracellular infection, biofilm formation, and resistance to both antibiotics and human serum. Moreover, since T2SSs and homologs of PdaA were found in many other bacteria, our findings should also have implications for understanding other infectious diseases and environmental processes.

RevDate: 2025-06-24

Jordana-Lluch E, Escobar-Salom M, Torrens G, et al (2025)

Corticosteroids modulate biofilm formation and virulence of Pseudomonas aeruginosa.

Biofilm, 9:100289.

Corticosteroids are anti-inflammatory drugs commonly administered to patients with chronic obstructive pulmonary disease (COPD), cystic fibrosis and similar lung pathologies, in which persistent infections with Pseudomonas aeruginosa are frequent. However, their therapeutic value is debatable because of their adverse impact on host immunity. The aim of this work was to determine the impact of budesonide and fluticasone propionate on P. aeruginosa biology. We found that these corticosteroids attenuated its intrinsic pro-inflammatory properties (reduction of IL-8 release compared to controls ca. 15 % (budesonide) and 50 % (fluticasone propionate)) and cellular invasiveness (25 % and 40 % respectively). Corticosteroids enhanced P. aeruginosa biofilm formation in a time/dose-dependent manner (around 1.6-fold for the highest concentration, with this increase occurring more readily in sputum media)) and stimulated the release of extracellular DNA (2-fold increase), a key component of the biofilm matrix. Regarding the mechanisms involved, our results suggest that corticosteroids diffuse through P. aeruginosa's membrane influencing its fluidity and triggering cell envelope stress signalling pathways, as shown by an initial increase in mucA (σ[22] regulon) expression, outer membrane vesicle release and accumulation of cyclic diguanylate (c-di-GMP). Changes in the levels of this intracellular signalling molecule, responsible for the switch from planktonic to biofilm lifestyle, may explain some of the phenotypes observed. In conclusion, our data, first obtained with type strains and proved to be reproducible when using COPD clinical isolates, suggest that corticosteroids could mediate a faster acquisition of the phenotypic characteristics associated with P. aeruginosa long-term adaptation to the chronic lung niche without undergoing mutation.

RevDate: 2025-06-20

Sun S, Xin Q, Ma Z, et al (2025)

Self-Assembled Photothermal Particles Boost Synergistic Biofilm Eradication and Remineralization in Early Dental Caries Treatment.

Small (Weinheim an der Bergstrasse, Germany) [Epub ahead of print].

Dental caries, driven by dietary habits and microbial biofilms, remains a significant global health issue. In situ biomimetic remineralization is considered a promising method, but its low efficiency is a key challenge. Additionally, the interference of cariogenic bacteria further exacerbates the problem. In this study, self-assembled photothermal particles (PAEB) with light-boosted synergistic biofilm eradication and remineralization properties for caries treatment are reported. Composed by polyaspartic acid-stabilized amorphous calcium phosphate (Pasp-ACP) and ε-poly-L-lysine/baicalein (EPL-BC), PAEB enable efficient light-to-heat conversion under near-infrared light exposure due to polymerization and stacking of baicalein. The localized hyperthermia, accompanied with EPL-BC disrupts bacterial membranes and eradicates biofilm by more than 99%, which is seven times higher than the non-radiation group (12.86%) and ≈21 times higher than the fluoride group (4.35%). Meanwhile, the releasing of calcium and phosphate ions is accelerated for rapid remineralization, with highest hardness recovery (1.96 GPa) of all groups, comparable to untreated healthy enamel. Moreover, in vivo microbiome analysis confirms that PAEB selectively reduces the abundance of cariogenic Streptococcus spp. while maintaining overall microbial diversity and oral ecological balance, presenting a promising solution for non-invasive dental caries treatment. This photothermal-enhanced strategy gives a reference for the design of bioactive therapeutic dental materials.

RevDate: 2025-06-20

Zhao X, He G, Liu B, et al (2025)

The Influence of SDM on the Performance of the EGSB-Two-Stage A/O Biofilm Process for Pig Wastewater Treatment and Mechanism Investigation.

Water environment research : a research publication of the Water Environment Federation, 97(6):e70127.

To address the treatment of pig wastewater containing high levels of organic matter, this study investigated the impact of sulfadimethoxine (SDM) on the performance and underlying mechanisms of an expanded granular sludge bed (EGSB) combined with a two-stage anoxic/oxic (A/O) biofilm process. The reactor demonstrated robust organic loading tolerance (up to 12,195 mg/L COD) while maintaining stable treatment performance, achieving > 95% COD removal efficiency and 70%-80% ammonia nitrogen (NH3-N) elimination. Systematic analysis of sludge microstructure and microbial consortia was conducted through integrated techniques, including scanning electron microscopy (SEM) and high-throughput sequencing. The introduction of SDM induced significant restructuring of microbial architecture and population dynamics, with Proteobacteria (21.73%-89.74%), Firmicutes (5.54%-33.53%), Chloroflexi (1.22%-23.07%), Bacteroidetes (2.48%-12.23%), and Synergistetes (15.64%-26.86%) emerging as dominant phyla. Notably, Proteobacteria and Firmicutes demonstrated superior resistance under the reaction process. Concurrently, microbial analysis revealed a significant enrichment of nitrogen-phosphorus-removing genera Acinetobacter and Pseudomonas during the reaction process, establishing that these bacterial taxa play a central role in the biodegradation of organic pollutants. Therefore, the microorganisms exhibited adaptability to high-load antibiotic-containing environments, substantiating the hybrid reactor's potential for livestock and poultry breeding wastewater treatment. SUMMARY: The presence of antibiotics reduces the removal of conventional pollutants by the combined process. Antibiotics cause changes in microbial population structure. EGSB-two-stage A/O combination process can effectively treat high organic load wastewater.

RevDate: 2025-06-19

Li CH, Chao WH, Wu PC, et al (2025)

Remote biofilm dislodgment using focused acoustic vortex.

Ultrasonics sonochemistry pii:S1350-4177(25)00202-0 [Epub ahead of print].

Biofilms constitute a major challenge in treating implant-associated and chronic infections due to their structural resilience and drug resistance, particularly as implant demand rises due to aging populations. Conventional methods are often invasive, complex, and costly, while focused ultrasound (FUS) poses risks related to biocompatibility and tissue damage. Distinguished by its helical phase structure and rotational energy distribution, focused acoustic vortex (FAV) theoretically generates stronger rotational forces and acoustic streaming than FUS under identical acoustic conditions. This study investigates the feasibility of FAV technique for biofilm removal. Biofilms in vitro model were established using Escherichia coli, and a 2-MHz custom-built ultrasound transducer was employed to generate either FAV or FUS. Results indicated that FAV activation generated a centripetal vortical flow with rapid rotation, which was adjustable via acoustic pressure and duty cycle. Conversely, FUS generated solely outward acoustic streaming, exhibiting a flow velocity 43.6 % lower than that of FAV. At 1.75 MPa, implementing a 10 % duty cycle and a 180 s treatment, FAV removed 97 % of the biofilm, whereas FUS removed only 7 %. To achieve a comparable removal rate (95.8 %), FUS required 4 MPa for 10 minutes. Streaming velocity (R[2] = 0.99) exhibited a strong correlation with biofilm removal, while inertial cavitation (R[2] = 0.19) exhibited a weak correlation; thus, the former was identified as the primary contributing mechanism. Importantly, FAV treatment resulted in minimal thermal elevation (<5 °C) and no significant reduction in cell viability, demonstrating its biosafety under the applied acoustic parameters. Synergistic tests with antibiotics further suppressed biofilm regrowth for up to 72 h, reducing bacterial concentration by 91 %. Future work will focus on in vivo biofilm models and assessing the safety and efficacy of combined treatments to advance clinical applications.

RevDate: 2025-06-20

Alshehri T, Alkhalifah I, Alotaibi A, et al (2025)

The impact of Caralluma munbyana extracts on Streptococcus mutans biofilm formation.

Frontiers in dental medicine, 6:1575161.

BACKGROUND/OBJECTIVES: Caralluma plants have a wide range of anti-inflammatory and antimicrobial activities. This study aims to assess the antibacterial effect of water, methanol, and ethanol extracts of Caralluma munbyana against Streptococcus mutans biofilms.

METHODS: Three extracts of C. munbyana were prepared using water, methanol, and ethanol. Multiple concentrations ranging between 2.93 and 93.75 mg/ml were achieved, alongside a control group with no extract, and incubated with an overnight culture of S. mutans. In the following day, the total absorbance was measured at 595 nm. Then, the biofilms were fixed and stained with 0.5% crystal violet to measure the biofilm absorbance at 490 nm. One-way ANOVA and Tukey's post-hoc tests were applied to identify which specific concentrations differed from the control.

RESULTS: C. munbyana methanol and ethanol extracts significantly affected the total absorbance of S. mutans (P ≤ 0.001) at 46.87 and 93.75 mg/ml. For biofilm inhibition, C. munbyana water extract was effective (P ≤ 0.001) in reducing the biofilm growth at 23.44 (1.34 ± 0.08), 46.87 (1.31 ± 0.15), and 93.75 (1.04 ± 0.07) mg/ml when compared to the control (1.58 ± 0.11). More reduction was observed among methanol and ethanol extracts, as C. munbyana methanol extract significantly (P ≤ 0.001) inhibited the S. mutans biofilm growth at 23.44 (0.99 ± 0.15), 46.87 (0.12 ± 0.02), and 93.75 (0.09 ± 0.01) mg/ml. Similarly, C. munbyana ethanol extract's biofilm inhibition was observed at the concentrations of 23.44 (0.45 ± 0.12), 46.87 (0.10 ± 0.02), and 93.75 (0.09 ± 0.04) mg/ml.

CONCLUSION: These findings suggest that C. munbyana possesses antibacterial properties against S. mutans biofilms, particularly through its methanol and ethanol extracts.

RevDate: 2025-06-19

Abdelrazek HM, Ghozlan HA, Sabry SA, et al (2025)

Retraction notice to "Copper oxide nanoparticles (CuO-NPs) as a key player in the production of oil-based paint against biofilm and other activities" [Heliyon 10 (2024) e29758].

Heliyon, 11(9):e43267 pii:S2405-8440(25)01650-0.

[This retracts the article DOI: 10.1016/j.heliyon.2024.e29758.].

RevDate: 2025-06-21
CmpDate: 2025-06-18

Dias-Souza MV, Haq IU, Pagnin S, et al (2025)

Liposome-encapsulated antibiotics and biosurfactants: an effective strategy to boost biofilm eradication in cooling towers.

Microbial cell factories, 24(1):135.

An excessive amount of water is needed for cooling towers in oil refineries to cool the machinery. However, water has been observed to favor microbial growth and biofilms significantly. The microbial biofilms are usually treated with synthetic biocides, which are ineffective and generate toxic by-products harmful to the environment. This study explores using rhamnolipid and free or encapsulated antimicrobials in liposomes to control several bacterial species exhibiting low antimicrobial susceptibility in planktonic and biofilm forms. The antimicrobial efficacy of rhamnolipid was evaluated through minimum inhibitory concentration (MIC) tests, showing values between 0.244 and 31.25 µg/mL. Biofilm inhibition assays revealed that rhamnolipid significantly reduced biofilm viability, performing comparably to meropenem and more effectively than chloramphenicol. Liposomes were produced with initial diameters of 100 and 200 nm, and encapsulation efficiencies were 56.7% for rhamnolipid, 47.3% for meropenem, and 31.25% for chloramphenicol. Among the formulations, 100 nm rhamnolipid-loaded liposomes exhibited the highest antibiofilm efficacy, achieving up to 92% biofilm reduction in Stenotrophomonas maltophilia 94 (p < 0.01). Meropenem liposomes of 100 nm also performed better than their 200 nm counterparts, with up to 85% reduction in Pseudomonas aeruginosa biofilms (p < 0.05). No significant size-dependent differences were observed for chloramphenicol liposomes, with maximum inhibition around 60% at both sizes. Long-term stability and antibiofilm activity were evaluated exclusively for S. maltophilia 94 over 90 days of refrigerated storage (4 °C). Dynamic light scattering revealed significant vesicle size increases over time for both formulations (p < 0.05), yet their antibiofilm activity remained stable. Rhamnolipid liposomes (100 nm) maintained significantly higher efficacy than 200 nm vesicles throughout the period (p < 0.01). Meropenem liposomes retained considerable activity, though a moderate decrease was noted after 60 days. Scanning electron microscopy (SEM) at days 0 and 90 confirmed the antimicrobial impact of liposomal treatments: biofilms showed disrupted architecture, reduced extracellular matrix, and evident morphological damage to bacterial cells, supporting quantitative results. These findings demonstrate that liposome-encapsulated rhamnolipids and antibiotics are effective against resilient biofilms. The successful formulation and long-term stability of rhamnolipid liposomes highlight their potential as a sustainable and eco-friendly alternative for industrial biofilm control, reducing reliance on conventional biocides and minimizing environmental impact.

