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Introduction: Woodchips as a source of particulate organic carbon (POC) are proposed as a nature-based solution to enhance nutrient uptake and retention in agricultural streams. However, the effective implementation of woodchips for nutrient removal in streams requires an advanced understanding of their potential and limits, considering their performance under various environmental conditions. This study tested the efficiency of woodchips on the uptake of soluble reactive phosphorus (SRP) and ammonium (N-NH4) across different experimental scales and complexity. We investigated whether the presence of woodchips can increase SRP and N-NH4 uptake in laboratory flumes under controlled conditions, outdoor flumes under semi-controlled conditions, and agricultural streams. Additionally, we examined how the effects of woodchips will change over time via a 6-week incubation in the outdoor flumes. Methods: The woodchips were pre-colonized for four weeks to allow the growth of biofilms. We performed short-term nutrient additions without (control) and with (treatment) woodchips in all three experimental setups. Uptake parameters were determined via concentration changes over time in the laboratory flumes and concentration changes over travel distance in the outdoor flumes and the stream channels. The effects of woodchips on SRP and N-NH4 uptake rates were analyzed using an effect size model. Results: We found positive effects of woodchips on nutrient uptake only in the laboratory flumes but no or even negative effects in the outdoor flumes and the agricultural streams. Over the 6-week incubation in the outdoor flumes, we did not observe significant changes in the effects of woodchips on nutrient uptake. Discussion: These findings highlight that considering experimental scales and influencing environmental conditions is crucial when testing the application of woodchips as nature-based solutions to mitigate nutrient loads in agricultural streams. [ABSTRACT FROM AUTHOR]

Bacterial biofilms have been implicated in several chronic infections. After initial attachment, a critical first step in biofilm formation is a cell inducing a surface-sensing response. In the Gram-negative opportunistic pathogen Pseudomonas aeruginosa, two second messengers, cyclic diguanylate monophosphate (c-di-GMP) and cyclic adenosine monophosphate (cAMP), are produced by different surface-sensing mechanisms. However, given the disparate cellular behaviors regulated by these second messengers, how newly attached cells coordinate these pathways remains unclear. Some of the uncertainty relates to studies using different strains, experimental systems, and usually focusing on a single second messenger. In this study, we developed a tricolor reporter system to simultaneously gauge c-di-GMP and cAMP levels in single cells. Using PAO1, we show that c-di-GMP and cAMP are selectively activated in two commonly used experimental systems to study surface sensing. By further examining the conditions that differentiate a c-di-GMP or cAMP response, we demonstrate that an agarose-air interface activates cAMP signaling through type IV pili and the Pil-Chp system. However, a liquid-agarose interface favors the activation of c-di-GMP signaling. This response is dependent on flagellar motility and correlated with higher swimming speed. Collectively, this work indicates that c-di-GMP and cAMP signaling responses are dependent on the surface context. [ABSTRACT FROM AUTHOR]

Dental caries and periodontitis are the most common oral diseases in humans and the main causes of tooth loss. Streptococcus mutans is primarily responsible for dental caries and dental plaque, which are triggered by biofilm formation on the tooth surface. In this study, biofilm inhibition by 4-isopropyl-3-methylphenol (IPMP)-based agents, consisting of IPMP and polyoxyethylene-hydrogenated castor oil (POEHCO), was investigated in vitro. Notably, the use of POEHCO in addition to IPMP inhibited S. mutans biofilms more drastically than IPMP alone. Moreover, the effects of IPMP on the expression of biofilm-related genes (gtfB, gtfC, and gtfD) were examined using quantitative real-time PCR. IPMP at sub-minimum inhibitory concentrations significantly downregulated the expression of these genes. These results suggested that the inhibitory effects on biofilm formation were synergistically enhanced by the surfactant and antibiofilm activities of IPMP. Therefore, IPMP-based agents as dentifrices may be useful to prevent oral diseases originating from biofilms. [ABSTRACT FROM AUTHOR]

We evaluated by comparing the performance of three pneumatically-driven bioreactors in the production of L-asparaginase (L-ASNase), an enzyme used to treat leukaemia and lymphoma. A two-step screening process was conducted to detect Cunninghamella spp. strains producing L-ASNase. Cunninghamella echinulata DSM1905 produced the highest levels of L-ASNase during screening assays. Subsequently, fermentations were performed in bubble column (BCR), airlift (ALR), and hybrid fixed-bed airlift (FB-ALR) bioreactors to determine the best upstream bioprocess. Mycelial biomass production was higher in BCR than in ALR and FB-ALR (p ≤ 0.0322). The activity of L-ASNase produced in FB-ALR, in which the fungus grew as a consistent biofilm, was significantly higher (p ≤ 0.022) than that from ALR, which was higher than that of BCR (p = 0.036). The specific activity of ALR and FB-ALR presented no differences (p = 0.073), but it was higher than that of BCR (p ≤ 0.032). In conclusion, C. echinulata DSM1905, grown under the biofilm phenotype, produced the highest levels of L-ASNase, and FB-ALR was the best upstream system for enzyme production. [ABSTRACT FROM AUTHOR]

Bacterial vaginosis (BV), the most common vaginal infection worldwide, is characterized by the development of a polymicrobial biofilm on the vaginal epithelium. While Gardnerella spp. have been shown to have a prominent role in BV, little is known regarding how other species can influence BV development. Thus, we aimed to study the transcriptome of Gardnerella vaginalis, Fannyhessea vaginae, and Prevotella bivia, when growing in triple-species biofilms. Single and triple-species biofilms were formed in vitro, and RNA was extracted and sent for sequencing. cDNA libraries were prepared and sequenced. Quantitative PCR analysis (qPCR) was performed on the triple-species biofilms to evaluate the biofilm composition. The qPCR results revealed that the triple-species biofilms were mainly composed by G. vaginalis and P. bivia was the species with the lowest percentage. The RNA-sequencing analysis revealed a total of 432, 126, and 39 differentially expressed genes for G. vaginalis, F. vaginae, and P. bivia, respectively, when growing together. Gene ontology enrichment of G. vaginalis downregulated genes revealed several functions associated with metabolism, indicating a low metabolic activity of G. vaginalis when growing in polymicrobial biofilms. This work highlighted that the presence of 3 different BV-associated bacteria in the biofilm influenced each other's transcriptome and provided insight into the molecular mechanisms that enhanced the virulence potential of polymicrobial consortia. These findings will contribute to understand the development of incident BV and the interactions occurring within the biofilm. [ABSTRACT FROM AUTHOR]

The eradication of recalcitrant bacterial biofilm infections necessitates the development of speedy diagnostics and prompt therapeutics. However, constructing a portable versatile platform that enables in situ monitoring of biofilm infections accompanied by potent antibiofilm activity remains challenging. To address this conundrum, a microneedle theranostic patch (Mn: C/G@MN) is devised by incorporating an innovative biophotonic probe (manganese‐doped carbon dots, Mn: CDs) into methacrylated gelatin for visual monitoring of biofilm infection and on‐demand photo‐therapy. The Mn: C/G@MN patch penetrates the physical barrier of biofilms to track their acidic microenvironment, exhibiting a visualized fluorescence color change (from yellow to turquoise) to enable naked‐eye monitoring of biofilm infection. Furthermore, the Mn: C/G@MN patch can drastically eradicate biofilm on‐demand through the synergy of local hyperthermia and hydroxyl radical (•OH) storm under 808 nm near‐infrared light illumination, enabling the damaging of extracellular polymeric substances (EPS) matrix to disperse biofilms and subsequently kill detached bacteria. Both in vitro and in vivo findings authenticate that biofilm infection monitoring‐and‐treating can be achieved. Moreover, the versatile Mn: C/G@MN patch is conducive to suppressing inflammatory responses, expediting collagen deposition, stimulating angiogenesis, and accelerating biofilm‐infected wound healing. As envisaged, this work highlights the potential of such a versatile platform for application in integrated theranostics for biofilm infection. [ABSTRACT FROM AUTHOR]

