Search

Diverse surgical approaches, such as resective, reconstructive, and combined therapy, have been proposed for peri-implantitis treatment. A resective surgical approach with an adjunctive modified implantoplasty refers to the modification of the implant body into a constricted area to mimic a "waist" silhouette. This modified technique forms an adequate concave smooth area that may favor the outcomes of resective surgical therapy for soft tissue adaptation, biofilm control, and possible peri-implant bone gain over the long term. The present case series aimed to exhibit the long-term clinical and radiographic outcomes of resective surgery with adjunctive implantoplasty over a 6- to 11-year follow-up. Four patients presenting four implants (one per patient) diagnosed with peri-implantitis (according to an established case definition) were included in the present case series. Patients underwent resective surgery, a modified implantoplasty approach, and implant surface decontamination. After surgical therapy, clinical and radiographic outcomes such as bleeding on probing (BoP), suppuration on probing (SoP), probing depth (PD), marginal recession (MR), modified plaque index (mPI), and marginal bone levels (MBLs) were recorded over a long-term follow-up period. Over the 6- to 11-year follow-up, mean BoP, PD, and SoP scores amounted to 17% ± 24%, 3.2 ± 0.66 mm, and 0%, respectively. Mean BoP, PD, and SoP scores were reduced by 67% ± 24%, 2.5 ± 1.26 mm, and 100%, respectively. Radiographic analysis revealed a mean radiographic bone gain of 3.1 ± 1.84 mm. Peri-implant marginal bone loss surface area decreased by 5.7 ± 3.77 mm2 over the long-term follow-up. Resective therapy with adjunctive implantoplasty promoted favorable clinical and radiographic outcomes at treated peri-implantitis sites over a long-term period. [ABSTRACT FROM AUTHOR]

Plastic waste, especially positively buoyant polymers known as polyolefins, are a major component of floating debris in the marine environment. While plastic colonisation by marine microbes is well documented from environmental samples, the succession of marine microbial community structure over longer time scales (> > 1 month) and across different types and shapes of plastic debris is less certain. We analysed 16S rRNA and 18S rRNA amplicon gene sequences from biofilms on polyolefin debris floating in a flow-through seawater tank in Hawaii to assess differences in microbial succession across the plastic types of polypropylene (PP) and both high-density polyethylene (HDPE) and low-density polyethylene (LDPE) made of different plastic shapes (rod, film and cube) under the same environmental conditions for 1 year. Regardless of type or shape, all plastic debris were dominated by the eukaryotic diatom Nitzschia, and only plastic type was significantly important for bacterial community structure over time (p = 0.005). PE plastics had higher differential abundance when compared to PP for 20 bacterial and eight eukaryotic taxa, including the known plastic degrading bacterial taxon Hyphomonas (p = 0.01). Results from our study provide empirical evidence that plastic type may be more important for bacterial than eukaryotic microbial community succession on polyolefin pollution under similar conditions.

Purpose: This study aimed to investigate the inhibitory effect of a PRG Barrier Coat on biofilm formation and structure by Streptococcus mutans and propose an effective method for preventing dental caries. Materials and Methods: Streptococcus mutans MT8148 biofilms were obtained from hydroxyapatite disks with and without a PRG Barrier Coat. Scanning electron microscopy (SEM) was used to observe the 12- and 24-h-cultured biofilms, while reverse-transcription polymerase chain reaction (qRT-PCR) was used to quantify caries-related genes. Biofilm adhesion assessments were performed on glass. Statistical analysis was performed using a two-sample t-test. Results: A statistically significant difference in Streptococcus mutans biofilm adhesion rate was observed between the control and PRG Barrier Coat-coated samples (p < 0.01). However, there was no statistically significant difference in total bacterial count or biofilm volume (p > 0.05). SEM revealed that the PRG Barrier Coat inhibited biofilm formation by Streptococcus mutans. Real-time RT-PCR revealed that the material restricted the expression of genes associated with caries-related biofilm formation. However, the suppression of gtfD and dexB differed from that of other genes. Conclusion: PRG Barrier Coat suppressed biofilm formation by Streptococcus mutans by inhibiting the expression of insoluble glucan synthase, which is associated with primary biofilm formation. The material also affected gene expression and altered the biofilm structure. Tooth surface-coating materials, such as PRG Barrier Coat, may improve caries prevention in dental practice. [ABSTRACT FROM AUTHOR]