RevDate: 2025-06-20
CmpDate: 2025-06-18

Romero M, Luckett J, Dubern JF, et al (2025)

Combinatorial discovery of microtopographical landscapes that resist biofilm formation through quorum sensing mediated autolubrication.

Nature communications, 16(1):5295.

Bio-instructive materials that intrinsically inhibit biofilm formation have significant anti-biofouling potential in industrial and healthcare settings. Since bacterial surface attachment is sensitive to surface topography, we experimentally surveyed 2176 combinatorially generated shapes embossed into polymers using an unbiased screen. This identified microtopographies that, in vitro, reduce colonization by pathogens associated with medical device-related infections by up to 15-fold compared to a flat polymer surface. Machine learning provided design rules, based on generalisable descriptors, for predicting biofilm-resistant microtopographies. On tracking single bacterial cells we observed that the motile behaviour of Pseudomonas aeruginosa is markedly different on anti-attachment microtopographies compared with pro-attachment or flat surfaces. Inactivation of Rhl-dependent quorum sensing in P. aeruginosa through deletion of rhlI or rhlR restored biofilm formation on the anti-attachment topographies due to the loss of rhamnolipid biosurfactant production. Exogenous provision of N-butanoyl-homoserine lactone to the rhlI mutant inhibited biofilm formation, as did genetic complementation of the rhlI, rhlR or rhlA mutants. These data are consistent with confinement-induced anti-adhesive rhamnolipid biosurfactant 'autolubrication'. In a murine foreign body infection model, anti-attachment topographies are refractory to P. aeruginosa colonization. Our findings highlight the potential of simple topographical patterning of implanted medical devices for preventing biofilm associated infections.

RevDate: 2025-06-18

Kim IH, Shin JH, Jeong SB, et al (2025)

Compact and Cost-Effective Autofluorescence Sensor for Real-time Environmental Biofilm Monitoring.

Environmental research pii:S0013-9351(25)01422-7 [Epub ahead of print].

Biofilms, microbial communities embedded in extracellular polymeric substances (EPS), exhibit strong resistance to antimicrobial agents and physical cleaning, making their removal challenging. As persistent sources of contamination, biofilms pose significant challenges in industrial, medical, and environmental sectors. This study presents the development of compact, cost-effective sensor module for real-time biofilm monitoring under ambient light conditions. Using Staphylococcus epidermidis as a model biofilm, autofluorescence properties were analyzed, identifying 285 nm as the optimal excitation wavelength. Five sensor modules were evaluated for sensitivity, linearity, and cost efficiency, leading to the selection of the most suitable photodetector. A prototype was constructed by integrating a 285 nm LED, a photodetector, and a lock-in amplifier (LIA) to minimize environmental light interference. The compact sensor module (90 × 90 × 32 mm) demonstrated stable fluorescence detection under ambient light levels up to 200 lux. This study advances biofilm detection beyond laboratory-based methods, enabling real-time monitoring and management in industrial and everyday environments.

RevDate: 2025-06-18

Tang Y, Chen H, Deng J, et al (2025)

Flagellin deficiency drives multi-drug resistance in Salmonella through biofilm adaptation and efflux pump activation.

Veterinary microbiology, 307:110607 pii:S0378-1135(25)00242-1 [Epub ahead of print].

Salmonella remains a leading foodborne pathogen of global public health concern. Of particular clinical relevance is the monophasic variant of S. Typhimurium, serotyped as S. 4,[5],12:i:-, which has emerged as an increasingly prevalent multi-drug resistance (MDR) strain worldwide. Characterized by the absence of phase 2 flagellar antigen expression, this variant has drawn significant attention due to its association with antimicrobial resistance. In this study, we systematically investigated the impact of flagellin deficiency on antibiotic tolerance in S. Typhimurium and S. Choleraesuis through the construction of isogenic mutants rSC0196 (S. Typhimurium UK-1(ΔfljBΔfliC)) and rSC0199 (S. Choleraesuis C78-3(ΔfljBΔfliC)). Our findings reveal that flagellin gene deletion confers enhanced antibiotic resistance in both serovars, despite significantly impairing their biofilm-forming capacity. Intriguingly, while biofilm biomass was reduced in the mutants, the residual biofilms displayed markedly increased antibiotic tolerance. Further studies demonstrated that flagellin deficiency significantly upregulated efflux pump activity in both mutant strains. These findings provide compelling evidence that flagellin deletion may serve as a key driver of MDR in S. 4,[5],12:i:- clinical isolates, potentially through dual mechanisms involving biofilm phenotypic alterations and efflux pump potentiation. This work not only advances our fundamental understanding of flagellin function in Salmonella pathogenesis but also provides valuable insights for the development of novel antimicrobial strategies targeting flagellin-mediated pathways.

RevDate: 2025-06-18

Anandraj FN, Panda TK, Thangarasu S, et al (2025)

Persulfate salts to combat bacterial resistance in the environment through antibiotic degradation and biofilm disruption.

Water research, 284:123941 pii:S0043-1354(25)00849-8 [Epub ahead of print].

Antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs) have become a critical topic among researchers because of the excessive use of antibiotics in human and animal health care. Globally, it poses a serious threat to human health and the environment. Antibiotics are often poorly metabolized, with 30-90 % excreted into the environment, contaminating aquatic and ground ecosystems, and fostering resistance. Advanced oxidation processes (AOPs), particularly sulfate radical-based AOPs (SR-AOPs), offer promising solutions for degrading antibiotics and resistant biofilms. Persulfate (PS) and Peroxymonosulfate (PMS) are key oxidants in these processes, generating sulfate and hydroxyl radicals when activated by heat, UV light, or transition metals. PS with a redox potential of E°=2.01 V is an affordable and effective oxidant. However, PS requires activation for the degradation of contaminants. PMS is stable across a broad pH range and produces both sulfate and hydroxyl radicals, allowing it to function independently without activation. Thus, PMS serving as a versatile agent for environmental treatment. This review broadly describes the degradation mechanisms of different classes of antibiotics and biofilms. Despite these promising developments, SR-AOPs still face challenges in managing complex wastewater systems, which often contain multiple pollutants. Moreover, gaps remain in understanding of the toxicity of reaction intermediates and in optimizing the large-scale application of these processes. Future research should focus on the in-situ generation of sulfate radicals, combining different activation methods to enhance degradation efficiency, and developing sustainable and cost-effective approaches for large-scale wastewater treatment.

RevDate: 2025-06-20
CmpDate: 2025-06-18

Wang F, Chen S, Zhou J, et al (2025)

ARTP mutagenesis for genome-wide identification of genes important for biofilm regulation in spoilage bacterium Pseudomonas fluorescens PF08.

Applied and environmental microbiology, 91(6):e0021825.

Pseudomonas fluorescens is a vital food spoilage bacterium and commonly spoils foods in the form of biofilms. Yet its biofilm regulation strategies have not been fully revealed. Here, we conducted a genome-wide screen of genes important for biofilm regulation using atmospheric and room temperature plasma mutagenesis together with the whole-genome resequencing technology. Three genes (D7M10_RS02105, D7M10_RS27690, and D7M10_RS25705) encoding GGDEF-EAL domain-containing proteins were found to have different mutation manifestations between biofilm cells and free cells. On direct testing, null mutants of D7M10_RS02105 and especially D7M10_RS27690 exhibited significantly elevated cyclic di-GMP (c-di-GMP) levels. Further studies indicated that a higher level of c-di-GMP caused by the null mutant of D7M10_RS27690 triggered cell growth, the production of siderophore and exopolysaccharide as well as autoaggregation, and hindered cell motility, all of which together promote biofilm formation. RNA-sequencing analysis revealed the transcription profile regulated by D7M10_RS27690, mostly including flagellar assembly and peptidoglycan biosynthesis pathways. Therein, the downregulated genes enriched in flagellar assembly were verified by qRT-PCR; the result of which was in agreement with the decreased cell motility.IMPORTANCEBiofilms formed by spoilage bacterium Pseudomonas fluorescens will bring about food quality and safety issues. In this study, we present the establishment of a genetic method and verified its reliability and efficiency for identifying genes associated with biofilm regulation. The genes we discovered offer new perspectives on the mechanisms of biofilm regulation in spoilage bacterium P. fluorescens. Moreover, the gene screen method based on atmospheric and room temperature plasma mutagenesis and whole-genome resequencing-coupled technology overcomes the labor-intensive issues caused by traditional methods and should generally be suitable for identifying genes associated with biofilm formation or dispersion in other bacteria.

RevDate: 2025-06-18

Yang G, Yang R, Zhu X, et al (2025)

In vitro and in vivo activity of sodium houttuyfonate and sodium new houttuyfonate against Candida auris infection by affecting adhesion, aggregation, and biofilm formation abilities.

Microbiology spectrum [Epub ahead of print].

UNLABELLED: Candida auris is a rapidly spreading multidrug-resistant fungus that causes fatal infections under certain global conditions. Sodium houttuyfonate (SH) and sodium new houttuyfonate (SNH) are stable derivatives of houttuynin (decyl aldehyde) extracted from Houttuynia cordata, both possessing antifungal and antibacterial pharmacological activities. However, the inhibitory effects of SH and SNH on C. auris remain unclear. Therefore, this study aims to evaluate the potential activity and possible mechanisms of SH and SNH as antifungal agents against C. auris. First, our results showed that SH and SNH exhibit significantly inhibitory activity against fluconazole-resistant C. auris strains, but do not possess effective fungicidal activity. In addition, transcriptome and RT-qPCR studies revealed that SH and SNH can repress the expression of genes related to adhesion, aggregation, and biofilm formation. Next, we observed that SH and SNH can disrupt the adhesion and aggregation of early-stage C. auris. Furthermore, using the XTT assay, crystal violet staining, and confocal laser scanning microscopy, we found that the biofilm formation ability of C. auris was disrupted by SH and SNH. We also found that SH and SNH can potentially increase chitin content and expose β-1,3-glucan in the cell wall. Finally, infection models using Galleria mellonella larvae and mice with systemic candidiasis demonstrated that SH and SNH significantly inhibited the colonization and pathological damage of C. auris in vivo. Therefore, our presented results suggest that SH and SNH can effectively inhibit the growth, adhesion, aggregation, and biofilm formation to treat its colonization and pathological damage to the host of C. auris.

IMPORTANCE: Recently, the annual proportion of non-C. albicans infections has been rising. The most notable characteristic of C. auris is its resistance to drugs, including multidrug resistance, which results in treatment failures and poses significant challenges in controlling its spread. Sodium houttuyfonate (SH) and sodium new houttuyfonate (SNH) are effective and stable derivatives of houttuynin (decyl aldehyde) extracted from traditional Chinese herbal medicine Houttuynia cordata, both possessing antifungal and antibacterial pharmacological activities. However, the inhibitory effects of SH and SNH on C. auris remain unclear. Through in vitro and in vivo approaches, we have demonstrated that SH and SNH can effectively inhibit the growth, adhesion, aggregation, and biofilm formation to treat its colonization and pathological damage to the host of C. auris. Thus, our findings provide new insights into possible options for clinical applications in the anti-C. auris.

RevDate: 2025-06-18

Kurbatfinski N, Jurscisek JA, Wilbanks KQ, et al (2025)

Respiratory tract antimicrobial peptides more effectively killed multiple methicillin-resistant Staphylococcus aureus and nontypeable Haemophilus influenzae isolates after disruption from biofilm residence.

Microbiology spectrum [Epub ahead of print].