Protein filaments are ubiquitous in nature and have diverse biological functions. Cryo-electron microscopy (cryo-EM) enables the determination of atomic structures, even from native samples, and is capable of identifying previously unknown filament species through high-resolution cryo-EM maps. In this study, we determine the structure of an unreported filament species from a cryo-EM dataset collected from Bacillus amyloiquefaciens biofilms. These filaments are composed of GerQ, a spore coat protein known to be involved in Bacillus spore germination. GerQ assembles into a structurally stable architecture consisting of rings containing nine subunits, which stacks to form filaments. Molecular dockings and model predictions suggest that this nine-subunit structure is suitable for binding CwlJ, a protein recruited by GerQ and essential for Ca2+-DPA induced spore germination. While the assembly state of GerQ within the spores and the direct interaction between GerQ and CwlJ have yet to be validated through further experiments, our findings provide valuable insights into the self-assembly of GerQ and enhance our understanding of its role in spore germination. Here, the authors structurally characterise a protein filament species composed of the spore coat protein GerQ using cryo-EM. The nine-subunit assembly sheds light on spore biology and hints at an interaction with CwlJ, a protein required for spore germination. [ABSTRACT FROM AUTHOR]

Background: The aim of the randomized controlled clinical trial study was to evaluate the effectiveness in reducing pathologically increased pocket probing depths (PPD > 3 mm) using the Guided Biofilm Therapy (GBT) protocol (adapted to the clinical conditions in non-surgical periodontal therapy (NSPT): staining, air-polishing, ultrasonic scaler, air-polishing) compared to conventional instrumentation (staining, hand curettes/sonic scaler, polishing with rotary instruments) both by less experienced practitioners (dental students). Methods: All patients were treated according to a split-mouth design under supervision as diseased teeth of quadrants I/III and II/IV randomly assigned to GBT or conventional treatment. In addition to the treatment time, periodontal parameters such as PPD and bleeding on probing (BOP) before NSPT (T0) and after NSPT (T1: 5 ± 2 months after T0) were documented by two calibrated and blinded examiners (Ethics vote/ Trial-register: Kiel-D509-18/ DRKS00026041). Results: Data of 60 patients were analyzed (stage III/IV: n = 36/ n = 24; grade A/ B/ C: n = 1/ n = 31/ n = 28). At T1, a PPD reduction of all diseased tooth surfaces was observed in 57.0% of the GBT group and 58.7% of the control group (p = 0.067). The target endpoint (PPD ≤ 4 mm without BOP) was achieved in 11.5% for GBT (conventional treatment: 11.2%; p = 0.714). With the exception for number of sites with BOP, which was at T1 15.9% in the GBT group and 14.3% in the control group (p < 0.05) no significant differences between the outcomes of the study were found. At 30.3(28.3) min, the treatment time was significantly shorter in GBT than in the control group at 34.6(24.5) min (p < 0.001). Conclusions: With both protocols (GBT/ conventional instrumentation) comparably good clinical treatment results can be achieve in NSPT in stage III-IV periodontitis patients. Trial registration: The study was registered before the start of the study and can be found under the number DRKS00026041 in the German Clinical Trials Register. The registration date was 19/08/2021. [ABSTRACT FROM AUTHOR]

Introduction: Orthodontic clear aligners and retainers have numerous advantages that is making them ever increasingly popular. However, they might, similar to any other oral appliance, contribute to biofilm formation and finally dental caries or white spot lesions or gingival inflammations. The literature on biofilm formation on orthodontic clear appliances is very scarce and limited to a few microorganisms and materials. Therefore, this experimental study evaluated the biofilm formation on 5 thermoformed and 3D printed CAD/CAM orthodontic retainers in 3 intervals. Methods: In this in vitro study, 345 specimens (270 test discs and 45 negative controls) were created from fabricated retainers. Retainers included a 3D printed CAD/CAM material (Detax) and four thermoformed retainers [Erkodent (polyethylene terephthalate glycol [PETG]); EasyVac (polyethylene); DB (polyester based on terephthalic acid); and Clear Tech]. They were all 1 mm thick, and all completely fabricated, i.e., heated or printed. The discs were placed in 96-well plates. Microorganisms were cultured on 270 discs for 24 h (90 discs), 72 h (90 other discs), and 5 days or 120 h (90 other discs). Biofilm formation of the strains and negative controls was measured using the microtiter plate assay by ELISA reading. The microbes' ability to produce biofilm was categorized based on the comparison of average optical density (OD) of tests versus a cut-off point OD (ODc) calculated as the average of the OD of corresponding negative controls plus 3× its standard deviation: non-biofilm former [OD ≤ ODc], weak biofilm former [ODc < OD ≤ (2 × ODc)], moderate biofilm former [(2 × ODc) < OD ≤ (4 × ODc)], and strong biofilm former [(4 × ODc) < OD]. These were also converted to ranked scores between zero (no biofilm) and 3. The difference between ODs with control ODs were calculated. These were analyzed using 3-way ANOVA, 2-way ANOVA, and Tukey tests (α = 0.05, α = 0.008). Results: The 3-way ANOVA showed that the overall difference among the ΔODs of 5 retainers (all microorganisms and all intervals combined, n = 270) was not significant (F = 1.860, P = 0.119). Nevertheless, the difference among 3 intervals (F = 31.607, P = 0.0000) and the difference among the 6 microorganisms (F = 24.044, P = 0.0000) were significant. According to the Tukey test, the differences between the 1st interval with either of the other two intervals was significant (both P values = 0.000). There were significant differences between Candida albicans with all other organisms (all 5 P values = 0.0000). All other pairwise comparisons were insignificant (all 10 P values ≥ 0.1). After taking the averages of the 3 intervals, the order of the biofilm generation for different materials were as follows: Detax (average score: 1.56), Easyvac (1.67), Erkodent (1.78), Clear Tech (1.83), BD (2.28). Conclusions: As far as these 6 microorganisms are of concern, there might not be a significant overall difference among the clear retainer materials tested in this study. A significant overall increase was observed between the first and third days, which later did not significantly increase more until day 5. The Candida albicans biofilm was more intense than the tested 5 bacteria, which themselves showed rather similar growth patterns to each other. [ABSTRACT FROM AUTHOR]

Managing pelvic osteomyelitis (POM) in the setting of stage IV pressure injuries requires multidisciplinary evaluation as well as patient and caregiver engagement and is complicated by the lack of high-evidence data to guide best practices. In this review, we describe our approach to pressure injury and POM evaluation and management through multidisciplinary collaboration and highlight areas of future research that are necessary to enhance patient outcomes, reduce healthcare costs, and improve the quality of life of those affected by POM. [ABSTRACT FROM AUTHOR]

Helicobacter pylori is one of the most common bacterial pathogens worldwide and the main etiological agent of numerous gastric diseases. The frequency of multidrug resistance of H. pylori is growing and the leading factor related to this phenomenon is its ability to form biofilm. Therefore, the establishment of a proper model to study this structure is of critical need. In response to this, the aim of this original article is to validate conditions of the optimal biofilm development of H. pylori in monoculture and co-culture with a gastric cell line in media simulating human fluids. Using a set of culture-based and microscopic techniques, we proved that simulated transcellular fluid and simulated gastric fluid, when applied in appropriate concentrations, stimulate autoaggregation and biofilm formation of H. pylori. Additionally, using a co-culture system on semi-permeable membranes in media imitating the stomach environment, we were able to obtain a monolayer of a gastric cell line with H. pylori biofilm on its surface. We believe that the current model for H. pylori biofilm formation in monoculture and co-culture with gastric cells in media containing host-mimicking fluids will constitute a platform for the intensification of research on H. pylori biofilms in in vitro conditions that simulate the human body. [ABSTRACT FROM AUTHOR]

Acinetobacter baumannii is an opportunistic Gram-negative pathogen with exquisite survival capabilities under various environmental conditions and displays widespread resistance to common antibiotics. A. baumannii is a leading cause of nosocomial infections that result in high morbidity and mortality rates. Accordingly, when multidrug resistance rates surpass threshold levels, the percentage of A. baumannii clinical isolates surges. Research into A. baumannii has increased in the past decade, and multiple mechanisms of pathogenesis have been identified, including mechanisms underlying biofilm development, quorum sensing, exotoxin production, secretion system utilization, and more. To date, the two gold-standard strains used to investigate different aspects of A. baumannii pathogenesis include ATCC 17978 and ATCC 19606. Here, we report a comparative characterization study of three additional A. baumannii clinical isolates obtained from different infection types and derived from different anatomical regions of infected patients. The comparison of three clinical isolates in addition to the ATCC strains revealed that the hypervirulent bacteremia clinical isolate, known as HUMC1, employs a completely different mechanism of pathogenesis when compared to all its counterparts. In stark contrast to the other genetic variants, the hypervirulent HUMC1 isolate does not form biofilms, is antibiotic-susceptible, and has the capacity to reach higher levels of quorum compared to the other clinically relevant strains. Our data also reveal that HUMC1 does not shed endotoxin into the extracellular milieu, rather secretes the evolutionarily conserved, host-mimicking, Zonula occludens toxin (Zot). Taken together, our hypothesis that HUMC1 cells have the ability to reach higher levels of quorum and lack biofilm production and endotoxin shedding, accompanied by the substantial elaboration of Zot, suggests a novel mechanism of pathogenesis that appears to afford the hypervirulent pathogen with stealth-like capabilities when disseminating through the circulatory system in a state of bacteremia. [ABSTRACT FROM AUTHOR]