The aim of this morphometric study was to precisely determine the 3D characteristics of the root complex of the posterior dentition. Extracted and well-preserved permanent posterior teeth were included in this analysis and grouped based on tooth type and arch location. All teeth were digitally scanned. Morphologic and dimensional features of the root complex were assessed, including length and surface area of the root trunk and individual roots, width of root concavities (RC), and furcation entrance, when present. A total of 240 posterior teeth comprised the study sample. The root complex of multirooted maxillary first premolars presented with a long root trunk (10.49 mm), representing 65.52% of the surface area, and two short roots comprising the remaining 34.8% of the surface area. Root trunks of mandibular molars were an average of 0.8 mm shorter than their maxillary counterparts. Class III furcation involvement is expected in all maxillary and mandibular molars, as well as multirooted maxillary first premolars, after 4.80 mm and 10.49 mm of clinical attachment loss, respectively. RCs were a common finding among the evaluated dentitions. The root complex morphology varies among the maxillary and mandibular posterior dentition. RCs are highly prevalent in both maxillary and mandibular dentition. The findings derived from this study can be utilized in daily clinical practice for the adequate management of posterior dentition and serve as a reference for future investigations in dental anatomy and digital technology. Also, these findings can guide the industry into creating and redefining tools that adequately adapt to the anatomical characteristics and variations of the specific tooth type. [ABSTRACT FROM AUTHOR]

UNLABELLED: Motility promotes biofilm initiation during the early steps of this process: microbial surface association and attachment. Motility is controlled in part by chemotaxis signaling, so it seems reasonable that chemotaxis may also affect biofilm formation. There is a gap, however, in our understanding of the interactions between chemotaxis and biofilm formation, partly because most studies analyzed the phenotype of only a single chemotaxis signaling mutant, e.g., cheA. Here, we addressed the role of chemotaxis in biofilm formation using a full set of chemotaxis signaling mutants in Helicobacter pylori, a class I carcinogen that infects more than half the worlds population and forms biofilms. Using mutants that lack each chemotaxis signaling protein, we found that chemotaxis signaling affected the biofilm initiation stage, but not mature biofilm formation. Surprisingly, some chemotaxis mutants elevated biofilm initiation, while others inhibited it in a manner that was not tied to chemotaxis ability or ligand input. Instead, the biofilm phenotype correlated with flagellar rotational bias. Specifically, mutants with a counterclockwise bias promoted biofilm initiation, e.g., ∆cheA, ∆cheW, or ∆cheV1; in contrast, those with a clockwise bias inhibited it, e.g., ∆cheZ, ∆chePep, or ∆cheV3. We tested this correlation using a counterclockwise bias-locked flagellum, which induced biofilm formation independent of the chemotaxis system. These CCW flagella, however, were not sufficient to induce biofilm formation, suggesting there are downstream players. Overall, our work highlights the new finding that flagellar rotational direction promotes biofilm initiation, with the chemotaxis signaling system operating as one mechanism to control flagellar rotation. IMPORTANCE: Chemotaxis signaling systems have been reported to contribute to biofilm formation in many bacteria; however, how they regulate biofilm formation remains largely unknown. Chemotaxis systems are composed of many distinct kinds of proteins, but most previous work analyzed the biofilm effect of loss of only a few. Here, we explored chemotaxis role during biofilm formation in the human-associated pathogenic bacterium Helicobacter pylori. We found that chemotaxis proteins are involved in biofilm initiation in a manner that correlated with how they affected flagellar rotation. Biofilm initiation was high in mutants with counterclockwise (CCW) flagellar bias and low in those with clockwise bias. We supported the idea that a major driver of biofilm formation is flagellar rotational direction using a CCW-locked flagellar mutant, which stays CCW independent of chemotaxis input and showed elevated biofilm initiation. Our data suggest that CCW-rotating flagella, independent of chemotaxis inputs, are a biofilm-promoting signal.