UNLABELLED: Bacteria newly released (NRel) from biofilm residence via multiple methodologies are commonly significantly more sensitive to antibiotics. We've induced NRel with this phenotype after incubation of biofilms formed by diverse human pathogens with an epitope-targeted monoclonal antibody directed at protective domains within bacterial DNABII proteins that provide structural support to the eDNA-dependent biofilm matrix. The observed heightened sensitivity was due, in part, to increased NRel membrane permeability. In three animal models of human biofilm-mediated infections, this monoclonal induced biofilm disruption with rapid concomitant bacterial clearance and disease resolution in the absence of any co-delivered antibiotic, which suggested a key role of innate immune effectors. Recently, we showed that NRel of the respiratory pathogen nontypeable Haemophilus influenzae (NTHI), as mediated by the DNABII-directed monoclonal, are also highly vulnerable to killing by human polymorphonuclear neutrophils (PMNs). Here, we extended these observations to show that the transient, yet highly vulnerable anti-DNABII NRel phenotype of three isolates of both NTHI and methicillin-resistant Staphylococcus aureus (MRSA) included significant sensitivity to killing by three antimicrobial peptides commonly expressed within the respiratory tract or by PMNs (e.g., human β-defensins 1 and 3 as well as the cathelicidin, LL-37). We envision induction of the NRel phenotype by delivery of this monoclonal antibody to patients with recalcitrant biofilm-mediated diseases to provide greatly improved medical management. Ideally, clearance of NRel will be mediated by innate immune effectors of an immunocompetent host or, if needed, by co-delivered traditional antibiotics, which are canonically ineffective against biofilm-resident bacteria but would be highly effective against NRel.

IMPORTANCE: Pathogenesis of most common chronic and/or recurrent bacterial diseases (e.g., middle ear infections, urinary tract infections, rhinosinusitis, among others) can be attributed to biofilms that are canonically highly resistant to both immune effectors and antibiotics. If we treat biofilms formed by diverse human pathogens with a targeted monoclonal antibody directed at protective domains of bacterial DNA-binding proteins integral to the structural stability of the eDNA-rich biofilm matrix, they are rapidly disrupted with concomitant release of the resident bacteria. These newly released (NRel) bacteria are transiently significantly more sensitive to killing by both traditional antibiotics and human PMNs, and herein, we showed that they are also more readily killed by antimicrobial peptides. Clinically, we hope to leverage this understanding of the NRel phenotype for better medical management of these challenging infections, as well as perhaps even limit or eliminate further contribution to the global antimicrobial resistance 'pandemic'.

RevDate: 2025-06-18

Wan Ahmad Kamil WN, Zainal M, Mokhtar M, et al (2025)

Aggregation and biofilm formation of mono- and co-culture Candida species and Staphylococcus aureus are affected by nutrients in growth media.

Biofouling [Epub ahead of print].

Candida species and Staphylococcus aureus coexist in nosocomial infections. These interkingdom interactions are associated with oral biofilm formation, leading to various oral diseases. This study elucidated the interkingdom interactions of these microorganisms, particularly their aggregation and biofilm formation, in three different media. Candida auris, Candida albicans, Candida lusitaniae, Candida dubliniensis, Candida parapsilosis, Candida glabrata and S. aureus were used in this study. Aggregation assays were conducted to determine planktonic interaction, and biofilm assays were performed to investigate intra- and interkingdom interactions in a static biofilm environment. Most Candida spp. exhibited a high auto-aggregation percentage in brain heart infusion broth supplemented with yeast extract (BHIYE). In addition, co-culture biofilm with S. aureus significantly reduced the total cell counts of Candida spp. compared to mono-culture (p < 0.05). In conclusion, co-aggregation, biofilm biomass and total cell count were species- and growth medium-dependent, and S. aureus interacted antagonistically with Candida spp.

RevDate: 2025-06-17

Yang J, Zhang L, Sun H, et al (2025)

Synergistic membrane-biofilm-sludge system coupling partial nitritation and anammox: achieving efficient nitrogen removal in high-ammonia/low-carbon condensate wastewater.

Bioresource technology pii:S0960-8524(25)00785-0 [Epub ahead of print].

Condensed wastewater treatment faces challenges from elevated ammonia-nitrogen levels (1972-2365 mg/L), a low carbon-to-nitrogen ratio (0.02-0.03), and inhibitory sulfides. To overcome these, a novel hybrid system integrating an effluent membrane-enhanced fixed-biofilm activated sludge (IFAS) reactor with partial nitritation/anammox (PN/A) was developed. The system demonstrated exceptional nitrogen removal performance at a maximum nitrogen removal rate of 1.5 kg N/(m[3]·d) with a nitrogen removal efficiency of 82.3 %. Denitrification enhanced advanced nitrogen removal with a low nitrate production ratio (4.5 %), minimizing secondary pollution risks. Microbial analysis revealed substantial enrichment of anaerobic ammonium-oxidizing bacteria, with Candidatus Brocadia dominating the biofilm community (24.3 %). Membrane-mediated biomass retention selectively enriched Nitrosomonas (10.1 %) in suspended sludge, while biofilm detachment promoted granular anammox biomass development and further elevated Candidatus Brocadia abundance by 4.8 %. This synergistic configuration enhances process stability for treating high-ammonia/low-carbon wastewater and promotes the practical implementation of IFAS-PN/A systems.

RevDate: 2025-06-17

Pan Y, Liu H, Liu Y, et al (2025)

Antimicrobial peptide-antibiotic synergy exerts anti-streptococcus suis infection by membrane disruption, ROS induction and biofilm inhibition.

International immunopharmacology, 161:115053 pii:S1567-5769(25)01043-4 [Epub ahead of print].

With the increasing emergence of antimicrobial resistance, the rise of multidrug-resistant Streptococcus suis (S. suis) has caused a great threat on global public health. The combination of antimicrobial peptide (AMP) and antibiotics is an efficient strategy to enhance antibacterial efficacy and combat bacterial antibiotic resistance. In this study, the antibacterial efficacy of chicken-derived AMP CATH-1 combined with tetracycline against S. suis infection was investigated in vitro and in vivo. The results showed that combination of CATH-1 and tetracycline exerted effectively anti-S. suis activity, which rapidly killed all tested bacteria in 60 min. In the mice infection model, CATH-1 combined with tetracycline improved survival rate of SC19-infected mice, reduced bacterial load in different tissues and alleviated the inflammatory response as well as inflammatory damage. Furthermore, CATH-1 reduced the emergence of bacterial resistance to tetracycline. Mechanically, CATH-1 disrupted cell membrane via SEM observation and SYTO9/PI staining. CATH-1 in combination with tetracycline aggravated reactive oxygen species (ROS) accumulation and proton motive force (PMF) disruption compared to CATH-1 or tetracycline alone. In addition, CATH-1 inhibited efflux pump function. Importantly, we identified a critical gene steAB associated with biofilm formation and CATH-1 alone or in combination with tetracycline inhibited biofilm formation. Our study shows effective anti-S. suis infection of CATH-1-tetracycline synergy, which provides the basis on the development of AMP as additives to antibiotics.

RevDate: 2025-06-17
CmpDate: 2025-06-17

Wang Y, Sun C, Cai L, et al (2025)

Osmotic and pH Stress-Responsive Two-Component System, OmpR/EnvZ, Modulates Type III Secretion, Biofilm Formation, Swimming Motility and Virulence in Acidovorax citrulli xjL12.

Molecular plant pathology, 26(6):e70107.

Acidovorax citrulli, the causal pathogen of bacterial fruit blotch of cucurbits, relies on a functional type III secretion system (T3SS) for pathogenicity. Two-component systems (TCSs) are primary signal transduction mechanisms for bacteria to detect and adapt to various environmental conditions. However, the role of TCS on regulating T3SS and other virulence factors in response to environmental stimuli is still poorly understood in A. citrulli. Here, we report the identification of a conserved TCS, OmpR/EnvZ, involved in hypersensitive response (HR) induction in Nicotiana benthamiana by screening a transposon-insertion library in the group II strain xjL12 of A. citrulli. Transcription analysis confirmed that OmpRAc/EnvZAc was upregulated in response to elevated osmotic pressure, low and high pH conditions, and host environment. Deletions of envZAc, ompRAc, or both envZAc and ompRAc in A. citrulli attenuated virulence to melon seedlings and mature leaf tissues, and delayed HR in N. benthamiana. OmpRAc was activated by EnvZAc and directly bound to the promoter region of hrpG, a major regulator of T3SS. This binding activated hrpG transcription and promoted T3SS assembly in T3SS-inducing medium, XVM2. Additionally, the OmpRAc/EnvZAc mutants of A. citrulli displayed reduced swimming motility due to impaired flagella formation, but also had enhanced biofilm formation and exopolysaccharide production. OmpRAc/EnvZAc regulation of these virulence factors in A. citrulli depended on its own conserved phosphorylation sites. This work illuminates a signalling pathway for regulating the T3SS and provides insights into the OmpR/EnvZ-mediated virulence regulatory network in A. citrulli.

RevDate: 2025-06-16

Yang Y, Chen N, Fan J, et al (2025)

Spatiotemporal Immunomodulation of Macrophages via NLRP3/IL-1β Pathway by Core-Shell Microneedles to Promote Healing of Biofilm-Infected Diabetic Ulcers.

Small (Weinheim an der Bergstrasse, Germany) [Epub ahead of print].

Macrophage phenotypic dysregulation, spatially by biofilm and dynamically in time, impedes the healing of diabetic ulcers (DUs). Effective treatment requires enabling spatiotemporal regulation of macrophage polarization, balancing the M1 pro-inflammatory antimicrobial response with the M2 anti-inflammatory tissue-regeneration response. Here, a core-shell microneedle system (LM-MG@MN) is proposed with spatiotemporal immunomodulation features, designed to spatially disrupt biofilm barriers and sequentially induce macrophage polarization from M0 to M1 and subsequently to M2 by regulating the NLRP3/IL-1β pathway. Glucose oxidase (GOX)-loaded 2D MXene nanosheets (MG) are encapsulated in a hyaluronic acid-β-cyclodextrin (HA-β-CD) matrix as the MN shell layer. The rapid dissolution of this shell triggers MG to induce pro-inflammatory polarization of macrophages from M0 to M1, aiding in clearing biofilm infections. Liposomes (LM) carrying the NLRP3 inflammasome inhibitor MCC950 are embedded within a methacrylate hyaluronic acid (HAMA) matrix in the MN core. In the later stages of wound healing, LM is released gradually from the core, promoting the anti-inflammatory polarization of macrophages from M1 to M2 and accelerating tissue regeneration by enhancing crosstalk with fibroblasts and endothelial cells. Additionally, RNA sequencing indicates that LM-MG@MN regulates macrophage metabolic reprogramming to enhance DUs healing. This spatiotemporal immunomodulation strategy offers a promising approach for clinical DUs treatment.

RevDate: 2025-06-16

Crippa BL, Valente PLM, Barros ELP, et al (2025)

Investigation of biofilm-associated genes and biofilm formation in Non-aureus Staphylococcus (NAS) isolated from cow's milk.

Biofouling [Epub ahead of print].

The isolation of non-aureus Staphylococcus (NAS) from the milk of both healthy cows and cows with mastitis has been frequently reported. However, there are few in-depth studies regarding their virulence profile and the ability of these microorganisms to form biofilms. Therefore, this research aimed to evaluate the biofilm formation capacity of NAS isolates from Brazilian milk. In this work, 309 NAS isolates were subjected to the Congo Red Agar (CRA) phenotypic test. Next, genotypic characterization was carried out by screening the bap, icaA, icaD, and MSCRAMMs genes: bbp, cna, ebps, eno, fib, fnbA, fnbB, clfA and clfB. Finally, ten isolates that presented the highest frequency of the genes analysed were selected to evaluate their ability to form biofilm on stainless-steel discs. t The number of cells (log10 CFU/cm[2]) in the biofilms was assessed at three time periods (24 h, 48 h, and 72 h) at a temperature of 25 °C. 35 NAS (11.32%) produced biofilms in the CRA test. Genotypic analysis showed the eno (38.5%) and bap (27.5%) genes were the most prevalent. In the analysis of biofilm formation on stainless steel, the factor 'growth time' had no significant effect on cell numbers. All selected isolates formed biofilm on stainless steel, and cell numbers were estimated to be in the 5.94 to 9.10 log10 CFU/m[2] range. These results provide evidence that NAS isolated from milk may represent a risk to human and animal health since they carry several virulence genes and demonstrate the ability to form biofilms.

RevDate: 2025-06-17

Tareau AS, Tahrioui A, Gonzalez M, et al (2025)

Squalamine and claramine A1 disperse Pseudomonas aeruginosa biofilm.

Biofilm, 9:100293.