Background Bacterial vaginosis (BV) is difficult to eradicate due to BV biofilms protecting BV bacteria (Gardnerella, Prevotella, and other genera). With the growing understanding of biofilms, we systematically reviewed the current knowledge on the efficacy of anti-BV biofilm agents. Methods We searched literature in the Scopus, Medline, and Embase databases for empirical studies investigating substances for the treatment of BV biofilms or prevention of their recurrence and their efficacy and/or safety. Results Of 201 unique titles, 35 satisfied the inclusion criteria. Most studies (89%) reported on preclinical laboratory research on the efficacy of experimental antibiofilm agents (80%) rather than their safety. Over 50% were published within the past 5 years. Agents were classified into 7 groups: antibiotics, antiseptics, cationic peptides, enzymes, plant extracts, probiotics, and surfactants/surfactant components. Enzymes and probiotics were most commonly investigated. Earlier reports of antibiotics having anti-BV biofilm activity have not been confirmed. Some compounds from other classes demonstrated promising anti-BV biofilm efficacy in early studies. Conclusions Further research is anticipated on successful antibiofilm agents. If confirmed as effective and safe in human clinical trials, they may offer a breakthrough in BV treatment. With rising antibiotic resistance, antibiofilm agents will significantly improve the current standard of care for BV management. [ABSTRACT FROM AUTHOR]

Biofilm formation by Staphylococcus aureus is a major challenge in clinical settings due to its role in persistent infections. The AgrA protein, a key regulator in biofilm development, is a promising target for therapeutic intervention. This study investigates the antibiofilm potential of halogenated phenazine compounds by targeting AgrA and explores their molecular interactions to provide insights for drug development. We employed molecular docking, molecular dynamics simulations, and computational mutagenesis to evaluate the binding of halogenated phenazine compounds (C1 to C7, HP, and HP‐14) to AgrA. Binding free energy analysis was performed to assess the affinity of these compounds for the AgrA‐DNA complex. Additionally, the impact of these compounds on AgrA's structural conformation and salt bridge interactions was examined. The binding‐free energy analysis revealed that all compounds enhance binding affinity compared to the Apo form of AgrA, which has a ΔGbind of −80.75 kcal/mol. The strongest binding affinities were observed with compounds C7 (−113.84 kcal/mol), HP‐14 (−115.23 kcal/mol), and HP (−112.28 kcal/mol), highlighting their effectiveness. Molecular dynamics simulations demonstrated that these compounds bind at the hydrophobic cleft of AgrA, disrupting essential salt bridge interactions between His174‐Glu163 and His174‐Glu226. This disruption led to structural conformational changes and reduced DNA binding affinity, aligning with experimental findings on biofilm inhibition. The halogenated phenazine compounds effectively inhibit biofilm formation by targeting AgrA, disrupting its DNA‐binding function. The study supports the potential of these compounds as antibiofilm agents and provides a foundation for rational drug design targeting the AgrA‐DNA interaction. Future research should focus on further optimizing these lead compounds and exploring additional active sites on AgrA to develop novel treatments for biofilm‐associated infections. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) persist for long periods in the environment, causing adverse effects on aquatic and terrestrial ecosystems. The accumulation of MPs in various trophic levels mostly depends on weathering phenomena, their reduced dimensions and the improved bioavailability; this ultimately causes their ingestion by organisms living in different niches. The modern concern about MPs toxicity collides with the current unavailability of standardized and reliable methodologies to assess the risks associated with the exposure of organisms from different habitats. Hence, the identification and selection of appropriate biomonitors for MPs pollution risk assessment should focus on the identification of easy-to-implement assays, rapidly interpretable results (e.g., based on the MPs bioaccumulation capabilities in their tissues) and standardizable methodologies. The present review analyzed some emerging biomonitors exploited for MPs evaluation, selected and examined according to their potential use as specific biological indicators for diverse environments. The research was focused on plants, as biological models for airborne microfibers toxicity evaluation; mussels, as key organisms for the establishment of MPs accumulation in marine environments; land snails, representing emerging organisms selected for studies of MPs' impact on soil. Furthermore, recent findings evidenced the influence of microplastics on the composition of environmental microbiota, enhancing pathogenic biofilms formation, leading to increased water, soil, food, crops and waste contamination. Disposing of harmonized and validated methods to study MPs' impact on the environment, integrated with promising machine learning tools, might sensibly support the risk management strategies protecting human and animal health. [ABSTRACT FROM AUTHOR]

Biofilm-associated infections present a significant challenge in modern medicine, primarily due to their resilience and resistance to conventional treatments. These infections occur when bacteria form biofilms, protective layers formed by bacterial communities, which are notoriously resistant to traditional antibiotics on surfaces such as medical implants and biological surfaces, making eradication with standard antibiotics difficult. This resilience leads to persistent infections, imposing a substantial economic burden on healthcare systems. The urgency to find alternative treatments is critical as current methods are insufficient and costly. Innovative approaches, such as nanotechnology-based therapies, offer promising alternatives by targeting biofilms more effectively and reducing the need for invasive procedures. Nanocarriers hold significant promise in the fight against biofilm-associated infections. Nanocarriers can penetrate biofilms more effectively than conventional treatments, delivering higher concentrations of antibiotics or other antimicrobial agents precisely where they are needed. This targeted approach not only enhances the efficacy of treatments but also minimizes potential side effects. The development of nanocarrier-based therapies is crucial for overcoming the limitations of current treatments and ultimately improving patient outcomes and reducing the economic burden of biofilm-associated infections on healthcare systems. In this review, nanotechnology-based systems, their characteristics, limitations, and potential benefits are explored to address biofilms-related infections. Additionally, biofilm evaluation models and the tests necessary for the preclinical validation of these nanosystems to facilitate their clinical application are addressed. [ABSTRACT FROM AUTHOR]

The production of chitin generates wastewater containing high content of organic compounds, nutrients, and salinity, thus a biofilm system including anaerobic–anoxic–aerobic bioreactors was employed. This study aims to evaluate the performance of Stick-bed Biofix and Swim-bed Biofringe added to bioreactors as a biomass carrier in order to enhance biomass concentration. The results indicated that the organic removal has been insignificantly affected by high salinity, the removal efficiency was obtained at 95 ± 2% corresponding to a rate of 5.78 ± 1.10 kg COD/m3/d. Otherwise, the nitrogen removal rate was achieved at around 0.45 ± 0.17 kg N/m3/d and strongly decreased to 0.24 ± 0.10 kg N/m3/d under high salinity of 18,000 mg/L and a high loading rate of 1.03 ± 0.10 kg N/m3/d. Phosphorus removal was obtained at 0.032–0.057 kg P/m3/d and decreased by 1.5 times when the salinity is over 10,000 mg/L although the influent load was strongly reduced by pre-treatment. Besides, the biofilm system can also remove around 50% of calcium ions which causes high salinity in chitin production wastewater. [ABSTRACT FROM AUTHOR]

Biofilms are considered a basal resource with high nutritional quality in stream food webs, as periphytic algae are abundant of polyunsaturated fatty acids (PUFAs). PUFAs are essential for growth and reproduction of consumers who cannot or have very limited capacity to biosynthesize. Yet, how the nutritional quality based on PUFA of basal food sources changes with light intensity remains unclear. We conducted a manipulative experiment in mesocosms to explore the response and mechanisms of nutritional quality to shading, simulating riparian restoration. We found a significant increase in PUFA% (including arachidonic acid, ARA) under shading conditions. The increased PUFA is caused by the algal community succession from Cyanobacteria and Chlorophyta to Bacillariophyta which is abundant of PUFA (especially eicosapentaenoic acid, EPA; docosahexaenoic acid, DHA). On the other hand, shading increased PUFA via upregulating enzymes such as Δ12 desaturase (FAD2, EC:1.14.19.6) and 3-ketoacyl-CoA synthase (KCS, EC:2.3.1.199) in the biosynthesis of unsaturated fatty acid elongation pathways. Our findings imply that riparian reforestation by decreasing light intensity increases the nutritional quality of basal resources in streams, which may enhance transfer of good quality carbon to consumers in higher trophic levels through bottom-up effects. [ABSTRACT FROM AUTHOR]