Microbial biofilms represent an important lifestyle for bacteria and are dynamic three-dimensional structures. Cyclic dimeric guanosine monophosphate (c-di-GMP) is a ubiquitous signaling molecule that is known to be tightly regulated with biofilm processes. While measurements of global levels of c-di-GMP have proven valuable toward understanding the genetic control of c-di-GMP production, there is a need for tools to observe the local changes of c-di-GMP production in biofilm processes. We have developed a label-free method for the direct detection of c-di-GMP in microbial colony biofilms using matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). We applied this method to the enteric pathogen Vibrio cholerae, the marine symbiont V. fischeri, and the opportunistic pathogen Pseudomonas aeruginosa PA14 and detected spatial and temporal changes in c-di-GMP signal that accompanied genetic alterations in factors that synthesize and degrade the compound. We further demonstrated how this method can be simultaneously applied to detect additional metabolites of interest from a single sample.

Impaired healing wounds do not proceed through the normal healing processes in a timely and orderly manner, and while they do eventually heal, their healing is not optimal. Chronic wounds, on the other hand, remain unhealed for weeks or months. In the US alone, chronic wounds impact ~8.5 million people and cost ~USD 28-90 billion per year, not accounting for the psychological and physical pain and emotional suffering that patients endure. These numbers are only expected to rise in the future as the elderly populations and the incidence of comorbidities such as diabetes, hypertension, and obesity increase. Over the last few decades, scientists have used a variety of approaches to treat chronic wounds, but unfortunately, to date, there is no effective treatment. Indeed, while there are thousands of drugs to combat cancer, there is only one single drug approved for the treatment of chronic wounds. This is in part because wound healing is a very complex process involving many phases that must occur sequentially and in a timely manner. Furthermore, models that fully mimic human chronic wounds have not been developed. In this review, we assess various models currently being used to study the biology of impaired healing and chronic non-healing wounds. Among them, this paper also highlights one model which shows significant promise; this model uses aged and obese db/db-/- mice and the chronic wounds that develop show characteristics of human chronic wounds that include increased oxidative stress, chronic inflammation, damaged microvasculature, abnormal collagen matrix deposition, a lack of re-epithelialization, and the spontaneous development of multi-bacterial biofilm. We also discuss how important it is that we continue to develop chronic wound models that more closely mimic those of humans and that can be used to test potential treatments to heal chronic wounds.

Biofilms are matrix-encased microbial communities that increase the environmental fitness and infectivity of many human pathogens including Vibrio cholerae. Biofilm matrix assembly is essential for biofilm formation and function. Known components of the V. cholerae biofilm matrix are the polysaccharide Vibrio polysaccharide (VPS), matrix proteins RbmA, RbmC, Bap1, and extracellular DNA, but the majority of the protein composition is uncharacterized. This study comprehensively analyzed the biofilm matrix proteome and revealed the presence of outer membrane proteins (OMPs). Outer membrane vesicles (OMVs) were also present in the V. cholerae biofilm matrix and were associated with OMPs and many biofilm matrix proteins suggesting that they participate in biofilm matrix assembly. Consistent with this, OMVs had the capability to alter biofilm structural properties depending on their composition. OmpU was the most prevalent OMP in the matrix, and its absence altered biofilm architecture by increasing VPS production. Single-cell force spectroscopy revealed that proteins critical for biofilm formation, OmpU, the matrix proteins RbmA, RbmC, Bap1, and VPS contribute to cell-surface adhesion forces at differing efficiency, with VPS showing the highest efficiency whereas Bap1 showing the lowest efficiency. Our findings provide new insights into the molecular mechanisms underlying biofilm matrix assembly in V. cholerae, which may provide new opportunities to develop inhibitors that specifically alter biofilm matrix properties and, thus, affect either the environmental survival or pathogenesis of V. cholerae.IMPORTANCECholera remains a major public health concern. Vibrio cholerae, the causative agent of cholera, forms biofilms, which are critical for its transmission, infectivity, and environmental persistence. While we know that the V. cholerae biofilm matrix contains exopolysaccharide, matrix proteins, and extracellular DNA, we do not have a comprehensive understanding of the majority of biofilm matrix components. Here, we discover outer membrane vesicles (OMVs) within the biofilm matrix of V. cholerae. Proteomic analysis of the matrix and matrix-associated OMVs showed that OMVs carry key matrix proteins and Vibrio polysaccharide (VPS) to help build biofilms. We also characterize the role of the highly abundant outer membrane protein OmpU in biofilm formation and show that it impacts biofilm architecture in a VPS-dependent manner. Understanding V. cholerae biofilm formation is important for developing a better prevention and treatment strategy framework.