Pseudomonas aeruginosa is an opportunistic pathogen that causes both acute and chronic infections, including pneumonia, bloodstream infections, urinary tract infections, and surgical site infections. It poses a significant threat to individuals with chronic lung conditions, particularly those with cystic fibrosis. Squalamine and claramine A1 have emerged as promising antibacterial compounds, exhibiting activity against a broad range of both Gram-positive and Gram-negative bacteria. Beyond their potent antibacterial properties, our findings reveal that sub-inhibitory concentrations of claramine A1 and squalamine can disperse pre-formed P. aeruginosa biofilm without impacting bacterial growth. While claramine A1, but not squalamine, enhances membrane fluidity, the structural difference between these compounds lies primarily in their spermine and spermidine moieties. Notably, we found that spermine, unlike spermidine, was able to both disperse biofilm and increase membrane fluidity. Together, our results suggest that while both compounds are effective at disrupting P. aeruginosa biofilm, they likely act through distinct mechanisms.

RevDate: 2025-06-17

Kuik C, de Boer C, van Hoogstraten SWG, et al (2025)

Proteomic signatures of Staphylococcus aureus biofilm maturation on orthopaedic implants.

Biofilm, 9:100287.

Implant-associated infections pose a significant clinical challenge in the orthopaedic field, often leading to implant failure and revision surgeries. These infections are hard to treat, particularly due to the formation of bacterial biofilms. Orthopaedic implant surfaces feature varying roughness and compositions to optimise implant osseointegration and performance. Highly polished surfaces are used in articulating areas of high shear force to minimise wear particle formation, while rough or porous surfaces enhance implant and bone fixation. However, increased surface roughness or porosity can also promote bacterial adhesion and biofilm formation, potentially elevating the risk of chronic infections. In this study, an automated single-pot solid-phase enhanced sample preparation protocol (SP3) workflow was developed to investigate the differences in proteomic response of immature and mature S. aureus biofilms on titanium (Ti) surfaces with varying roughness (polished, corundum-blasted), and a plasma-sprayed microporous calcium phosphate coated surface (plasmapore), representing clinically relevant orthopaedic implants. Mature biofilms showed increased proteins related to toxin activity and the tricarboxylic acid (TCA) cycle, while immature biofilms had elevated proteins tied to binding, catalytic activities, and metabolism, suggesting surface topography influences early biofilm formation. This study highlights potential protein targets for novel antimicrobial therapies and suggests testing these as coatings on Ti surfaces, with the proteomics platform serving as a tool to evaluate bacterial and host responses.

RevDate: 2025-06-15

Souza CM, Paulo EA, Souza NAA, et al (2025)

Enhanced biofilm formation by Candida tropicalis morphotypes under host-mimicking conditions: Insights into cell wall modifications and gene expression.

Microbial pathogenesis pii:S0882-4010(25)00532-7 [Epub ahead of print].

BACKGROUND AND OBJECTIVE: Candida tropicalis is an important fungal pathogen capable of colonizing diverse host niches. This study investigates how phenotypic switching influences biofilm formation by C. tropicalis under host-mimicking conditions, including simulative vaginal secretions (VS) and artificial urine (AU).

METHODS: Our study analyzed three morphotypes derived from the 49.07 switching system: a clinical strain (parental) and two phenotypic switching morphotypes, rough variant and rough revertant (RR). Biofilm formation on polystyrene was assessed under different culture conditions (AU, VS, and RPMI-1640). Biofilm characteristics, including filamentation, cell surface hydrophobicity, and cell wall composition (β-glucan, chitin, and mannan), were investigated. Additionally, the expression levels of Agglutinin-like sequence genes (CtrALS1, CtrALS3) and the EFG1 gene (Enhanced filamentous growth protein 1) was quantified using RT-qPCR.

RESULTS: Phenotypic switching morphotypes of C. tropicalis produced significantly more biofilm under host-like conditions compared to the parental strain. Increased filamentation in the rough variant and revertant correlated with biofilm biomass across all conditions. Switched morphotypes also exhibited higher cell surface hydrophobicity and altered cell wall composition, with increased β-glucan and variable chitin content under host-mimicking conditions. The RR morphotype showed higher expression of CtrALS3 and EFG1 compared to the parental strain in AU and VS.

CONCLUSIONS: Phenotypic switching influences important biofilm traits-hydrophobicity, filamentation, cell wall composition, and gene expression-in host-mimicking environments. These findings highlight the role of phenotypic switching in C. tropicalis adaptation to host niches, particularly vaginal fluids and urine.

RevDate: 2025-06-17
CmpDate: 2025-06-14

Lehmusvaara S, Sillanpää A, Wouters M, et al (2025)

M.marinum lacking epsH shows increased biofilm formation in vitro and boosted antibiotic tolerance in zebrafish.

NPJ biofilms and microbiomes, 11(1):109.

Recent discoveries have indicated that biofilm communities may play a role in natural drug tolerance of Mycobacterium tuberculosis. A transposon-based mutation library of a closely related species, Mycobacterium marinum, was used to identify clones in which the relative amount of extracellular DNA (eDNA), an important component of the extracellular matrix of biofilms, is altered. The disruption of a putative glycosyl transferase gene QDR78 11175, epsH, caused a substantial increase of the eDNA content of biofilms, and increased the growth rate and the biomass/cell in biofilm-forming conditions compared to wild-type. The increased abundance of biomass was mainly due to the elevated levels of eDNA and proteins in the extracellular matrix. The growth of the ΔepsH strain in the zebrafish was normal, but the mutant developed greater antibiotic tolerance in the adult zebrafish model. These results suggest that the extracellular matrix of biofilms increases antibiotic tolerance of mycobacteria during infection.

RevDate: 2025-06-14

Ju X, Sun H, Ruan C, et al (2025)

Prophage induction and quorum sensing enhance biofilm stability and resistance under ammonia-oxidizing bacteria-mediated oxidative stress.

Water research, 284:124010 pii:S0043-1354(25)00918-2 [Epub ahead of print].

Ammonia-oxidizing bacteria (AOB) and prophage-carrying bacteria are prevalent in water treatment and reuse systems, yet their interactions and implications for biofilm formation and microbial risks remain insufficiently understood. Here, we demonstrate that oxidative stress arising from the metabolism of the AOB Nitrosomonas europaea induces prophage activation in lysogenized Escherichia coli (λ+). This activation triggers cellular lysis, leading to the release of intracellular components (e.g., protein and DNA) and upregulated quorum sensing (QS) followed by biosynthesis and excretion of extracellular polymeric substance (EPS). Integrated transcriptomic and proteomic analysis revealed that the presence of N. europaea significantly upregulated QS- and EPS-related genes by 2.14-2.93 and 2.81-3.11 folds in E. coli (λ+), respectively. Surviving E. coli (λ+) exhibited enhanced prophage-bacterium symbiosis and activated toxin-antitoxin systems, enhancing their resilience to environmental stress. These microbial adaptations markedly increased EPS production, fostering biofilm development and conferring enhanced biofilm resilience to disinfectants and bacterial antibiotic tolerance. Furthermore, metagenomic analysis at the microbial community wide level demonstrated that ammonia addition-driven AOB enrichment stimulated multi-species biofilm formation, promoted bacterium-phage interactions, and increased bacterial antibiotic resistance. Overall, our findings reveal that oxidative stress driven by AOB accelerates biofilm development, an overlooked phenomenon with potential to exacerbate microbial risks.

RevDate: 2025-06-17
CmpDate: 2025-06-13

Kamwouo T, Bouttier S, Domenichini S, et al (2025)

Extracellular DNA filaments associated with surface polysaccharide II give Clostridioides difficile biofilm matrix a network-like structure.

NPJ biofilms and microbiomes, 11(1):108.

Clostridioides difficile is an anaerobic, spore-forming, Gram-positive bacterium, and a leading cause of healthcare-associated intestinal infections. Recurrences occur frequently, most of them being relapses. Apart from spores, C. difficile biofilm is hypothesized as a reservoir for relapses. Thus, increased knowledge on in vitro biofilm formation and characteristics is required. We finely characterized the matrix components in 4 C. difficile strains. Confocal microscopy revealed for the first time the presence of eDNA filaments connecting bacteria, with a spider's web-like organization. Biofilm disruption with DNase I suggests that eDNA, even in low abundance, plays a key role in the biofilm scaffold, maintaining biofilm cohesion by connecting bacteria. Observation of strong overlapping staining, particularly in the highest biofilm-producing strain tested between eDNA and polysaccharide II or lipoprotein CD1687, suggests that interactions between these components may enhance biofilm cohesion. Whereas autolysis does not appear to be a major way of matrix component release under our conditions, eDNA was sometimes associated with lipidic round shapes that can evoke vesicle structures. Together, these results suggest that the bacterial aggregation and structuring of the C. difficile biofilm involve several components of the matrix, including eDNA, interacting with each other to build the scaffold of biofilm.

RevDate: 2025-06-13

P AT, Jayakumar J, Vinod V, et al (2025)

Anti-Biofilm Activity of Lysostaphin-Functionalized Titanium Surfaces Against Staphylococcus aureus.

Microbial pathogenesis pii:S0882-4010(25)00525-X [Epub ahead of print].

Staphylococcus aureus has the ability to adhere to implant surfaces and form biofilms, which are highly resistant to standard antimicrobial treatments. These biofilm infections pose significant risks, particularly for patients with medical implants. This study investigates the covalent attachment of lysostaphin (Lst) to titanium (Ti) surface (Lst-Ti) and it's antibiofilm activities. Lst-Ti surfaces were characterized using energy-dispersive X-ray spectroscopy (SEM-EDS) confirming successful protein attachment. Biocompatibility was assessed through cell viability tests, revealing minimal hemolytic activity and excellent cytocompatibility. Antimicrobial assays demonstrated that Lst-Ti inhibited S. aureus growth and disrupted established biofilms, including those formed by methicillin-resistant S. aureus (MRSA). Scanning electron microscopy further validated the reduction in biofilm formation on the modified surfaces. These results suggest that Lst-Ti surfaces offer a promising strategy for preventing and treating implant-associated biofilm infections. Unlike antibiotic-loaded surfaces, Lst-Ti provides long-term antimicrobial protection without any release Lst protein, reducing the risk of antibiotic resistance and systemic absorption. This approach could enhance patient outcomes by reducing the need for implant removal in infection cases. Future in vivo studies will be necessary to confirm the clinical applicability of this approach.

RevDate: 2025-06-13

Zhang Y, Lin Y, Zhang J, et al (2025)

Diversity of optrA Genetic Structures in Enterococcus faecalis from Retail Chicken and the Differential Biofilm-Forming Abilities of Isolates at Non-Frozen Temperatures.

Journal of applied microbiology pii:8161686 [Epub ahead of print].

AIMS: This study aimed to explore the diversity of optrA genetic structures in Enterococcus faecalis from retail chicken and the variance in their biofilm-forming capabilities at refrigerated and room temperatures. By comprehensively studying these two traits, we aim to fully understand the transmission and biofilm-forming capabilities at non-frozen temperatures of optrA-positive E. faecalis.

METHODS AND RESULTS: Analysis of Chinese-sourced E. faecalis genomes in the database indicated that 65.76% were optrA-positive, with animals as the predominant hosts. In 2020, 15 optrA-carrying strains were isolated from 96 retail chicken samples from four Chinese supermarkets. The optrA gene was situated on plasmids or chromosomes. A novel optrA-carrying plasmid structure was identified, resulting from IS1485-mediated structural changes. Tn6674-like and Tn558-like structures mediated inter-chromosomal transfer of optrA, while IS1216E and ISEnfa1 promoted inter-plasmid transfer. Some isolates showed a greater tendency for biofilm formation at refrigerated temperature, and others at room temperature.

CONCLUSIONS: In conclusion, this research reveals the genetic intricacy of optrA-positive E. faecalis and their temperature-associated biofilm-forming behaviors, highlighting the necessity of monitoring food-related microbial hazards.

RevDate: 2025-06-15

Yilmaz Topcam MM, Prayoonwiwat N, Bruschi C, et al (2025)

Exogenous L-Cysteine and Its Transport Through CtaP Play a Role in Biofilm Formation, Swimming Motility, and Swarming Motility of Listeria monocytogenes.

Foods (Basel, Switzerland), 14(11):.

Listeria monocytogenes is of a significant concern for the food industry, largely due to its ability to form biofilms. Flagellar motility and environmental factors are crucial for biofilm formation. Cysteine is an important compound affecting the behavior of this bacterium; therefore, we investigated its role in growth, biofilm formation and motility of L. monocytogenes 10403S through a mutant in cysteine uptake (ΔctaP). Basal defined media (DM) and L-cysteine-supplemented DM were used. Biofilm formation was promoted by L-cysteine supplementation in both wild type (WT) and ΔctaP. Lower biofilm formation of ΔctaP compared to WT indicates the significance of the cysteine transporter and cysteine uptake. A negative correlation was found between growth and biofilm formation, especially in the presence of high L-cysteine concentrations. Motility experiments showed that as the L-cysteine concentration increased, the swarming motility of WT decreased. Furthermore, swimming motility of WT was enhanced with L-cysteine supplementation, while the swimming motility of ΔctaP remained unaffected. To evaluate the role of cysteine and CtaP in biofilm formation and motility, transcriptome analysis, comparing WT and ΔctaP in basal and L-cysteine-supplemented (1.57 and 3.67 mM) DM, was conducted at 37 °C. The investigation of biofilm-related genes explained the role of ctaP and revealed induced expression of flagella and chemotaxis genes by L-cysteine.