Finding biomolecules in fossils is a challenging task due to their degradation over time from physical, chemical, and biological factors. The primary hypothesis for explaining the presence of biomolecules in fossilized bones tissues suggests their survival in the fossilization process. In contrast, some of these biomolecules could either derive from bacteria biofilm, thus without a direct relationship with the fossil record or could be an artifact from measurement procedures. Raman spectroscopy studies across various fossil ages and environments have detected multiple bands ranging from 1200 to 1800 cm−1 associative of organic compounds. However, the significance of these bands remains elusive. Our research aims to address this issue through a deep Raman spectroscopy investigation on Pleistocene teeth from Tayassu and Smilodon populator. These fossils were obtained from a well-preserved stratigraphic succession in Toca de Cima do Pilão cave, near the National Park of Serra da Capivara in semiarid Brazil. We propose two hypotheses to explain the presence of organic compounds related to 1200 to 1800 cm−1 Raman spectral range in fossil tissues: (i) these bands are biological signatures of preserved fossil biomolecules, or (ii) they are exogenous biological signatures associated with the bacterial biofilm formation during post-depositional processes. Our results align with the latter hypothesis, followed by biofilm degradation. However, the specific mechanisms involved in the natural biofilm degradation in fossil records remain unexplored in this study. In our case, the formation of biofilm on fossil bones is attributed to the oligotrophic conditions of the cave sediment matrix. We present a comprehensive model to elucidate the existence of biofilm on fossilized tissues, emphasizing the pivotal role of post-depositional processes, especially water action, in the cave environment. As the fossils were discovered in a cave setting, post-depositional processes significantly contribute to the formation of the biofilm matrix. Although our study provides insights into biofilm formation, further research is needed to delve into the specific mechanisms driving natural biofilm degradation in fossils. [ABSTRACT FROM AUTHOR]

The management of prosthetic joint infections is a complex and multilayered process that is additionally complicated by the formation of bacterial biofilm. Foreign material provides the ideal grounds for the development of an intricate matrix that hinders treatment and creates a difficult environment for antibiotics to act. Surgical intervention is often warranted but requires appropriate adjunctive therapy. Despite available guidelines, several aspects of antibiotic therapy with antibiofilm activity lack clear definition. Given the escalating challenges posed by antimicrobial resistance, extended treatment durations, and tolerance issues, it is essential to ensure that antimicrobials with antibiofilm activity are both potent and diverse. Evidence of biofilm-active drugs is highlighted, and alternatives to classical regimens are further discussed. [ABSTRACT FROM AUTHOR]

The study investigates the feasibility and performance of an indigenously designed algal-bacterial biofilm reactor (ABR) for treating graywater in rural areas. Focusing on both treatment efficacy and sustainability, the research explored two key areas: optimizing the ABR for efficient graywater treatment and evaluating the use of readily available, low-cost materials for its construction. To achieve this, ABR was optimized to handle the specific characteristics of rural graywater, including potential seasonal variations in nutrient concentrations. The optimized ABR's adaptability was rigorously assessed across various operational modes--batch, fed-batch, and continuous--demonstrating consistent removal efficiencies for key pollutants (COD, nitrate-nitrogen, total dissolved phosphate, and total ammoniacal nitrogen) under changing conditions. The fiber supportbased ABR demonstrated significant pollutant removal from rural graywater: 81% COD reduction, 49.5% nitrate-nitrogen (NO3-N), 88.46% total dissolved phosphate (TDP), and 83.42% total ammoniacal nitrogen (TAN) in batch mode. Moreover, there was almost complete removal of total suspended solids (from 142 mg L-1 on Day 1 to 0 mg L-1 on Day 6) and total coliform (39,000 CFU mL-1 to 30 CFU mL-1). Notably, these removal efficiencies remained consistent across fed-batch (and continuous operation modes), showcasing the ABR's adaptability. This adaptability facilitated a significant increase in treatment capacity, scaling from 3 L treated in batch mode (6 days) to 40 L in fed-batch mode (12 days) and a continuous treatment rate of 20 L per day. Further enhancing the sustainability of this approach, the study successfully employed readily available natural materials like bamboo pipes and sheets for constructing the ABR. This innovative design resulted in a remarkable increase in biomass productivity (9.8 g m-2 day-1) compared to polypropylene fiber-based reactors (4.5 g m-2 day-1) with enhanced treatment potential for all the parameters in batch mode (77.7% COD removal, 86% NO3-N removal, 81% TDP removal, 92% TAN removal, and 100% removal of total coliforms). This is the first reported algae-bacterial biofilm system using bamboo for wastewater treatment, promoting local resource utilization and a bio-based sustainable approach for rural graywater treatment. [ABSTRACT FROM AUTHOR]

Background: In the face of increasing antifungal resistance among Candida albicans biofilms, this study explores the efficacy of a combined treatment using Kangbainian lotion (KBN) and miconazole nitrate (MN) to address this challenge. Methods: Using UPLC-Q-TOF/MS Analysis for Identification of Active Compounds in KBN Lotion; FICI for synergy evaluation, XTT and ROS assays for biofilm viability and oxidative stress, fluorescence and confocal laser scanning microscopy (CLSM) for structural and viability analysis, and real-time fluorescence for gene expression. Conclusion: Our study indicates that the combined application of KBN and MN somewhat impacts the structural integrity of Candida albicans biofilms and affects the expression of several key genes involved in biofilm formation, including ALS1, ALS3, HWP1, HSP90, and CSH1. These preliminary findings suggest that there may be a synergistic effect between KBN and MN, potentially influencing not only the structural aspects of fungal biofilms but also involving the modulation of genetic pathways during their formation. [ABSTRACT FROM AUTHOR]

Background: Streptococcus mutans is studied for its acidogenic and aciduric characteristics, notably its biofilm formation in the presence of sucrose, toward its role in the caries process. Variations in both genotype and phenotype have been reported among clinical isolates of S. mutans. This study aimed to examine genotypic and phenotypic characteristics of S. mutans obtained from Thai children with varying caries statuses. Methods: We determined the presence of S. mutans and caries status in 395 children aged 3–4 years. From 325 children carrying S. mutans, we selected 90 with different caries statuses—caries-free (CF; n = 30), low severity of caries (LC; n = 30), or high severity of caries (HC; n = 30). Three isolates of S. mutans were taken from each child, thus, a total of 270 isolates were obtained. Multilocus sequence typing (MLST) was used to genotype the isolates and assess their clonal relationships. The properties, including biofilm formation, collagen binding, and acid production and tolerance were also evaluated. Results: Children with carious lesions showed a higher detection rate and number of S. mutans in saliva than those without caries. S. mutans from individuals with HC status showed the lowest biofilm formation ability, while this group had the highest detection rate of collagen-binding isolates. There was no difference in acid production or tolerance by caries status. Genotyping by MLST did not reveal any clone of S. mutans specific to CF status. This result remained even when we included MLST data from the open-access PubMLST database. MLST did identify clones containing only strains from caries-affected hosts, but tests of their phenotypic properties did not reveal any differences between S. mutans from these clones and clones that were from both caries-free and caries-affected children. Conclusions: The clonal relationships of S. mutans indicated by MLST were not associated with the status of dental caries in the host. [ABSTRACT FROM AUTHOR]