Pustular mats from Shark Bay, Western Australia, host complex microbial communities bound within an organic matrix. These mats harbour many poorly characterized organisms with low relative abundances (

Reductions in nonresidential water demand during the COVID-19 pandemic highlighted the importance of understanding how water age impacts drinking water quality and microbiota in piped distribution systems. Using benchtop model distribution systems, we aimed to characterize the impacts of elevated water age on microbiota in bulk water and pipe wall biofilms. Five replicate constant-flow reactors were fed with municipal chloraminated tap water for 6 months prior to building closures and 7 months after. After building closures, chloramine levels entering the reactors dropped; in the reactor bulk water and biofilms the mean cell counts and ATP concentrations increased over an order of magnitude while the detection of opportunistic pathogens remained low. Water age, and the corresponding physicochemical changes, strongly influenced microbial abundance and community composition. Differential initial microbial colonization also had a lasting influence on microbial communities in each reactor (i.e., historical contingency).

Methicillin-resistant Staphylococcus aureus (MRSA) is an important zoonotic pathogen associated with a wide range of infections in humans and animals. Thus, the emergence of MRSA clones poses an important threat to human and animal health. This study is aimed at elucidating the genomics insights of a strong biofilm-producing and multidrug-resistant (MDR) S. aureus MTR_BAU_H1 strain through whole-genome sequencing (WGS). The S. aureus MTR_BAU_H1 strain was isolated from food handlers hand swabs in Bangladesh and phenotypically assessed for antimicrobial susceptibility and biofilm production assays. The isolate was further undergone to high throughput WGS and analysed using different bioinformatics tools to elucidate the genetic diversity, molecular epidemiology, sequence type (ST), antimicrobial resistance, and virulence gene distribution. Phenotypic analyses revealed that the S. aureus MTR_BAU_H1 strain is a strong biofilm-former and carries both antimicrobial resistance (e.g., methicillin resistance; mecA, beta-lactam resistance; blaZ and tetracycline resistance; tetC) and virulence (e.g., sea, tsst, and PVL) genes. The genome of the S. aureus MTR_BAU_H1 belonged to ST1930 that possessed three plasmid replicons (e.g., rep16, rep7c, and rep19), seven prophages, and two clustered regularly interspaced short palindromic repeat (CRISPR) arrays of varying sizes. Phylogenetic analysis showed a close evolutionary relationship between the MTR_BAU_H1 genome and other MRSA clones of diverse hosts and demographics. The MTR_BAU_H1 genome harbours 42 antimicrobial resistance genes (ARGs), 128 virulence genes, and 273 SEED subsystems coding for the metabolism of amino acids, carbohydrates, proteins, cofactors, vitamins, minerals, and lipids. This is the first-ever WGS-based study of a strong biofilm-producing and MDR S. aureus strain isolated from human hand swabs in Bangladesh that unveils new information on the resistomes (ARGs and correlated mechanisms) and virulence potentials that might be linked to staphylococcal pathogenesis in both humans and animals.

BackgroundBiofilms in sulfide-rich springs present intricate microbial communities that play pivotal roles in biogeochemical cycling. We studied chemoautotrophically based biofilms that host diverse CPR bacteria and grow in sulfide-rich springs to investigate microbial controls on biogeochemical cycling.ResultsSulfide springs biofilms were investigated using bulk geochemical analysis, genome-resolved metagenomics, and scanning transmission X-ray microscopy (STXM) at room temperature and 87 K. Chemolithotrophic sulfur-oxidizing bacteria, including Thiothrix and Beggiatoa, dominate the biofilms, which also contain CPR Gracilibacteria, Absconditabacteria, Saccharibacteria, Peregrinibacteria, Berkelbacteria, Microgenomates, and Parcubacteria. STXM imaging revealed ultra-small cells near the surfaces of filamentous bacteria that may be CPR bacterial episymbionts. STXM and NEXAFS spectroscopy at carbon K and sulfur L2,3 edges show that filamentous bacteria contain protein-encapsulated spherical elemental sulfur granules, indicating that they are sulfur oxidizers, likely Thiothrix. Berkelbacteria and Moranbacteria in the same biofilm sample are predicted to have a novel electron bifurcating group 3b [NiFe]-hydrogenase, putatively a sulfhydrogenase, potentially linked to sulfur metabolism via redox cofactors. This complex could potentially contribute to symbioses, for example, with sulfur-oxidizing bacteria such as Thiothrix that is based on cryptic sulfur cycling. One Doudnabacteria genome encodes adjacent sulfur dioxygenase and rhodanese genes that may convert thiosulfate to sulfite. We find similar conserved genomic architecture associated with CPR bacteria from other sulfur-rich subsurface ecosystems.ConclusionsOur combined metagenomic, geochemical, spectromicroscopic, and structural bioinformatics analyses of biofilms growing in sulfide-rich springs revealed consortia that contain CPR bacteria and sulfur-oxidizing Proteobacteria, including Thiothrix, and bacteria from a new family within Beggiatoales. We infer roles for CPR bacteria in sulfur and hydrogen cycling. Video Abstract.