RevDate: 2025-06-15

Florit-Ruiz A, Rago L, Rojas A, et al (2025)

Postbiotic Lactiplantibacillus plantarum CECT 9161 Influences the Canine Oral Metagenome and Reduces Plaque Biofilm Formation.

Animals : an open access journal from MDPI, 15(11):.

Periodontal diseases are highly prevalent in dogs and intricately interconnected with the composition and functional attributes of the oral microbiota. The demand for non-invasive interventions to support oral health presents an opportunity for functional ingredients. The novel postbiotic heat-treated (HT) Lactiplantibacillus plantarum CECT 9161 inhibited growth and biofilm formation of oral microorganisms in vitro. The in vitro growth of saliva-derived biofilms was also inhibited and revealed microbiome modulation. Two doses of the postbiotic (LOW: 5 mg dog/day, HIGH: 25 mg/dog/day) were assessed in a placebo-controlled, double-blinded, 57-day clinical trial involving 60 dogs. Associations were found between the postbiotic, reduced plaque formation, and modulation of the oral microbiome, including increased abundance of genes involved in denitrification, heme and catechol biosynthesis, and oxidative stress reduction. The results suggest that HT Lactiplantibacillus plantarum CECT 9161 may support oral health in dogs by modifying the microbiome of supragingival plaque and reducing plaque formation.

RevDate: 2025-06-15
CmpDate: 2025-06-13

Lin LC, Tsai YC, NT Lin (2025)

Phage-Antibiotic Synergy Enhances Biofilm Eradication and Survival in a Zebrafish Model of Pseudomonas aeruginosa Infection.

International journal of molecular sciences, 26(11):.

Pseudomonas aeruginosa is a gram-negative opportunistic pathogen that poses a significant threat due to its increasing multidrug resistance, particularly in clinical settings. This study aimed to isolate and characterize a novel bacteriophage, phiLCL12, from hospital wastewater and evaluate its potential in combination with antibiotics to combat P. aeruginosa infections and biofilm formation. Transmission electron microscopy revealed that phiLCL12 possesses a long contractile tail. The isolated phage exhibited a broad host range of 82.22% and could adsorb up to 98% of its target within 4 min. It was effective against multidrug-resistant strains at both high and low multiplicities of infection (MOIs) levels in lysis tests. Taxonomic classification was determined using PhaGCN2 and Whole genomic analysis, and the results identified phiLCL12 as a member of the Pbunavirus. In vitro experiments demonstrated that phiLCL12 significantly enhanced biofilm clearance and inhibited biofilm formation when combined with sub-inhibitory concentrations of imipenem. Furthermore, in vivo experiments using a zebrafish model showed that phage-antibiotic synergy (PAS) improved survival rate compared to antibiotic treatment alone. This study demonstrates that phiLCL12 is effective in both eradicating and preventing P. aeruginosa biofilm formation. The combination of phiLCL12 and imipenem provides a synergistic effect, significantly enhancing survival outcomes in a zebrafish model. These findings highlight the potential of phage-antibiotic synergy as a promising therapeutic strategy against biofilm-associated infections.

RevDate: 2025-06-15
CmpDate: 2025-06-13

Górecka H, Guźniczak M, Buzalewicz I, et al (2025)

Alpha-Mangostin: A Review of Current Research on Its Potential as a Novel Antimicrobial and Anti-Biofilm Agent.

International journal of molecular sciences, 26(11):.

Alpha-mangostin (α-MG) is a prenylated xanthone extracted from the pericarp of the mangosteen tree (Garcinia mangostana) fruit. The compound exhibits a broad range of therapeutic properties, such as anti-inflammatory, antioxidative, and antimicrobial activity. This review highlights new findings in antibacterial studies involving α-MG, demonstrates its potent activity against Gram-positive bacteria, including Staphylococcus and Enterococcus genera, and describes the antibacterial mechanisms involved. Most cited literature comes from 2020 to 2025, highlighting the topic's relevance despite limited new publications in this period. The primary antibacterial mechanism of α-MG consists of the disruption of the bacterial membrane and increased bacterial wall permeability, leading to drug accumulation and cell lysis. Other mechanisms include genomic interference and enzyme activity inhibition, which impair metabolic pathways. α-MG can also disrupt biofilm formation, facilitate its removal, and prevent its maturation. Furthermore, α-MG presents strong synergistic action with common antibiotics and other phytochemicals, even against drug-resistant strains, facilitating infection treatment and allowing for reduced drug dosage. The main challenge in developing α-MG-based drugs is their low aqueous solubility; therefore, nanoformulations have been explored to improve its bioavailability and antibacterial stability. Extended research in this direction may enable the development of effective antibacterial and anti-biofilm therapies based on α-MG.

RevDate: 2025-06-12

Ruan Y, Li R, Zheng P, et al (2025)

AD1 Aptamer-Engineered Fluconazole-Loaded PLGA-PEG Nanoformulations Potentiate Antifungal Efficacy through Biofilm-Penetrating Targeting against Candida albicans.

ACS applied bio materials [Epub ahead of print].

In this work, aptamer AD1-modified poly(lactic-co-glycolic acid)-poly(ethylene glycol)-fluconazole nanoparticles (AD1-PLGA-PEG-FLUCZ) were prepared, enabling the antifungal drug FLUCZ to specifically target the biofilm of Candida albicans, prolonging its action time on the biofilm, and enhancing its killing effect. The analytical results demonstrated that the AD1-PLGA-PEG-FLUCZ nanoparticulate system achieved a FLUCZ loading capacity of 5.89 ± 0.07% with an encapsulation efficiency of 84.51 ± 0.18%. Physicochemical characterization revealed a uniform particle size distribution (390 nm) and stable surface charge (-30.45 mV). Furthermore, the formulation exhibited minimal hemolytic activity and low cytotoxicity in biocompatibility assessments. AD1-PLGA-PEG-FLUCZ adheres to the cell surface of C. albicans, causing severe cellular damage and collapse, prolonging its lag phase and shortening the logarithmic growth phase. AD1-PLGA-PEG-FLUCZ demonstrates significant inhibitory effects on C. albicans biofilms, with this inhibitory activity being concentration-dependent. AD1-PLGA-PEG-FLUCZ-treated mice infected with C. albicans biofilms demonstrated accelerated body weight recovery and near-normalization of the serum Mouse C-Reactive Protein levels. Concurrently, comparatively lower serum concentrations of ALT and AST were observed in the AD1-PLGA-PEG-FLUCZ treatment group, indicating minimized hepatocellular injury. H&E staining results revealed no detectable damage in the heart, liver, spleen, lung, and kidney tissues of mice treated with AD1-PLGA-PEG-FLUCZ. Furthermore, while C. albicans infection induced significant pulmonary pathology, the treated group exhibited near-complete restoration of lung tissue histology. Analysis using an in vivo imaging system in mice demonstrated that AD1-PLGA-PEG-FLUCZ exhibited significant accumulation in both the hip-infected area and lung tissue, indicating its pronounced targeting effect against C. albicans. In conclusion, AD1-PLGA-PEG-FLUCZ exhibits a targeted anti-C. albicans effect and holds promise as an agent for combating C. albicans.

RevDate: 2025-06-12

ElKenawy RH, Zaki MES, Essa SG, et al (2025)

Molecular study of candiduria in pediatric patients in in relation to biofilm formation and fluconazole tolerance.

Diagnostic microbiology and infectious disease, 113(2):116943 pii:S0732-8893(25)00266-4 [Epub ahead of print].

BACKGROUND: There are limited studies about the presence of Candida species (Candida spp.) and ABC genotypes in hospital acquired urinary tract infection (UTI) in children.

AIM: the study aimed at identification of Candida spp. associated with candiduria in children, detection of fluconazole tolerance and biofilm formation and genotyping of C. albicans.

METHOD: The study was conducted on pediatric patients with hospital-acquired UTI. A urine sample was cultured on the agar CHROM Candida. Molecular identification of Candida spp. was performed by nested polymerase chain reaction (PCR) and specific genotyping of C. albicans was performed by PCR. Biofilm production and fluconazole tolerance were tested for the isolates.

RESULTS: 97 children were included. Urinary catheters were inserted reported in 69.1 % of the children and previous antibiotic intake was reported in 34 % of them. The identified species were C. albicans (66 %) followed by Nakaseomyces glabrata (19.6 %), Candida tropicalis (11.3 %) and Candida kruzei (3.1 %). The ability of biofilm formation was 100 %. The Pichia kudriavzevii had a highest significant rate of fluconazole tolerance (66.7%), (P=0.045). Resistance to fluconazole was observed significantly with C. tropicalis (63.6%), (P=0.033). The common genotypes of C. albicans were A (60.9%) and C (39.1%). There was significant capacity of C. albicans genotype C to form strong biofilm (P<0.001).

CONCLUSION: The study found that C. albicans remains the most prevalent species in candiduria. The ability of Candida spp. to form biofilms was 100% among the isolates. Strong biofilm formation being significantly associated with increased fluconazole resistance and C. albicans genotype C.

RevDate: 2025-06-12

Zhao L, Zhang H, Zha L, et al (2025)

Bactericidal and anti-biofilm activity of ebastine against Staphylococcus aureus.

Letters in applied microbiology pii:8161046 [Epub ahead of print].

Drug repurposing, offers promising opportunities to address infections caused by multidrug-resistant bacteria. This study was to evaluate the bactericidal activity, anti-biofilm properties, and potential mechanisms of the antihistamine drug ebastine against S. aureus. The minimum inhibitory concentrations of ebastine against standard and clinical S. aureus isolates were determined using the broth microdilution method. The MIC values ranged from 2 to 8 µg·mL-1, indicating good activity against clinical drug-resistant strains. Time-kill curve analyses revealed a dose-dependent bactericidal effect. Regarding anti-biofilm activity, ebastine significantly inhibited biofilm formation at higher concentrations and demonstrated a moderate ability to eradicate preformed biofilms. Mechanistic studies revealed that ebastine exerted the antimicrobial effects by causing disruption to bacterial membrane integrity and inducing reactive oxygen species generation. Furthermore, safety evaluations showed that ebastine exhibited limited toxicity to mammalian cells, with negligible hemolytic effects and good overall safety profiles. This study provided new insights into the potential applications of ebastine in the field of antimicrobial therapy, highlighting its promise as a non-traditional antibacterial agent.

RevDate: 2025-06-13

Badge AK, Sharma I, Bankar NJ, et al (2025)

Integration of three-dimensional multicolor holography with microfluidic three-dimensional biofilm-on-a-chip technology for advancing the treatment of diabetic foot ulcers: An innovation in phage therapy.

Journal of research in medical sciences : the official journal of Isfahan University of Medical Sciences, 30:27.

RevDate: 2025-06-12

Matela AM, Siatkowski CW, Yan C, et al (2025)

Student-led experimental evolution reveals novel biofilm regulatory networks underlying adaptations to multiple niches.

bioRxiv : the preprint server for biology pii:2025.06.06.658356.

UNLABELLED: We established a research-education partnership known as EvolvingSTEM that provides secondary school students the opportunity to conduct authentic research experiments centered on microbial evolution. These experiments are currently conducted by thousands of high school students and can offer an unprecedented window into biofilm adaptation while building a community of young researchers. Providing high school students access to research experiences improves learning and can have positive and long-lasting impacts on their attitudes towards science. Moreover, student research can make impactful scientific contributions. Through EvolvingSTEM, students evolve populations of Pseudomonas fluorescens in a biofilm bead model and observe heritable changes in colony morphology. Genome sequencing of 70 mutants that they picked identified parallel mutations in genes known to regulate biofilm growth (wsp , yfiBNR , morA, fuzY). We also uncovered novel adaptations: loss-of-function mutations in phosphodiesterase PFLU0185 that did not alter colony morphology, and mutations affecting periplasmic disulfide bond formation producing small colonies. PFLU0185 mutations consistently reached high frequencies and phenotyping revealed roles in cyclic di-GMP regulation, biofilm formation, and motility, prompting us to name this gene bmo (b iofilm and mo tility o ptimizer). Competition experiments and microscopy demonstrated bmo mutants employ generalist strategies and coexist with the ancestor and specialist mutants through niche differentiation. Consequently, phenotypic diversity is maintained, with smooth (ancestral and bmo) colonies consistently outnumbering wrinkly and fuzzy variants. The study advances understanding of biofilm genetic architecture while demonstrating that student-led research can uncover mechanisms of microbial adaptation relevant to Pseudomonas infection biology and provide transformative STEM experiences.