Background: In this study, individual methanogenic (anaerobic), granular biofilms were used as true community replicates to assess whole-microbial-community responses to environmental cues. The aggregates were sourced from a lab-scale, engineered, biological wastewater treatment system, were size-separated, and the largest granules were individually subjected to controlled environmental cues in micro-batch reactors (μBRs). Results: Individual granules were identical with respect to the structure of the active community based on cDNA analysis. Additionally, it was observed that the active microbial community of individual granules, at the depth of 16S rRNA gene sequencing, produced reproducible responses to environmental changes in pH, temperature, substrate, and trace-metal supplementation. We identified resilient and susceptible taxa associated with each environmental condition tested, as well as selected specialists, whose niche preferences span the entire trophic chain required for the complete anaerobic degradation of organic matter. Conclusions: We found that single anaerobic granules can be considered highly-replicated whole-ecosystems with potential usefulness for the field of microbial ecology. Additionally, they act as the smallest whole-community unit within the meta-community of an engineered bioreactor. When subjected to various environmental cues, anaerobic granules responded reproducibly allowing for rare or unique opportunities for high-throughput studies testing whole-community responses to a wide range of environmental conditions. [ABSTRACT FROM AUTHOR]

Despite extensive knowledge on phage resistance at bacterium level, the resistance of bacterial communities is still not well-understood. Given its ubiquity, it is essential to understand resistance at the community level. We performed quantitative investigations on the dynamics of phage infection in Klebsiella pneumoniae biofilms. We found that the biofilms quickly developed resistance and resumed growth. Instead of mutations, the resistance was caused by unassembled phage tail fibers released by the phage-lysed bacteria. The tail fibers degraded the bacterial capsule essential for infection and induced spreading of capsule loss in the biofilm, and tuning tail fiber and capsule levels altered the resistance. Latent infections sustained in the biofilm despite resistance, allowing stable phage-bacteria coexistence. Last, we showed that the resistance exposed vulnerabilities in the biofilm. Our findings indicate that phage lysate plays important roles in shaping phage-biofilm interactions and open more dimensions for the rational design of strategies to counter bacteria with phage. [ABSTRACT FROM AUTHOR]

Permanent artificial lighting systems in tourist underground environments promote the proliferation of photoautotrophic biofilms, commonly referred to as lampenflora, on damp rock and sediment surfaces. These green-colored biofilms play a key role in the alteration of native community biodiversity and the irreversible deterioration of colonized substrates. Comprehensive chemical or physical treatments to sustainably remove and control lampenflora are still lacking. This study employs an integrated approach to explore the biodiversity, eco-physiology and molecular composition of lampenflora from the Pertosa-Auletta Cave, in Italy. Reflectance analysis showed that photoautotrophic biofilms are able to absorb the totality of the visible spectrum, reflecting only the near-infrared light. This phenomenon results from the production of secondary pigments and the adaptability of these organisms to different metabolic regimes. The biofilm structure mainly comprises filamentous organisms intertwined with the underlying mineral layer, which promote structural alterations of the rock layer due to the biochemical attack of both prokaryotes (mostly represented by Brasilonema angustatum) and eukaryotes (Ephemerum spinulosum and Pseudostichococcus monallantoides), composing the community. Regardless of the corrosion processes, secondary CaCO3 minerals are also found in the biological matrix, which are probably biologically mediated. These findings provide valuable information for the sustainable control of lampenflora. [ABSTRACT FROM AUTHOR]

Natural products have been used since ancient times to treat various ailments and have been recognized for many years as a source of therapeutic agents and structural diversity. Plant-derived products have thus served as dietary components but also to maintain a state of wellbeing and health by preventing different diseases both of inflammatory and infective nature. Pentacyclic triterpenoids, particularly ursolic acid (UA) and oleanolic acid (OA), are well-studied natural products endowed with complex biological profiles. In this mini-review, we summarized the most advanced results on extraction methodologies and antimicrobial activity of UA and OA, focusing on their potential role as antimicrobic adjuvants, bacterial biofilm inhibitors and related mechanisms of action. This offers a theoretical basis and inspiration for further studies on their bioactivity mechanism. [ABSTRACT FROM AUTHOR]

Biofilms are a concern for spaceflight missions, given their propensity for biofouling systems and their potential threat to astronaut health. Herein, we describe a random positioning machine-based method for growing fluorescent protein-expressing streptococcal biofilms under simulated microgravity. Biofilms can be subsequently imaged by confocal microscopy without further manipulation, minimizing disruption of architecture. This methodology could be adaptable to other bacteria, potentially standardizing biofilm growth and study under simulated microgravity. [ABSTRACT FROM AUTHOR]

Background: Environmental reservoirs of antibiotic resistance pose a threat to human and animal health. Aquatic biofilms impacted by wastewater effluent (WW) are known environmental reservoirs for antibiotic resistance; however, the relative importance of biotic factors and abiotic factors from WW on the abundance of antibiotic resistance genes (ARGs) within aquatic biofilms remains unclear. Additionally, experimental evidence is limited within complex aquatic microbial communities as to whether genes bearing low sequence similarity to validated reference ARGs are functional as ARGs. Results: To disentangle the effects of abiotic and biotic factors on ARG abundances, natural biofilms were previously grown in flume systems with different proportions of stream water and either ultrafiltered or non-ultrafiltered WW. In this study, we conducted deep shotgun metagenomic sequencing of 75 biofilm, stream, and WW samples from these flume systems and compared the taxonomic and functional microbiome and resistome composition. Statistical analysis revealed an alignment of the resistome and microbiome composition and a significant association with experimental treatment. Several ARG classes exhibited an increase in normalized metagenomic abundances in biofilms grown with increasing percentages of non-ultrafiltered WW. In contrast, sulfonamide and extended-spectrum beta-lactamase ARGs showed greater abundances in biofilms grown in ultrafiltered WW compared to non-ultrafiltered WW. Overall, our results pointed toward the dominance of biotic factors over abiotic factors in determining ARG abundances in WW-impacted stream biofilms and suggested gene family-specific mechanisms for ARGs that exhibited divergent abundance patterns. To investigate one of these specific ARG families experimentally, we biochemically characterized a new beta-lactamase from the Planctomycetota (Phycisphaeraceae). This beta-lactamase displayed activity in the cleavage of cephalosporin analog despite sharing a low sequence identity with known ARGs. Conclusions: This discovery of a functional planctomycete beta-lactamase ARG is noteworthy, not only because it was the first beta-lactamase to be biochemically characterized from this phylum, but also because it was not detected by standard homology-based ARG tools. In summary, this study conducted a metagenomic analysis of the relative importance of biotic and abiotic factors in the context of WW discharge and their impact on both known and new ARGs in aquatic biofilms. DkJa1T-YWptaXXeH_hsDtB Video Abstract [ABSTRACT FROM AUTHOR]

The gut microbiota is vital to human health, and their biofilms significantly impact intestinal immunity and the maintenance of microbial balance. Certain pathogens, however, can employ biofilms to elude identification by the immune system and medical therapy, resulting in intestinal diseases. The biofilm is formed by extracellular polymorphic substances (EPS), which shield microbial pathogens from the host immune system and enhance its antimicrobial resistance. Therefore, investigating the impact of extracellular polysaccharides released by pathogens that form biofilms on virulence and defence mechanisms is crucial. In this review, we provide a comprehensive overview of current pathogenic biofilm research, deal with the role of extracellular polymers in the formation and maintenance of pathogenic biofilm, and elaborate different prevention and treatment strategies to provide an innovative approach to the treatment of intestinal pathogen-based diseases. [ABSTRACT FROM AUTHOR]

Importance: Staphylococcus aureus frequently colonizes the skin and nose of patients with atopic dermatitis (AD), a disease associated with skin barrier dysfunction and chronic cutaneous inflammation. Published genomic studies on AD-associated S. aureus in pediatric populations in sub-Saharan Africa are limited. Objectives: To investigate the phenotypic and genomic diversity of S. aureus in children with and without AD during early childhood. Data, setting and participants: A cross-sectional study of 220 children (aged 9-38 months) with AD (cases) and without AD (controls) from Cape Town and Umtata, South Africa. Main outcomes and measures: S. aureus phenotypic and genomic diversity were investigated using whole-genome sequencing, antibiotic susceptibility testing and biofilm microtiter assay. Results: Of the 124 S. aureus isolates recovered from 220 children, 96 isolates (79 cases and 17 controls) with high-quality sequences were analyzed. Isolates from cases showed greater phenotypic resistance to gentamicin (10%), rifampicin (4%), chloramphenicol (4%), and exhibited multidrug resistance (9%) than in controls. Furthermore, the isolates from cases formed stronger biofilms than those from controls (76% vs. 35%, p = 0.001), but showed no dominance of any virulence factor gene or mobile genetic elements. There was no significant difference in the distribution of immune evasion cluster types between cases and controls. However, IEC type G was identified only among cases. Conclusion and relevance: AD-associated S. aureus has phenotypic and genetic features that are important for successful pathogenic colonization and survival. Further studies are needed to assess the pathological implications of colonization of various S. aureus lineages in vivo to elucidate their pathological contribution to AD pathogenesis and pathophysiology. [ABSTRACT FROM AUTHOR]