Purpose: To evaluate the performance of fully crystallized zirconia-reinforced lithium silicate (Celtra Duo, ZLS-CD), partially crystallized zirconia-reinforced lithium silicate (Vita Suprinity, ZLS-VS), and partially sintered lithium disilicate-based (IPS e.max CAD, LD) glass-ceramics submitted to polishing, glazing, or no surface treatment after aging. Material and Methods: Samples of each glass-ceramic material were subjected to polishing with rubber cups (POL), glazing (GL), or no treatment (control: unpolished) and afterward aged with 18,000 thermal cycles (5°C to 55°C). The average roughness, 2D and 3D morphology, contact angle, multispecies biofilm formation (Streptococcus mutans and Candida albicans), and mechanical strength were evaluated with atomic force microscopy (AFM, n = 5), sessile-drop goniometry (n = 5), spectrophotometry (n = 5), and the flexural strength test (n = 10), respectively. Data were analyzed using two-way ANOVA and Tukey test (a = 5%). Results: POL produced lower surface roughness than GL, and ZLS-CD presented higher roughness than LD (P < .05). Surfaces without polishing displayed higher roughness than the POL group (P < .001), greater contact angle (P < .001), and significant morphologic changes, regardless of the glassceramic material. Irrespective of the treatment, the contact angle was higher in the ZLS-CD group, and regardless of the material, there was higher biofilm formation and lower flexural strength of the unpolished compared to the POL or GL ceramics. Conclusions: POL promoted lower roughness and minor morphologic surface alterations, but biofilm formation and flexural strength were similar to the GL group. In general, ZLSCD and ZLS-VS showed more similar behavior than LD, which makes ZLS glass-ceramic a good option for indirect restorations. [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]

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: 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]

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]

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]

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]

Summary: From recent literature and research studies, it has been found that some bacterial strains have abilities with probiotic activities to produce B vitamins, which play essential roles in maintaining human health. Oligosaccharides can promote the beneficial microbes, however, the specific effects of oligosaccharides on B vitamins‐producing ability of probiotic strains have not been clarified. This study evaluated the effect of different oligosaccharides on the probiotic properties and B vitamin‐producing ability of 21 selected probiotic strains. The obtained results suggested that the strains could utilise oligosaccharides as the sole carbon source, and the hydrophobicity, auto‐aggregation, and biofilm formation of probiotic strains were specific regulated after fermentation with different oligosaccharides. In particular, the oligosaccharides had different influences on the levels of extracellular B vitamins produced by probiotic strains. These findings provide the foundation for studies on the B vitamins‐producing probiotic strains and their application in functional foods to prevent B vitamins deficiency. [ABSTRACT FROM AUTHOR]