IMPORTANCE: Bacterial biofilms dominate microbial life, yet their evolutionary genetics remain incompletely understood. This science education project engages thousands of high school students in experimental evolution, yielding discoveries about biofilm adaptation while transforming their science education. Selected mutants included PFLU0185/ bmo , a conserved phosphodiesterase that helps bacteria balance the competing demands of attachment and dispersal essential for biofilm life cycle success. The finding that smooth-colony generalists rather than conspicuous variants dominate biofilm adaptation adds to our understanding of the process of niche differentiation in biofilms. This work also demonstrates the power of distributed research networks for discovery of new genetic pathways of adaptation. Students gained authentic research experience, potentially inspiring them to join the next generation of scientists, while identifying mutants adapted to discrete conditions that maintain diversity within biofilms. This synergy between education and discovery offers a scalable model for addressing complex biological questions while developing scientific literacy in diverse classrooms.

RevDate: 2025-06-12

Sarkar S, Barnaby R, Nymon A, et al (2025)

Let-7b-5p loaded Mesenchymal Stromal Cell Extracellular Vesicles reduce Pseudomonas - biofilm formation and inflammation in CF Bronchial Epithelial Cells.

bioRxiv : the preprint server for biology pii:2025.05.28.656674.

UNLABELLED: Cystic Fibrosis (CF) is a multiorgan disease caused by mutations in the CFTR gene, leading to chronic pulmonary infections and hyperinflammation. Among pathogens colonizing the CF lung, Pseudomonas aeruginosa is predominant, infecting over 50% of adults with CF, and becoming antibiotic-resistant over time. Current therapies for CF, while providing tremendous benefits, fail to eliminate persistent bacterial infections, chronic inflammation, and irreversible lung damage, necessitating novel therapeutic strategies. Our group engineered mesenchymal stromal cell derived extracellular vesicles (MSC EVs) to carry the microRNA let-7b-5p as a dual anti-infective and anti-inflammatory treatment. MSC EVs are low-immunogenicity platforms with innate antimicrobial and immunomodulatory properties, while let-7b-5p reduces biofilm formation and inflammation. In a preclinical CF mice model, we reported that let-7b-5p-loaded MSC EVs reduced P. aeruginosa burden, immune cells, and proinflammatory cytokines in the lungs. We hypothesize four complementary mechanisms for the observed in-vivo effects of the let-7b-5p loaded MSC EVs: antimicrobial activity, anti-inflammatory properties, inhibition of antibiotic-resistant P. aeruginosa biofilm formation in CF airways, and stimulation of anti-inflammatory macrophage behaviors. This study focused on the second and third mechanisms and demonstrates that MSC EVs engineered to contain let-7b-5p effectively blocked the formation of antibiotic-resistant P. aeruginosa biofilms on primary human bronchial epithelial cells (pHBECs) while also reducing P. aeruginosa -induced inflammation. This approach holds promise for improving outcomes for people with CF. Future work will focus on optimizing delivery strategies and expanding the clinical applicability of MSC EVs to target other CF-associated pathogens.

NEW AND NOTEWORTHY: This is the first study demonstrating that let-7b-5p loaded Mesenchymal Stromal Cell Extracellular Vesicles (MSC EVs) block antibiotic-resistant P. aeruginosa biofilm formation and reduce inflammation in CF primary human bronchial epithelial cells.

RevDate: 2025-06-12

Puerner C, Morelli KA, Kerkaert JD, et al (2025)

Transcriptional analysis of developing Aspergillus fumigatus biofilms reveals metabolic shifts required for biofilm maintenance.

bioRxiv : the preprint server for biology pii:2025.06.02.657448.

UNLABELLED: Aspergillus fumigatus is a filamentous fungus found in compost and soil that can cause invasive and/or chronic disease in a broad spectrum of individuals. Diagnosis and treatment of aspergillosis often occur during stages of infection when A. fumigatus has formed dense networks of hyphae within the lung. These dense hyphal networks are multicellular, encased in a layer of extracellular matrix, and have reduced susceptibility to contemporary antifungal drugs, characteristics which are defining features of a microbial biofilm. A mode of growth similar to these dense hyphal networks observed in vivo can be recapitulated in vitro using a static, submerged biofilm culture model. The mechanisms underlying filamentous fungal cell physiology at different stages of biofilm development remain to be defined. Here, we utilized an RNA sequencing approach to evaluate changes in transcript levels during A. fumigatus biofilm development. These analyses revealed an increase in transcripts associated with fermentation and a concomitant decrease in oxidative phosphorylation related transcripts. Further investigation revealed that ethanol and butanediol fermentation is important for mature biofilm biomass maintenance. Correspondingly, a gene (silG), a predicted transcription factor, was observed to also be required for mature biofilm biomass maintenance. Taken together, these data suggest temporal changes in A. fumigatus metabolism during biofilm development are required to maintain a fully mature biofilm.

IMPORTANCE: Aspergillus fumigatus is the most common etiological agent of a collection of diseases termed aspergillosis. Invasive P ulmonary A spergillosis (IPA), a severe form of aspergillosis, is highlighted by invasive growth of fungal hyphae into host lung tissue. Strains that are susceptible to antifungal therapies in vitro frequently fail to respond to treatment in vivo, resulting in high mortality rates even with treatment. It is now appreciated that this decreased antifungal efficacy in vivo is, in part, likely due to biofilm-like growth of the fungus. A. fumigatus biofilms have been shown to develop regions of limited oxygen availability that are hypothesized to induce cell quiescence and drug resistance. Understanding the mechanisms by which A. fumigatus induces, develops, and maintains biofilms to evade antifungal therapies is expected to illuminate biofilm-specific therapeutic targets. Here we present transcriptomics data of developing A. fumigatus biofilms and from these data define genes related to fungal fermentation and regulation of transcription important for maintenance of mature A. fumigatus biofilms.

RevDate: 2025-06-11

Thakur R, S Yadav (2025)

Exopolysaccharides and biofilm forming microbial inoculant AB-13 acting in a consortium promotes growth of economically important medicinal plant Catharanthus roseus.

International journal of biological macromolecules pii:S0141-8130(25)05675-2 [Epub ahead of print].

Biofilm and Exopolysaccharides (EPS) from bioinoculants have previously displayed industrial applications but their role as plant probiotics is underexplored. In this study, biofilm forming and exopolysaccharides producing microbe (AB-13) was isolated and molecular characterization was done along with plant growth promoting traits. Biofilm and EPS characterization was done by biophysical techniques like XRD, FTIR and SEM-EDAX which revealed amorphous nature, signature carbohydrate related peaks and surface morphology. Under natural conditions, pot experiments on Catharanthus roseus were conducted by supplementation of microbial consortium containing AB-13 and a previously reported AB-11 isolates. Multiple branching in shoots, roots and early flowering with delayed senescence over control plants were observed. The consortium efficiently boosted the growth of C. roseus plants with maximum shoot length of 42 ± 1.54 cm and root length of 17.05 ± 1.36 cm with an increase of 11 % and 18 % respectively as compared to control. In consortium inoculated plants, the maximum fresh weight (37.32 ± 1.78 g) and dry weight (5.77 ± 0.27 g) with an increase of fresh weight (41.55 %), dry weight (50.59 %) and total chlorophyll content (43.88 %) was recorded, as compared to control. Thus, we can conclude that the above microbial consortium promoted growth and development of economically important plant C. roseus.

RevDate: 2025-06-11

Chen H, Song C, Wang Q, et al (2025)

Advanced treatment of coal gasification wastewater using a multistage aerated biofilm reactor with hydrophilic polyurethane carriers.

Journal of environmental management, 389:126141 pii:S0301-4797(25)02117-6 [Epub ahead of print].

To address the challenges posed by the complexity and recalcitrance of coal gasification wastewater (CGW), this study developed a multistage aerated biofilm reactor incorporating hydrophilic polyurethane as the biofilm carrier for advanced treatment of CGW. The results demonstrated that the reactor exhibited excellent resistance to shock loads and effectively treated high concentrations of ammonia nitrogen (NH4[+]-N) and refractory organic compounds. At hydraulic retention times (HRTs) of 24 h, 12 h, and 8 h, the NH4[+]-N removal efficiency consistently exceeded 97 %, with complete conversion to nitrate. Notably, at an HRT of 12 h, the chemical oxygen demand (COD) removal efficiency reached a maximum of 42.68 ± 9.27 %. Further analyses using three-dimensional fluorescence spectroscopy and gas chromatography-mass spectrometry revealed high removal efficiencies of 75.66 %, 76.58 %, and 63.89 % for alkanes, phenolic compounds, and phthalate esters, respectively. The reactor's robust biofilm stability was confirmed by the high protein-to-polysaccharide ratio in extracellular polymeric substances (EPS) ranging from 3.35 to 5.85, with tightly bound EPS correlating significantly with biofilm stability. Microbial community analysis identified Nitrosomonas as the dominant ammonia-oxidizing bacteria (AOB), alongside Nitrospira and Candidatus_Nitrotoga as the key nitrite-oxidizing bacteria (NOB). Simultaneously, dominant genera including PLTA13, Fimbriimonadaceae, Blastocatellia 11-24, and Ahniella played key roles in degrading refractory organic compounds. These findings highlight the promising potential of the multistage aerated biofilm reactor for the efficient advanced treatment of CGW.

RevDate: 2025-06-11
CmpDate: 2025-06-11

Ramos LA, Walls EC, Petrucci MS, et al (2025)

Growth and Polarization of A549 Human Alveolar Epithelial Cells as a Model to Study Biofilm Formation in Acinetobacter baumannii.

Methods in molecular biology (Clifton, N.J.), 2942:35-44.

Acinetobacter baumannii is an opportunistic pathogen that has a propensity to cause infections in immunocompromised patients. With the increasing incidence of antibiotic-resistant isolates, Acinetobacter baumannii has emerged as one of the most problematic pathogens in recent decades with the World Health Organization urging prioritization for additional research focusing on this nosocomial pathogen. The following protocol outlines the process of culturing and polarizing A549 human alveolar epithelial cells for infection with Acinetobacter baumannii to study biofilm formation. The protocol additionally outlines the process of fixing the infected A549 cells for downstream applications.

RevDate: 2025-06-11

Anonymous (2025)

RETRACTION: Preparation and Optimization of Hydrophilic Modified Pullulan Encapsulated Tetracycline for Significant Antibacterial and Anti-Biofilm Activity Against Stenotrophomonas maltophilia Isolates.

Chemistry & biodiversity [Epub ahead of print].

RevDate: 2025-06-12

Buzisa Mbuku R, Poilvache H, Maigret L, et al (2025)

Targeting Staphylococcus aureus biofilm-related infections on implanted material with a novel dual-action thermosensitive hydrogel containing vancomycin and a tri-enzymatic cocktail: in vitro and in vivo studies.

Biofilm, 9:100288.

Implant-associated infections remain a critical challenge due to the presence of biofilm-forming bacteria, which enhance tolerance to conventional treatments. This study investigates the efficacy of a tri-enzymatic cocktail (TEC; DNA/RNA endonuclease, endo-14-β-d-glucanase, β-N-acetylhexosaminidase) targeting biofilm matrix components combined with supratherapeutic doses of antibiotics encapsulated in a thermosensitive hydrogel (poloxamer P407) for local administration. In vitro, the hydrogel formulation enabled controlled release of active agents over 12 h. Vancomycin and TEC co-formulated in hydrogel achieved up to 3.8 Log10 CFU count reduction and 80 % biofilm biomass reduction on MRSA biofilms grown on titanium coupons, demonstrating enhanced efficacy as compared to individual active agents, with 1.3-3.2 log10 additional killing. Fluoroquinolone efficacy remained unchanged by enzyme addition. In vivo, in a model of tissue cages containing titanium beads implanted in the back of guinea pigs, hydrogel-delivered vancomycin maintained therapeutic levels for seven days. Coupled with an intraperitoneal administration of vancomycin for 4 days, a single local administration of hydrogel containing both vancomycin and TEC was more effective than hydrogels containing either vancomycin or TEC, achieving an additional 2.1 Log10 CFU reduction compared to local vancomycin, 2.3 Log10 compared to local TEC, and 4.3 Log10 compared to systemic vancomycin treatment alone. However, partial regrowth occurred at later stages, indicating room for further optimization. Nevertheless, these findings already underscore the potential of combining a high dose of antibiotic with an enzymatic cocktail in a sustained-release hydrogel delivery system as a promising strategy for improving the management of biofilm-associated implant infections.