A three‐dimensional tubular fabric known as "vermiform microstructure" in Phanerozoic and Neoproterozoic carbonate microbialites has been hypothesized to represent the body fossil of nonspicular keratose demosponges. If correct, this interpretation extends the sponge body fossil record and origin of animals to ~890 Ma. However, the veracity of the keratose sponge interpretation for vermiform microstructure remains in question, and the origin of the tubular fabric is enigmatic. Here we compare exceptionally well‐preserved microbialite textures from the Upper Triassic to channel networks created by modern microbial biofilms. We demonstrate that anastomosing channel networks of similar size and geometries are produced by microbial biofilms in the absence of sponges, suggesting the origin for vermiform microstructure in ancient carbonates is not unique to sponges and perhaps best interpreted conservatively as likely microbial in origin. We present a taphonomic model of early biofilm lithification in seawater with anomalously high carbonate saturation necessary to preserve delicate microbial textures. This work has implications for the understanding of three‐dimensional biofilm architecture that goes beyond the current micro‐scale observations available from living biofilm experiments and suggests that biofilm channel networks have an extensive fossil record. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa can efficiently adapt to changing environmental conditions due to its ubiquitous nature, intrinsic/acquired/adaptive resistance mechanisms, high metabolic versatility, and the production of numerous virulence factors. As a result, P. aeruginosa becomes an opportunistic pathogen, causing chronic infection in the lungs and several organs of patients suffering from cystic fibrosis. Biofilm established by P. aeruginosa in host tissues and medical device surfaces has been identified as a major obstruction to antimicrobial therapy. P. aeruginosa is very likely to be closely associated with the various microorganisms in the host tissues or organs in a pathogenic or nonpathogenic behavior. Aside from host-derived molecules, other beneficial and pathogenic microorganisms produce a diverse range of secondary metabolites that either directly or indirectly favor the persistence of P. aeruginosa. Thus, it is critical to understand how P. aeruginosa interacts with different molecules and ions in the host and abiotic environment to produce extracellular polymeric substances and virulence factors. Thus, the current review discusses how various natural and synthetic molecules in the environment induce biofilm formation and the production of multiple virulence factors. [ABSTRACT FROM AUTHOR]

The characterization of surface microbiota living in biofilms within livestock buildings has been relatively unexplored, despite its potential impact on animal health. To enhance our understanding of these microbial communities, we characterized 11 spore-forming strains isolated from two commercial broiler chicken farms. Sequencing of the strains revealed them to belong to three species Bacillus velezensis, Bacillus subtilis, and Bacillus licheniformis. Genomic analysis revealed the presence of antimicrobial resistance genes and genes associated with antimicrobial secretion specific to each species. We conducted a comprehensive characterization of the biofilm formed by these strains under various conditions, and we revealed significant structural heterogeneity across the different strains. A macro-colony interaction model was employed to assess the compatibility of these strains to coexist in mixed biofilms. We identified highly competitive B. velezensis strains, which cannot coexist with other Bacillus spp. Using confocal laser scanning microscopy along with a specific dye for extracellular DNA, we uncovered the importance of extracellular DNA for the formation of B. licheniformis biofilms. Altogether, the results highlight the heterogeneity in both genome and biofilm structure among Bacillus spp. isolated from biofilms present within livestock buildings. [ABSTRACT FROM AUTHOR]

Campylobacter jejuni plays a significant role in human health, food production, and veterinary practice. Biofilm formation is a likely mechanism explaining the survival of C. jejuni in seemingly unfavourable environments, but the underlying mechanisms are poorly understood. We propose a mathematical model to unify various observations regarding C. jejuni biofilm formation. Specifically, we present a cellular automaton with stochastic dynamics that describes both the probability of biofilm initiation and its subsequent growth. Our model incorporates fundamental processes such as cell rearrangement, diffusion of chemical compounds, accumulation of extracellular material, cell growth, lysis, and deactivation due to nutrient scarcity. The model predicts an optimal nutrient concentration that enhances population survival, revealing a trade-off where higher nutrient levels may harm individual cells but benefit the overall population. Our results suggest that the lower biofilm accumulation observed experimentally in aerobic conditions compared to microaerobic conditions may be due to a reduced surface invasion probability of individual cells. However, cells that do manage to invade can generate microcolonies of a similar size under both aerobic and microaerobic conditions. These findings provide new insights into the survival probability and size of C. jejuni biofilms, suggesting potential targets for controlling its biofilm formation in various environments. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus and coagulase-negative staphylococci account for about 80% of infections associated with medical devices and are associated with increased virulence due to their ability to form biofilm. In this study, we aimed to construct a comprehensive reference map followed by significant pathway analysis in the proteome of S. aureus biofilm grown for 3 days compared with 24 h of planktonic culture using a high-resolution Tandem Mass Tag (TMT)-based MS. We identified proteins associated with secondary metabolites, ABC transporters, biosynthesis of amino acids, and response to stress, and amino sugar and nucleotide sugar metabolism were significantly upregulated in 3-day biofilm. In contrast, proteins associated with virulence factors, microbial metabolism in diverse environments, secondary metabolites, translation, and energy metabolism were significantly downregulated. GO functional annotation indicated that more proteins are involved in metabolic processes, catalytic activity, and binding in biofilm, respectively. Among the significantly dysregulated proteins, hyaluronidase (hysA) in conjunction with chitinase may play a significant role in the elimination and/or prevention of biofilm development. This study advances the understanding of the S. aureus subproteome, identifying potential pathways significant to biofilm biology. The insights gained may aid in developing new therapeutic strategies, including antibiofilm agents, for treating biofilm-related infections associated with implantable medical devices. [ABSTRACT FROM AUTHOR]

Biofilms are accumulations of microorganisms in an extracellular polymeric substance matrix which are composed of polysaccharides, proteins, lipids, and nucleic acids. Many bacteria can switch between a planktonic form and a biofilm form. The planktonic bacteria have relatively high cell growth and reproduction rates and have a reduced likelihood of survival but can adapt to occupy new habitats. The biofilm state appears to be a natural and predominant state of bacteria. The need for the formation of bacterial biofilm is that it enhances the tolerance of bacteria to harsh environmental conditions, thereby allowing bacteria to avoid being washed away by water flow or the bloodstream by simply attaching to a surface or tissue, and the EPS matrix protects bacteria cells, in deeper layers, against antimicrobial agents, probably by limiting the diffusion of these agents. Biofilm formation steps are initial contact/attachment to the surface, followed by micro-colony formation, maturation and formation of the architecture of the biofilm, and finally detachment/dispersion of the biofilm. Once formed, biofilm restricts bacterial mobility and increases cell density. Secretions of autoinducers into the environment are critical for cross-signaling between bacteria. This cross-talk is called quorum sensing (QS). Quorum sensing is a cell–cell communication mechanism between bacteria that allows specific processes to be controlled, such as biofilm formation and virulence factor expression. Bacterial quorum sensing signaling mainly consists of acyl-homoserine lactones (produced by Gram-negatives), autoinducing peptides (produced by Gram-positives), and autoinducer-2 (produced by both Gram-negatives and Gram-positives). Therefore, this review is aimed at how bacterial biofilms work and are formed. [ABSTRACT FROM AUTHOR]

Aim Bacterial biofilms can form on surfaces in hospitals, clinics, farms, and food processing plants, representing a possible source of infections and cross-contamination. This study investigates the effectiveness of new commercial wipes against Staphylococcus aureus and Pseudomonas aeruginosa biofilms (early attachment and formed biofilms), assessing LH SALVIETTE wipes (Lombarda H S.r.l.) potential for controlling biofilm formation. Methods and results The wipes efficacy was studied against the early attachment phase and formed biofilm of S. aureus ATCC 6538 and P. aeruginosa ATCC 15442 on a polyvinyl chloride (PVC) surface, following a modified standard test EN 16615:2015, measuring Log10 reduction and cell viability using live/dead staining. It was also evaluated the wipes anti-adhesive activity over time (3 h, 2 4h), calculating CFU.mL−1 reduction. Data were analyzed using t -student test. The wipes significantly reduced both early phase and formed S. aureus biofilm, preventing dispersion on PVC surfaces. Live/dead imaging showed bacterial cluster disaggregation and killing action. The bacterial adhesive capability decreased after short-time treatment (3 h) with the wipes compared to 24 h. Conclusions Results demonstrated decreased bacterial count on PVC surface both for early attachment phase and formed biofilms, also preventing the bacterial biofilm dispersion. [ABSTRACT FROM AUTHOR]