Introduction: Fragile X syndrome (FXS) is the most common cause of hereditary genetic disorder in a single gene characterised by intellectual disability. Behavioural features such as autism, hyperactivity and anxiety disorder may be present. Biofilm development and pathogenicity of Streptococcus mutans may be altered because FXS renders the dental approach and oral hygiene more complex. Objectives: The purpose of this study was to compare the levels of transcripts for VicRK and CovR of S. mutans isolated from FXS patients with the levels of transcripts for VicRK and CovR of standard strain ATCC, using a quantitative polymerase chain reaction (qPCR). Methods: The caries experience index was assessed by the International Caries Detection and Assessment System (ICDAS), Periodontal Condition Index (PCI) and Invasive Dental Treatment Need Index (INI). Results: The clinical index findings revealed a high rate of caries cavities and bleeding on probing of FXS patients. When VicRK and CovR transcript levels were compared with the reference strain, Fragile X patients were found to have significantly higher values. Conclusion: The present study demonstrated that FXS patients have more adverse clinical conditions, with increased biofilm accumulation and virulence. When combined with behavioural abnormalities, these patients become even more vulnerable to dental caries. [ABSTRACT FROM AUTHOR]

The rampant use of antibiotics has led to the emergence of multidrug resistance and is often coupled with gut dysbiosis. To circumvent the harmful impact of antibiotics, probiotics have emerged as an effective intervention. However, while the new probiotics are being added to the list, more recently, the nature and role of their counterparts, viz. prebiotics, postbiotics and parabiotics have also drawn considerable attention. As such, intricate relationships among these gut-biotics vis-à-vis their role in imparting health benefits is to be delineated in a holistic manner. Prebiotic dietary fibers are selectively fermented by probiotics and promote their colonization in the gut. The proliferation of probiotics leads to production of fermentation by-products (postbiotics) which affect the growth of enteropathogens by lowering the pH and producing inhibitory bacteriocins. After completing life-cycle, their dead remnants (parabiotics e.g. exopolysaccharides and cell wall glycoproteins) also inhibit adhesion and biofilm formation of pathogens on the gut epithelium. These beneficial effects are not just endemic to gut but a systemic response is witnessed at different gut-organ axes. Thus, to decipher the role of probiotics, it is imperative to unravel the interdependence between these components. This review elaborates on the recent advancements on various aspects of these gut-biotics and the mechanism of potential attributes like anti-oxidant, anti-inflammatory, anti-neoplastic, anti-lipidemic and anti-hyperglycemic benefits. [ABSTRACT FROM AUTHOR]

During 2018–2021, eight septic transfusion reactions occurred from transfusion of platelet units contaminated with Acinetobacter spp., Staphylococcus saprophyticus, Leclercia adecarboxylata, or a combination of those environmental organisms. Whether biofilm formation contributed to evasion of bacterial risk mitigations, including bacterial culture, point-of-care testing, or pathogen-reduction technology, is unclear. We designed a 12-well plate-based method to evaluate environmental determinants of single-species and multispecies biofilm formation in platelets. We evaluated bacteria isolated from septic transfusion reactions for biofilm formation by using crystal violet staining and enumeration of adherent bacteria. Most combinations of bacteria had enhanced biofilm production compared with single bacteria. Combinations involving L. adecarboxylata had increased crystal violet biofilm production and adherent bacteria. This study demonstrates that transfusion-relevant bacteria can produce biofilms well together. More work is needed to clarify the effect of biofilms on platelet bacterial risk control strategies, but US Food and Drug Administration– recommended strategies remain acceptable. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa (P. aeruginosa) is a major pathogen that causes infectious diseases. It has high tendency to form biofilms, resulting in the failure of traditional antibiotic therapies. Inspired by the phenomenon that co-culture of Escherichia coli (E. coli) and P. aeruginosa leads to a biofilm reduction, we reveal that E. coli exopolysaccharides (EPS) can disrupt P. aeruginosa biofilm and increase its antibiotic susceptibility. The results show that E. coli EPS effectively inhibit biofilm formation and disrupt mature biofilms in P. aeruginosa, Staphylococcus aureus , and E. coli itself. The maximal inhibition and disruption rates against P. aeruginosa biofilm are 40 % and 47 %, respectively. Based on the biofilm-disrupting ability of E. coli EPS, we develop an E. coli EPS/antibiotic combining strategy for the treatment of P. aeruginosa biofilms. The combination with E. coli EPS increases the antibacterial efficiency of tobramycin against P. aeruginosa biofilms in vitro and in vivo. This study provides a promising strategy for treating biofilm infections. Biofilm formation is a leading cause of chronic infections. It blocks antibiotics, increases antibiotic-tolerance, and aids in immune evasion, thus representing a great challenge in clinic. This study proposes a promising approach to combat pathogenic Pseudomonas aeruginosa (P. aeruginosa) biofilms by combining Escherichia coli exopolysaccharides with antibiotics. This strategy shows high efficiency in different P. aeruginosa stains, including two laboratory strains, PAO1 and ATCC 10145, as well as a clinically acquired carbapenem-resistant strain. In addition, in vivo experiments have shown that this approach is effective against implanted P. aeruginosa biofilms and can prevent systemic inflammation in mice. This strategy offers new possibilities to address the clinical failure of conventional antibiotic therapies for microbial biofilms. [Display omitted] [ABSTRACT FROM AUTHOR]