RevDate: 2025-06-10

Han Z, Zheng X, Zhao Z, et al (2025)

Revealing the characteristics and nitrogen metabolism mechanism of Anammox biofilm assisted by nanoscale zero-valent iron.

Journal of environmental management, 389:126137 pii:S0301-4797(25)02113-9 [Epub ahead of print].

Biofilm was an advanced approach to facilitating anaerobic ammonium oxidation (Anammox) application owing to high biomass retention and stable performance. The characteristics, nitrogen removal kinetics and microbial metabolic mechanism of Anammox biofilm with intermittent dosing of nanoscale zero-valent iron (nZVI) were comprehensively revealed. Anammox biofilm was acclimated efficiently with nZVI assistance within 110 days. nZVI stimulated the secretion of EPS, especially T-EPS and PN, which showed key importances in biofilm formation. The nitrogen removal kinetics were accurately described and predicted by the modified Boltzmann model. High-throughput sequencing revealed that the microbial richness and diversity gradually declined, while AnAOB were enriched from 0.12 % to 1.34 %. Furthermore, key functional genes involved in the Anammox pathway (e.g., hdh and hzsA/B/C) were enriched by 427.90-596.49 %. Anammox process was the dominant in the system, cooperating with other pathways driven by the Fe(II)/Fe(III) cycle. This study provided innovative insights into the enhanced mechanism of nZVI on Anammox.

RevDate: 2025-06-10

Lin C, Lin F, Wang J, et al (2025)

Mupirocin-Piperine Microemulsion Hydrogels Accelerate Healing of Infected Wounds through Deep Penetration and Biofilm Disruption.

Molecular pharmaceutics [Epub ahead of print].

The emergence of bacteria resistant to multiple first-line antibiotics has created an urgent demand for effective alternatives and a comprehensive approach to the healing of infected wounds. This study developed synergistic microemulsion hydrogels (Mup-Pip-ME-gels) combining piperine's biofilm-disrupting properties with mupirocin's antibacterial activity to combat antibiotic resistance and enhance wound healing. The optimization of the formulation was carried out using a pseudoternary phase diagram and response surface methodology, resulting in a microemulsion with stable physical properties: an average particle size of 57.54 nm and a zeta potential of -15.3 mV. This microemulsion was then incorporated into hydroxypropyl methylcellulose-based hydrogels for further investigation. The results demonstrated that the hydrogels exhibited excellent stability, minimal skin irritation, and significantly enhanced cumulative permeation compared with commercial products (Bactroban). Mup-Pip-ME-gels showed the largest inhibition zones against both Staphylococcus aureus and MRSA, measuring 46.0 ± 0.20 and 50.5 ± 0.50 mm, respectively, and achieved a significant biofilm disruption with inhibition rates of 85.0 ± 0.3% and 81.2 ± 0.7%. Pharmacodynamic studies indicated a 2.2-fold increase in the wound healing rate and a significant reduction in bacterial count (P < 0.01) by day 7. Overall, by combining natural compounds and antibiotics, Mup-Pip-ME-gels enhance transdermal permeation and wound healing while addressing antibiotic resistance, offering an effective topical treatment for bacterial infections.

RevDate: 2025-06-10

Sandim GC, Sardi JCO, da Silva ACB, et al (2025)

Exploring the Antimicrobial Potential of a Peptide Against Mixed Biofilm of Staphylococcus aureus and Candida albicans.

Probiotics and antimicrobial proteins [Epub ahead of print].

Candida albicans and Staphylococcus aureus species are, respectively, the most common fungal and bacterial agents isolated from bloodstream infections worldwide. In addition, 20% of all C. albicans bloodstream infections have been shown to be polymicrobial in nature, and the bacterium Staphylococcus aureus is the third most common co-isolated organism. Finding an efficient treatment strategy for polymicrobial infections is a major challenge, as traditional therapies most often target only individual agents within specific realms. Thus, the present study investigated the antimicrobial and anti-biofilm polymicrobial activity of the peptide ITR-16, a new synthetic peptide against microorganisms with a high incidence in nosocomial infections. This peptide was tested against S. aureus and C. albicans in planktonic form and mono and polymicrobial biofilm. Synergism assays with other common antimicrobials were performed. The ITR-16 peptide was also tested for its preliminary acute toxicity in an in vivo model of Galleria mellonella. The ITR-16 peptide showed antimicrobial activity, with minimal inhibitory concentrations (MICs) ranging from 0.62 to 2.5 µM. And treatment with ITR-16 at 10 × MIC significantly reduced biofilm formation and viability of S. aureus and C. albicans strains in both monospecies and polymicrobial biofilms. Furthermore, it demonstrated low toxicity in the G. mellonella model at anti-biofilm concentrations. These results present a new molecule with potential polymicrobial anti-biofilm activity.

RevDate: 2025-06-10

Wang L, Hou W, Wang H, et al (2025)

Nontargeted metabolomics analysis to unravel the anti-biofilm mechanism of Citrocin on Listeria monocytogenes.

Microbiology spectrum [Epub ahead of print].

Listeria monocytogenes biofilm formation is an important cause of cross-contamination in food processing. Citrinin is a potential broad-spectrum antimicrobial peptide. However, the effects of Citrocin on L. monocytogenes and its biofilm, as well as the associated mechanisms, remain to be explored. In this study, we evaluated the anti-biofilm effect of the antimicrobial peptide Citrocin on the foodborne pathogen L. monocytogenes and analyzed its anti-biofilm mechanism from the perspectives of swarming motility, extracellular polysaccharide production, and metabolite level changes. The results showed that Citrocin had a significant inhibitory effect on the growth of L. monocytogenes, with a minimum inhibitory concentration (MIC) of 0.075 mg/mL and a minimum bactericidal concentration (MBC) of 0.15 mg/mL. Citrocin at concentrations of MIC, 2 × MIC, and 4 × MIC could prevent biofilm formation and remove established biofilms. Metabolomics analysis revealed that Citrocin at 0.3 mg/mL caused a significant differential expression of metabolites in biofilms, up- and downregulating 23 and 13 metabolites, consisting mainly of amino acids, organic acids, and fatty acids, respectively. In addition, Citrocin significantly enriched energy and amino acid metabolic pathways, including alanine, glutamate, aspartate metabolism, TCA cycle, and arginine biosynthesis. This work provides potential biofilm regulation strategies and serves as a theoretical basis for the prevention and treatment of listeriosis.IMPORTANCEListeria monocytogenes biofilm formation is an important cause of cross-contamination during food processing. We found that Citrocin, an antimicrobial peptide that is widely used in animal feed, has good antimicrobial and anti-biofilm effects against L. monocytogenes. We preliminarily explored the anti-biofilm mechanism of Citrocin in terms of swarming motility, extracellular polysaccharide production, and metabolomics. Our work demonstrated that Citrocin is an excellent antimicrobial agent, which is important for the control of food cross-contamination and the preventive treatment of listeriosis.

RevDate: 2025-06-09

Behm AM, Yao H, Eze EC, et al (2025)

Inhibitors of the Bacterioferritin Ferredoxin Complex Dysregulate Iron Homeostasis and Kill Acinetobacter baumannii and Biofilm-Embedded Pseudomonas aeruginosa Cells.

ACS infectious diseases [Epub ahead of print].

In Pseudomonas aeruginosa, the iron storage protein bacterioferritin (Bfr) contributes to buffering cytosolic free iron concentrations by oxidizing Fe[2+] and storing the resultant Fe[3+] in its internal cavity, and by forming a complex with a cognate ferredoxin (Bfd) to reduce the stored Fe[3+] and mobilize Fe[2+] to the cytosol. Small molecule derivatives of 4-aminoisoindoline-1,3-dione designed to bind P. aeruginosa Bfr (Pa Bfr) at the Bfd binding site accumulate in the P. aeruginosa cell, block the Pa Bfr-Bfd complex, inhibit iron mobilization from Pa Bfr, elicit an iron starvation response, are bacteriostatic to planktonic cells, and are bactericidal to biofilm-entrenched cells. A structural alignment of Pa Bfr and Acinetobacter baumannii Bfr (Ab Bfr) showed strong conservation of the Bfd binding site on Ab Bfr. Accordingly, the small molecule inhibitors of the Pa Bfr-Bfd complex accumulate in the A. baumannii cells, elicit an iron starvation response, are bactericidal to planktonic cells, and exhibit synergy with existing antibiotics. These findings indicate that the inhibition of iron mobilization from Bfr may be an antimicrobial strategy applicable to other Gram-negative pathogens.

RevDate: 2025-06-09

Afify MGE, Gomaa OM, El Kareem HA, et al (2025)

Promoting bacterial colonization and biofilm formation for enhanced biodegradation of low-density polyethylene microplastics.

Bioresources and bioprocessing, 12(1):59.

The accumulation of plastic waste presents a significant worldwide environmental challenge. This study aimed to isolate polyethylene-degrading bacteria from marine samples containing plastic waste. Four culturable bacterial isolates: Micrococcus luteus, Bacillus cereus, Enterococcus faecalis, and Actinomyces sp. were assessed for their biofilm formation, biosurfactant, and protease production. Gamma irradiation was used to induce structural changes and promote bacterial colonization and biofilm formation on low-density polyethylene microplastics (LDPE MPs). Optimal biofilm formation was achieved in minimal media supplemented with 30% tryptic soy broth, 10% biosurfactant, and 300 µM calcium chloride. The factorial design experiment demonstrated that adding media supplementation significantly improved bacterial colonization and biofilm formation when compared to gamma irradiation. This was supported with Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX) mapping, and Fourier Transform Infrared Spectroscopy (FTIR). The optimized LDPE MP degradation was achieved through a multi-step protocol: (1) samples are pre-treated to 40 kGy gamma irradiation, which resulted in 5.7% Gravimetric weight loss and structural and morphological changes, (2) incubation in biofilm inducing media overnight, and (3) further incubation in minimal media for 30 days. This approach resulted in a total weight loss of 22.5%. In conclusion, synergistic pre-treatment is recommended to promote biofilm and improve biodegradation of LDPE MPs by marine bacteria.

RevDate: 2025-06-09

Danelon M, Nunes GP, Sterzenbach T, et al (2025)

Enhancing antimicrobial properties of glass ionomer cement through metallic agent reinforcement: A systematic review and meta-analysis: Alteration of the biofilm with metallic metal agents.

Journal of dentistry pii:S0300-5712(25)00336-7 [Epub ahead of print].

OBJECTIVES: This systematic review and meta-analysis (SRM) aimed to assess the impact of incorporating metallic agents into glass ionomer cement (GIC) and resin-modified glass ionomer cement (RMGIC) on their microbiological properties and antibacterial activity.

DATA SOURCES: Following PRISMA guidelines, the SRM included studies published up to August 21, 2024.

STUDY SELECTION: The eligibility criteria included clinical trials, in situ, and in vitro studies. The data were analyzed using RevMan software, and bias risk was assessed with the Joanna Briggs Institute's Checklist for in vitro studies and the ROBINS-I tool for clinical trials.

RESULTS: Out of 2,393 screened records, 32 studies were included. Results showed that metallic agents like silver, zinc oxide, titanium dioxide, and copper enhanced the antimicrobial properties of GIC and RMGIC. Most studies reported superior antimicrobial effects compared to controls, with only two studies showing neutral effects. Meta-analysis revealed that GIC with 5% TiO₂ or 2% ZnO nanoparticles significantly reduced S. mutans viability, while silver zeolite at 1% and 5% concentrations showed strong effects. Similarly, adding silver or ZnO to RMGIC improved its activity against S. mutans and L. acidophilus. The studies showed a low risk of bias.

CONCLUSIONS: Metallic agents enhance the antimicrobial efficacy of GIC/RMGIC, offering a promising solution for biofilm control in dental restorations. However, further research is needed to optimize their clinical application, particularly through in vivo studies, and to assess their impact on mechanical, esthetic, and cytotoxic properties.