Green synthesis of silver nanoparticles using Moringa oleifera (AgNPs/MO) was carried out to produce nanoscale antifungal agents which are used as photosensitizing agents in photoantimicrobial therapy. This study focused on investigating the potential of AgNPs/MO producing some toxic radical compounds that inhibit the growth of Candida albicans biofilms. The inhibition mechanism uses the principle of photoinactivation treatment which combines a photosensitizer with an LED light source at a power of 100 mW for 60 - 300 s of exposure. Quantitative data analyzed were the number of viable cells and radical compounds, formed by malondialdehyde (MDA) level. It is investigated through staining the XTT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) and TBARS (Thiobarbituric Acid Reactive Substances). The results show that the maximum wavelength of AgNPs is 440 nm while the Moringa oleifera has 2 peaks at 425 and 635 nm. The maximum effect occurred in the group of photosensitizer AgNPs/MO combined LED with percentage inactivation about 76.80 % for blue LEDs and 76.20 % for red LEDs. The group of LED irradiation without photosensitizer obtained about 51.85 % for blue LEDs and 50.04 % for red LEDs. The MDA level group of AgNPs/MO combined LED also produced MDA levels of 1.772 nmol/mL for blue LED and 1.617 nmol/mL for red LED. Meanwhile, the application of photoantimicrobial using only LEDs produced MDA levels of only 1.353 nmol/mL for blue LEDs and 1.347 nmol/mL for red LEDs. This research has shown that the green synthesis of AgNPs/MO has a good potential to inhibit the growth of Candida albicans biofilms as a photosensitizer agent. [ABSTRACT FROM AUTHOR]

Antibiotics like colistin can save patients infected with carbapenem-resistant Pseudomonas aeruginosa. However, patients can succumb to such infections even if they undergo colistin therapy. This prompted us to investigate the probable antimicrobial resistance mechanisms and virulence determinants involved in colistin- and carbapenem-resistant P. aeruginosa (CCRPA). Of the 448 P. aeruginosa clinical strains, 19 isolates were resistant to both colistin and carbapenem. Carbapenemases and efflux pump encoding genes were assessed by multiplex PCR and qPCR, respectively. blaVIM was detected among six CCRPA isolates and blaIMP in one strain. The expression levels of pmrA and phoP, as well as pmrB genes and their association with colistin resistance, were assessed by qPCR and semi-quantitate PCR, respectively. pmrA and phoP genes were significantly enhanced in three and nine CCRPA isolates, respectively. We also phenotypically evaluated biofilms, pyocyanin, and alginate production among CCRPA strains. Alginate production was observed in 15 isolates, followed by biofilm (n = 8) and pyocyanin (n = 5). Our results highlighted the coexistence of colistin and carbapenem resistance and biofilm formation among clinical isolates of CCRPA. Further studies are required to trace the source and the origin of colistin and carbapenem resistance in this specific environment. [ABSTRACT FROM AUTHOR]

Recently, studies suggest that the protective effects of Lactobacillus within the female reproductive tract may be partly due to their ability to form biofilms. This study aims to explore the possibility that Lactobacillus can produce key mediators to further bolster the survival of biofilms in human vaginal microbiomes. Three bacterial species, namely, Lactobacillus gasseri, L. crispatus, and L. jensenii, sourced from human female subjects were used to carry out experiments examining the growth of biofilms using a microfermenter system. The bacteria were used to inoculate a glass rod spatula which was subsequently transferred to the microfermenter system. The resulting biofilm growing on the glass spatula was harvested in media and stored in a −80 °C freezer for gas chromatography–mass spectroscopy analysis. We found that quorum sensing compounds, acyl homoserine lactones (AHLs), were detected in the biofilm of L. crispatus and L. jensenii, but none were detected in L. gasseri. The biofilm produced by L. crispatus and L. jensenii was much higher in quantity than the biofilm produced by L. gasseri. Aside from oligopeptides quorum sensing, lactobacilli were found to also have AHL compounds that may help them produce more biofilms and improve the survival and growth of their bacterial communities in the female genital area. [ABSTRACT FROM AUTHOR]

Vibrio cholerae, a facultative human pathogen and causative agent of the severe diarrheal disease cholera, transits between the human intestinal tract and aquatic reservoirs. Like other bacterial species, V. cholerae continuously releases bacterial extracellular vesicles (BEVs) from its surface, which have been recently characterised for their role during in vivo colonisation. However, between epidemic outbreaks, V. cholerae persists in the biofilm mode for extended periods in aquatic reservoirs, which enhances environmental fitness and host transition. In this study, we investigated the effect of V. cholerae BEVs on biofilm formation, a critical feature for ex vivo survival. In contrast to BEVs from planktonic cultures, our results show that physiological concentrations of BEVs from dynamic biofilm cultures facilitate V. cholerae biofilm formation, which could be linked to a proteinaceous factor. Comparative proteomic analyses of planktonic‐ and biofilm‐derived BEVs identified a previously uncharacterised outer membrane protein as an abundant component of dynamic biofilm‐derived BEVs, which was found to be responsible for the BEV‐dependent enhancement of biofilm production. Consequently, this protein was named outer membrane‐associated biofilm facilitating protein A (ObfA). Comprehensive molecular studies unravelled ObfA as a negative modulator of HapR activity. HapR is a key transcriptional regulator of the V. cholerae quorum sensing (QS) cascade acting as a potent repressor of biofilm formation and virulence. Consistently, obfA mutants not only exhibited reduced biofilm production but also reduced colonisation fitness. Surprisingly, our results demonstrate that ObfA does not affect HapR through the canonical QS system but via the Csr‐cascade altering the expression of the small regulatory RNAs CsrC and CsrD. In summary, this study elucidates a novel intraspecies BEV‐based communication in V. cholerae that influences biofilm formation and colonisation fitness via a new regulatory pathway involving HapR, Csr‐cascade and the BEV‐associated protein ObfA. [ABSTRACT FROM AUTHOR]

This study investigated the phylotypes, biofilm formation abilities, antibiotic resistance of enteropathogenic Escherichia coli (EPEC) isolates from cats with diarrhea. From 37 diarrheal cats, 28 E. coli isolates were obtained using conventional methods. Pathotypes and phylotypes were determined via PCR, biofilm formation potential via Congo Red Agar, and resistance profiles against eight antibiotics were examined using the disk diffusion method, evaluated according to the Clinical and Laboratory Standards Institute (CLSI). Chi-square tests assessed relationships between phylogenetic groups, biofilm formation, and MDR statuses. The results were considered statically significant at a 95% confidence interval and significance level of P<0.05. Pathotyping studies showed that 46% (13 isolates) of the isolates were EPEC. 93% of isolates were phylotyped. Seven phylotypes were detected: B2 (22%), C (18%), B1 (18%), D (14%), A (11%), E (7%) and F (3%). Of the isolates 39% formed biofilms and 86% were MDR. No significant association was found between pathotype and biofilm formation or MDR. However, a significant relationship was noted between pathotype EPEC and phylogenetic group B2. The correlation between EPEC pathotype and phylotype B2 in diarrheic cats suggests high pathogenic potential. Multidrug resistance, even in non-biofilm forming isolates, complicates treatment and poses public health risks, underscoring the need for detailed evaluation of E. coli diversity and zoonotic pathogens. [ABSTRACT FROM AUTHOR]