Introduction: Enteral feeding tubes are commonly utilized in the neonatal intensive care unit (NICU) due to the underdevelopment of coordination between sucking, swallowing, and breathing, or due to various diseases affecting the respiratory, cardiovascular, gastrointestinal, or neurological systems. The aim of the study was to investigate the differences in bacterial colonization patterns in hospitalized infants who received enteral feeding through either nasogastric (NG) or orogastric (OG) feeding tubes. Materials and Methods: This study was a hospital-based cross-sectional investigation that was carried out on infants who were admitted to the NICU. The NICU gathered feeding tubes throughout 4 months, beginning in August 2022 and continuing through December 2022. In addition, informed consent was collected from the participant's parents or legal guardians for the entire group of people who took part in the research. The fact that the patient participated in this study had no bearing on the level of care that they were given. The research team gave serious consideration to recruiting any of the newborns who were receiving medical attention in the NICU and who had a feeding tube inserted during the time that sample collection was taking place. The infants did not receive any probiotics as a form of treatment in any of the cases. Results: Infants with NG tubes had a significantly higher number of C-sections (P = 0.04), infants with NG tube were exclusively breastfed (P = 0.02), and one or more dose of antenatal steroids was administered more in infants with OG tube (P = 0.04). The most common types of bacteria found in NG and OG tubes were Proteobacteria (with a mean relative abundance of 50% and 60%, respectively), Firmicutes (with a mean relative abundance of 33% and 23%, respectively), and Actinobacteria (9% and 7%, respectively). Conclusion: Oral versus nasal feeding tube insertion was found to have a greater influence on bacterial colonization than any of the other clinical factors that were evaluated. [ABSTRACT FROM AUTHOR]

Efflux pump inhibitors are a potential therapeutic strategy for managing antimicrobial resistance and biofilm formation. This article evaluated the effect of carbonyl cyanide m-chlorophenyl hydrazone (CCCP) on the biofilm growth dynamics and the production of virulence factors by Burkholderia pseudomallei. The effects of CCCP on planktonic, growing, and mature biofilm, interaction with antibacterial drugs, and protease and siderophore production were assessed. CCCP MICs ranged between 128 and 256 µM. The CCCP (128 µM) had a synergic effect with all the antibiotics tested against biofilms. Additionally, CCCP reduced (p <.05) the biomass of biofilm growth and mature biofilms at 128 and 512 µM, respectively. CCCP also decreased (p <.05) protease production by growing (128 µM) and induced (p <.05) siderophore release by planktonic cells (128 µM) growing biofilms (12.8 and 128 µM) and mature biofilms (512 µM). CCCP demonstrates potential as a therapeutic adjuvant for disassembling B. pseudomallei biofilms and enhancing drug penetration. [ABSTRACT FROM AUTHOR]

The bacterial community from a cooling water system was investigated through culture-dependent and independent strategies, and the responses of planktonic and sessile bacteria (grown in glass slides and stainless-steel coupons) to antimicrobials of industrial and clinical use were assessed. The morphotypes with higher biofilm-forming potential were Pseudoxanthomonas sp., Rheinheimera sp., Aeromonas sp. and Staphylococcus sp., and the first also exhibited lower susceptibility to all antibiotics and biocides tested. 16S rRNA high throughput sequencing indicated that Pseudomonadota (77.1% on average, sd 11.1%), Bacteroidota (8.4, sd 5.7%), and Planctomycetota (3.0, sd 1.3%) were the most abundant phyla. KEGG orthologs associated with antibiotics and biocide resistance were abundant in all samples. Although the minimum inhibitory and bactericidal concentrations were generally higher for biofilms, morphotypes in planktonic form also showed high levels of resistance, which could be associated with biofilm cells passing into the planktonic phase. Overall, monochloramine was the most effective biocide. [ABSTRACT FROM AUTHOR]