CLINICAL RELEVANCE: Incorporating metallic agents into GIC and RMGIC enhances their antibacterial properties, improving biofilm control in dental restorations. This modification may reduce the risk of secondary caries and prolong restoration longevity.

RevDate: 2025-06-09
CmpDate: 2025-06-09

Lei B, Liu J, Zhao S, et al (2025)

Plaque disclosing agent as a plaque control guide for oral hygiene in chronic periodontitis based on guided biofilm therapy: A retrospective cohort study.

Medicine, 104(23):e42782.

We assessed the effectiveness of plaque disclosing agents as a visual aid for biofilm removal during professional oral hygiene instruction. A total of 220 patients with chronic periodontitis were enrolled in the study and divided into a control group (CG; traditional interventions) and an observation group (OG; guided biofilm therapy concepts applied). Plaque index (PI), bleeding on probing (BOP), and pocket depth (PD) were compared between the 2 groups. Self-care efficacy scale scores were assessed and compared, and oral hygiene behaviors were evaluated. After a 3-month intervention, the PI, BOP, and PD in OG reduced compared with those in CG. The total scores of the self-care efficacy scale in OG were higher than those in CG. The application of guided biofilm therapy concepts in the treatment and maintenance of patients with chronic periodontitis proves effective in reducing PI, BOP, and PD levels, enhancing patients' oral health management abilities, and ensuring sustained therapeutic outcomes.

RevDate: 2025-06-09
CmpDate: 2025-06-09

Lekhwar R, Kumar S, Tripathi M, et al (2025)

Novel therapeutic strategies targeting infections caused by P. aeruginosa biofilm.

Molecular biology reports, 52(1):571.

Pseudomonas aeruginosa is a gram-negative clinical pathogen, particularly affecting immunocompromised patients, those with cystic fibrosis, and burn victims. It causes chronic infections, especially in hospital settings, and is a significant contributor to nosocomial infections. Its capacity to create biofilms resistant to antibiotics is the reason for its infamous persistence in clinical settings. P. aeruginosa infections can affect any area of the body because the bacteria's biofilm enables it to stick to any surface, living or non-living. One of the primary clinical challenges in treating P. aeruginosa biofilm is its noteworthy resistance to many classes of antibiotics. The bacterium's ability to acquire resistance through efflux pumps, beta-lactamase production, and genetic mutations complicates treatment options. Recently, multidrug- resistant (MDR) strains of P. aeruginosa are becoming increasingly prevalent, limiting the efficacy of traditional antibiotics and leading to the need for alternative therapies. There is an ongoing need for novel treatment options, including bacteriophage therapy, antimicrobial peptides, and vaccines. The rapid adaptability of P. aeruginosa and its ability to develop resistance underscores the importance of continued research into new therapeutic strategies. This review discusses the various therapeutic strategies like; antimicrobial therapy, targeting efflux pumps and biofilms of P. aeruginosa, phage therapy, immunotherapy and nanotechnology to explore the mechanisms, through which antimicrobial compounds interact with biofilm structures and the bacteria within.

RevDate: 2025-06-09

Peremore C, van 't Hof C, Nkosi CL, et al (2025)

Biofilm characterisation of the maize rot-causing pathogen, Fusarium verticillioides.

Biofouling [Epub ahead of print].

Biofilm formation was investigated in a maize rot-causing pathogen, Fusarium verticillioides. This work revealed that in vitro cultures produce structured, adherent communities with a dense extracellular matrix (ECM) surrounding hyphae that makes up the biomass of a matured biofilm. Pellicle containing exopolysaccharide had a hydrodynamic diameter of 4.19 nm and a low viscosity (0.022 dl/g). The exopolysaccharide was composed of amino sugars and unordered, facilitating stability through complexation with the anionic eDNA. Biofilm formation varied over different pH and temperature values, emphasising its role in promoting adaption, survival, and persistence in F. verticillioides, potentially contributing to its pathogenicity in maize. Collectively, the results provide valuable insights into biofilm structure and stress resistance in this fungus, and will serve as a foundation for future studies incorporating in planta infection systems.

RevDate: 2025-06-09

Cattò C, Fassi EMA, Grazioso G, et al (2025)

Insights on Zosteric Acid Analogues Activity Against Candida albicans Biofilm Formation.

ACS omega, 10(21):22285-22295.

Zosteric acid (ZA), or p-(sulphooxy)-cinnamic acid, is a secondary metabolite of the seagrass Zostera marina able to reduce biofilm formation of a wide range of bacteria and fungi, through a nonbiocidal mode of action. However, the lack of information concerning the specific chemical structural elements responsible for ZA's antibiofilm activity has hindered the scaling up of this green-based technology for real applications. In this study, a small library of molecules based on ZA scaffold diversity was screened against the eukaryotic fungus Candida albicans, in order to identify the key chemical features of ZA necessary for inhibiting fungal biofilm at sublethal concentrations. Results, supported by multivariate statistical analysis, revealed that the presence of (i) the trans (E) double bond, (ii) the free carboxylic group in the side chain, and (iii) the para substitution with a hydroxyl group were all instrumental for maintaining the antibiofilm activity of the molecules. Additionally, molecular modeling studies suggested that the best performing derivatives interacted with NADP-(H) quinone oxidoreductase, influencing the microbial redox balance.

RevDate: 2025-06-09

Yuan X, Chao C, Niu J, et al (2025)

Mechanistic insights into nitrogen removal performance and electron competition with mixed electron donor supply in a biofilm electrode reactor.

Eco-Environment & Health, 4(2):100153.

In this study, a unique electrode configuration in the form of an "inverted T" was developed in the biofilm electrode reactor (BER), enabling superior nitrogen removal via the synergistic effect of hydrogen autotrophic denitrification and heterotrophic denitrification. In contrast to the sole heterotrophic denitrification in the biofilm reactor (BR), weak electric stimulation in the BER system promoted in situ hydrogen production as well as electron transport and utilization, resulting in a notable 20% improvement in NO 3 - removal efficiency for both influent COD/N ratios. Conversely, notable NO 2 - accumulation occurred under both COD/N ratios, with concentrations ranging from 6.0 to 8.0 mg/L. The enrichment of non-heterotrophic denitrifiers, such as Thermomonas, Pelomonas, and Hydrogenophaga, was observed in the BER with a relative abundance exceeding 1.0%, contributing to the hydrogen autotrophic denitrification pathway. Based on the outcomes of the multiple electron donor utilization in the coexistence of different electron acceptor combinations, despite H2 serving as an additional electron donor in the BER, electron competition was still detectable. Notably, nitrite reductase (Nir) emerged as the weakest competitor, resulting in a constrained NO 2 - reduction capacity. Based on the analysis of the electron competition characteristic, the potential NO 3 - metabolic pathway in the BER system was primarily driven by heterotrophic denitrification processes. The introduced electricity in the BER system was favorable for facilitating nitrogen removal through in situ production of hydrogen, direct supply of electrons from the electrode, improvement of functional microbial activity, and enhancement of enzymatic activity.

RevDate: 2025-06-08
CmpDate: 2025-06-08

García-Viñola V, Ezenarro J, Reguant C, et al (2025)

Interaction effects of fumaric acid, pH and ethanol on the growth of lactic and acetic acid bacteria in planktonic and biofilm states.

Food microbiology, 131:104808.

The microbial stability of wine can be compromised by the presence of lactic acid bacteria (LAB) and acetic acid bacteria (AAB), which can cause spoilage via off flavour production, increased acetic acid production, or biofilm formation. To manage the growth of LAB in winemaking, fumaric acid (FA) has been proposed as an alternative to traditional antimicrobial agents, such as sulfur dioxide (SO2). This study aimed to evaluate the inhibitory effects of FA on the growth of LAB and AAB based on the influence of pH and ethanol in a synthetic wine-like medium. The research involved the determination of the individual, 2 × 2 combined, and combined minimum inhibitory concentrations (MICs) of fumaric acid, pH, and ethanol. Specifically, the MIC90 was defined as the concentration required to inhibit the growth of more than 90 % of the initial population, and the MIC50 was defined as the concentration required to inhibit the growth of more than 50 % of the initial population. These thresholds were assessed in 19 bacterial strains (13 LAB and 6 AAB strains) at pH values of 3.5 and 4.0 and ethanol concentrations of 0, 4, 8 and 12 % v/v. Additionally, the impact of FA on biofilm formation was evaluated in the ten bacterial strains that were observed to be most resistant to FA. The results revealed that the inhibitory effects of FA were enhanced at lower pH values and at higher ethanol concentrations. LAB strains (such as Oenococcus oeni) were particularly sensitive to FA, whereas non-Oenococcus LAB strains demonstrated resistance to concentrations exceeding 2 g/L under the tested pH (3.5-4.0) and ethanol (0-12 % v/v) conditions. AAB strains (such as Acetobacter aceti) tolerated FA concentrations greater than 2 g/L at pH 4.0 in the absence of ethanol; however, the susceptibility increased with increasing ethanol concentrations and decreasing pH. Furthermore, FA significantly inhibited biofilm formation (particularly at a pH of 3.5 and ethanol concentrations greater than 8 % v/v). In conclusion, when combined with low pH and high ethanol concentrations, FA offers a promising strategy for controlling bacterial growth and biofilm formation in winemaking. This approach has the potential to complement or replace the use of traditional chemical preservatives, such as SO2.

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RJR Experience and Expertise

Researcher

Robbins holds BS, MS, and PhD degrees in the life sciences. He served as a tenured faculty member in the Zoology and Biological Science departments at Michigan State University. He is currently exploring the intersection between genomics, microbial ecology, and biodiversity — an area that promises to transform our understanding of the biosphere.

Educator

Robbins has extensive experience in college-level education: At MSU he taught introductory biology, genetics, and population genetics. At JHU, he was an instructor for a special course on biological database design. At FHCRC, he team-taught a graduate-level course on the history of genetics. At Bellevue College he taught medical informatics.

Administrator

Robbins has been involved in science administration at both the federal and the institutional levels. At NSF he was a program officer for database activities in the life sciences, at DOE he was a program officer for information infrastructure in the human genome project. At the Fred Hutchinson Cancer Research Center, he served as a vice president for fifteen years.

Technologist

Robbins has been involved with information technology since writing his first Fortran program as a college student. At NSF he was the first program officer for database activities in the life sciences. At JHU he held an appointment in the CS department and served as director of the informatics core for the Genome Data Base. At the FHCRC he was VP for Information Technology.

Publisher

While still at Michigan State, Robbins started his first publishing venture, founding a small company that addressed the short-run publishing needs of instructors in very large undergraduate classes. For more than 20 years, Robbins has been operating The Electronic Scholarly Publishing Project, a web site dedicated to the digital publishing of critical works in science, especially classical genetics.

Speaker

Robbins is well-known for his speaking abilities and is often called upon to provide keynote or plenary addresses at international meetings. For example, in July, 2012, he gave a well-received keynote address at the Global Biodiversity Informatics Congress, sponsored by GBIF and held in Copenhagen. The slides from that talk can be seen HERE.

Facilitator

Robbins is a skilled meeting facilitator. He prefers a participatory approach, with part of the meeting involving dynamic breakout groups, created by the participants in real time: (1) individuals propose breakout groups; (2) everyone signs up for one (or more) groups; (3) the groups with the most interested parties then meet, with reports from each group presented and discussed in a subsequent plenary session.

Designer

Robbins has been engaged with photography and design since the 1960s, when he worked for a professional photography laboratory. He now prefers digital photography and tools for their precision and reproducibility. He designed his first web site more than 20 years ago and he personally designed and implemented this web site. He engages in graphic design as a hobby.

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An examination of the research and translational application to prevent and treat biofilm-associated diseases In the decade since the first edition of Microbial Biofilms was published, the interest in this field has expanded, spurring breakthrough research that has advanced the treatment of biofilm-associated diseases. This second edition takes the reader on an exciting, extensive review of bacterial and fungal biofilms, ranging from basic molecular interactions to innovative therapies, with particular emphasis on the division of labor in biofilms, new approaches to combat the threat of microbial biofilms, and how biofilms evade the host defense.

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Collection of publications by R J Robbins

Reprints and preprints of publications, slide presentations, instructional materials, and data compilations written or prepared by Robert Robbins. Most papers deal with computational biology, genome informatics, using information technology to support biomedical research, and related matters.

Research Gate page for R J Robbins

ResearchGate is a social networking site for scientists and researchers to share papers, ask and answer questions, and find collaborators. According to a study by Nature and an article in Times Higher Education , it is the largest academic social network in terms of active users.

Curriculum Vitae for R J Robbins

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Curriculum Vitae for R J Robbins

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