Background: The presence of contamination and microorganisms at any stage of processing renders a method unsafe, leading to a high risk of cross-transmission and cross-infection. Objective: The objective of this study was to assess the cleaning quality of aspirator instruments used in neurosurgical procedures. Methods: The experimental study was conducted at the materials and sterilization center, as well as the microbiology laboratory, of a philanthropic hospital in Brazil. A study protocol was implemented, which involved the analysis of 10 samples of Yasargil aspirators with varying dimensions. The samples were subjected to protein tests to detect the presence of organic matter and microbiological analysis. Descriptive statistics were used to analyze the data. Results: The results indicated that 40% of the instruments tested positive for protein after manual cleaning. Furthermore, after automated cleaning, samples showed an increased microbiological load, with Escherichia coli accounting for 20% and Klebsiella aerogenes for 10% of the identified microorganisms. Conclusion: This study provides evidence of failures in the cleaning process of healthcare products and highlights the presence of biofilm in the pipes, thereby compromising the drinking water quality standard. [ABSTRACT FROM AUTHOR]

Micropollutants are increasingly prevalent in the aquatic environment. A major part of these originates from wastewater treatment plants since traditional treatment technologies do not remove micropollutants sufficiently. Moving bed biofilm reactors (MBBRs), however, have been shown to aid in micropollutant removal when applied to conventional wastewater treatment as a polishing step. Here, we used Total RNA sequencing to investigate both the active microbial community and functional dynamics of MBBR biofilms when these were exposed to increasing micropollutant concentrations over time. Concurrently, we conducted batch culture experiments using biofilm carriers from the MBBRs to assess micropollutant degradation potential. Our study showed that biofilm eukaryotes, in particular protozoa, were negatively influenced by micropollutant exposure, in contrast to prokaryotes that increased in relative abundance. Further, we found several functional genes that were differentially expressed between the MBBR with added micropollutants and the control. These include genes involved in aromatic and xenobiotic compound degradation. Moreover, the biofilm carrier batch experiment showed vastly different alterations in benzotriazole and diclofenac degradation following the increased micropollutant concentrations in the MBBR. Ultimately, this study provides essential insights into the microbial community and functional dynamics of MBBRs and how an increased load of micropollutants influences these dynamics. [ABSTRACT FROM AUTHOR]

The aquatic γ-proteobacterium Shewanella oneidensis is able to form two types of biofilms: a floating biofilm at the air–liquid interface (pellicle) and a solid surface-associated biofilm (SSA-biofilm). S. oneidensis possesses the Bpf system, which is orthologous to the Lap system first described in Pseudomonas fluorescens. In the Lap systems, the retention of a large adhesin (LapA) at the cell surface is controlled by LapD, a c-di-GMP effector protein, and LapG, a periplasmic protease targeting LapA. Here, we showed that the Bpf system is mandatory for pellicle biogenesis, but not for SSA-biofilm formation, indicating that the role of Bpf is somewhat different from that of Lap. The BpfD protein was then proved to bind c-di-GMP via its degenerated EAL domain, thus acting as a c-di-GMP effector protein like its counterpart LapD. In accordance with its key role in pellicle formation, BpfD was found to interact with two diguanylate cyclases, PdgA and PdgB, previously identified as involved in pellicle formation. Finally, BpfD was shown to interact with CheY3, the response regulator controlling both chemotaxis and biofilm formation. Altogether, these results indicate that biofilm formation in S. oneidensis is under the control of a large c-di-GMP network. [ABSTRACT FROM AUTHOR]

Background: Periodontal tissue damage is mainly caused by the active form of collagenolytic matrix metalloproteinase-8, aMMP-8, the concentration of which in the mouth rinse can be measured with a mouth rinse chairside-test. The mouth rinse chair side test can be used to identify adolescents with a risk of periodontitis. Methods: The data were collected at the Kotka Health Centre (2004–2005, N = 501 and 2014–2015, N = 47) and at the Hämeenlinna Health Centre (2017–2018, N = 125) consisting of adolescents aged 14–17. They underwent a complete periodontal examination, and some were subjected to the aMMP-8-test. Results: We identified bacterial plaques in combination with increased bleeding on probing (BOP), elevated aMMP-8 concentration, smoking and male sex as the main risk factors for initial periodontitis. Approximately 10% of adolescents had subclinical periodontitis, they were not periodontally healthy, but also not sick. They may not develop periodontitis, but they are at the risk. The aMMP-8 test positivity had a stronger association with initial periodontitis than BOP. Conclusions: In addition to identifying risk factors, these adolescents need individual prevention and, if necessary, early treatment. For the periodontal health biomarker aMMP-8, test negativity ([-], ≤20 ng/mL) should be sought. [ABSTRACT FROM AUTHOR]

Background: Fusobacterium nucleatum (F. nucleatum) is an integral component of supra‐ and subgingival biofilms, especially more prevalent in subgingival areas during both periodontal health and disease. Aims: In this review, we explore the physical, metabolic, and genetic interactions that influence the role of F. nucleatum in the formation of mixed oral biofilms. The role of F. nucleatum in antibiotic resistance in oral biofilms was discussed and some therapeutic strategies were proposed. Methods: PubMed, Scopus, Google Scholar, and the Web of Science were extensively searched for English‐language reports. Results: F. nucleatum‐derived proteins such as RadD, Fap2, FomA, and CmpA are involved in direct interactions contributing to biofilm formation, while autoinducer‐2 and putrescine are involved in metabolic interactions. Both groups are essential for the formation and persistence of oral biofilms. This study highlights the clinical relevance of targeted interactions of F. nucleatum in supra‐ and subgingival oral biofilms. Conclusions: By focusing on these interactions, researchers and clinicians can develop more effective strategies to prevent biofilm‐related disease and reduce the spread of antibiotic resistance. Further research in this area is warranted to explore the potential therapeutic interventions that can be derived from understanding the interactions of F. nucleatum in oral biofilm dynamics. [ABSTRACT FROM AUTHOR]

We continue our review of on punctal stenosis by providing a detailed discussion of management modalities, their complications, and outcomes. There is a significant change in the understanding of punctal and peripunctal anatomy, puncto-canalicular junction, and the lacrimal pump mechanisms. While the snip punctoplasty procedures are still practiced, there is an increasing trend toward nonincisional procedures. The nonincisional procedures in select cases appear to be equally effective as the incisional ones. Although simple to use, punctal plugs never became the mainstay of treatment because of design issues and the inability to address the coexisting canalicular stenosis. Placing stents only in the lower punctum in cases of upper and lower punctal stenosis should be discouraged, and management needs to address punctal stenosis and not which punctum is involved. Several types of stents are used in the management of punctal stenosis, mostly based on surgeon's preference. The benefits of adjuvant mitomycin C are uncertain. In view of literature on how stent biofilms can themselves cause chronic inflammation, placing them for prolonged periods should be reviewed and debated. Enhanced understanding of the molecular pathogenesis of punctal stenosis and addressing the current controversies in management would help standardize the therapeutic interventions available in the lacrimal armamentarium. [ABSTRACT FROM AUTHOR]

• IAC significantly affects the nitrogen removal performance of the PN/A system. • Rate-limiting step of mature PN/A biofilms was independent of IAC. • IAC does not affect the ecological niche differentiation of Ca. Brocadia and Ca. Jettenia. • Enhanced nitrogen removal performance via IAC regulation. One-stage partial nitrification coupled with anammox (PN/A) technology effectively reduces the energy consumption of a biological nitrogen removal system. Inhibiting nitrite-oxidizing bacteria (NOB) is essential for this technology to maintain efficient nitrogen removal performance. Initial ammonium concentration (IAC) affects the degree of inhibited NOB. In this study, the effect of the IAC on a PN/A biofilm was investigated in a moving bed biofilm reactor. The results showed that nitrogen removal efficiency decreased from 82.49% ± 1.90% to 64.57% ± 3.96% after the IAC was reduced from 60 to 20 mg N/L, while the nitrate production ratio increased from 13.87% ± 0.90% to 26.50% ± 3.76%. NOB activity increased to 1,133.86 mg N/m2/day after the IAC decreased, approximately 4-fold, indicating that the IAC plays an important inhibitory role in NOB. The rate-limiting step in the mature biofilm of the PN/A system is the nitritation process and is not shifted by the IAC. The analysis of the microbial community structure in the biofilm indicates that the IAC was the dominant factor in changes in community structure. Ca. Brocadia and Ca. Jettenia were the main anammox bacteria, and Nitrosomonas and Nitrospira were the main AOB and NOB, respectively. IAC did not affect the difference in growth between Ca. Brocadia and Ca. Jettenia. Thus, modulating the IAC promoted the PN/A process with efficient nitrogen removal performance at medium to low ammonium concentrations. [Display omitted] [ABSTRACT FROM AUTHOR]