Understanding factors influencing Listeria monocytogenes biofilms aid in developing more effective elimination/prevention strategies. This study examined the effect of temperature (4 °C, 21 °C, 30 °C), materials (stainless steel 316 L with 2B and 2 R finishes, glass, and polypropylene), and slope (0°/horizontal or 90°/vertical) on mono- and dual-species biofilms using two L. monocytogenes strains and one Pseudomonas aeruginosa strain. All biofilms were grown in 10% TSB for 24 h and analyzed using culture-based methods. Additionally, the architecture of monospecies biofilms was studied using fluorescence microscopy. Overall, P. aeruginosa showed higher biofilm formation potential (6.2 log CFU/cm2) than L. monocytogenes (4.0 log CFU/cm2). Temperature greatly influenced P. aeruginosa and varied for L. monocytogenes. The slope predominantly influenced L. monocytogenes monospecies biofilms, with cell counts increasing by up to 2 log CFU/cm2. Surface material had little impact on biofilm formation. The study highlights the varying effects of different parameters on multispecies biofilms and the importance of surface geometry. HIGHLIGHTS: Surface material does not affect L. monocytogenes or P. aeruginosa biofilms L. monocytogenes produces more biofilm on horizontal surfaces than on vertical surfaces In dual-species biofilm, L. monocytogenes shows enhanced biofilm production Increased temperature often results in enhanced biofilm formation [ABSTRACT FROM AUTHOR]

Key points Treatment of cystic fibrosis‐related chronic rhinosinusitis should target sinonasal biofilms. NaHCO3 salts with/without xylitol have limited antibiofilm properties, whereas rhDNAse has not. Phage effectivity varies and depends on the phage and the combination with antibiotics. [ABSTRACT FROM AUTHOR]

The dissemination of antibiotic resistance (AR) through various environments and the role of AR hotspots in public health crises are gaining increasing attention. Aquatic biofilms are speculated to play a significant role in AR spread due to their collection of diverse microorganisms and facilitation of horizontal gene transfer (HGT). However, few studies have characterized the AR genes (resistome) present in natural river biofilms. The goal of this study was to use MinION long-read sequencing to analyze the microbiome, resistome, and mobile genetic elements (MGEs) in periphyton (epilithic biofilms) (n = 56) from a multiuse watershed in Ohio, to elucidate the role of periphyton in clinically relevant AR. Key members of the periphyton microbiome included Flavobacterium and Aeromonas. Overall, periphyton microbial communities shifted with season and location. Specifically, species of Porphyrobacter and Cyanobacteria were more abundant in biofilms during the summer season. Potentially pathogenic bacteria, including the family Enterobacteriaceae, the fish pathogen Pseudomonas koreensis, and the human pathogen Shigella flexneri,weremore abundant in sites downstream of the large city, Columbus, OH, than upstream. The periphyton resistome carried diverse AR genes for a variety of classes, but had minimal clinical relevance. Escherichia, Escherichia coli, and Muvirus were common hosts of AR genes (ARGs) and MGEs. Pseudomonas and Cyanobacteria were frequently MGE hosts, but not AR genes, indicating the potentially important role of these taxa in HGT within and around biofilms. While the sequencing depth in this study was relatively shallow, these findings highlight the mobility potential for the transmission of ARGs in river biofilms. [ABSTRACT FROM AUTHOR]

Dairy mastitis is one of the most common diseases in dairy farming, and the formation of pathogenic bacteria biofilms may be an important reason why traditional antibiotic therapy fails to resolve some cases of dairy mastitis. We isolated and identified three strains of A. lwoffii were with strong biofilm forming ability from dairy cow mastitis samples from Chongqing dairy farms in China. In order to investigate the effect of novel anti-biofilm peptide CRAMP-34 on A.lwoffii biofilms, the anti-biofilm effect was evaluated by crystal violet staining, biofilms viable bacteria counting and confocal laser scanning microscopy (CLSM). In addition, transcriptome sequencing analysis, qRT-PCR and phenotypic verification were used to explore the mechanism of its action. The results showed that CRAMP-34 had a dose-dependent eradicating effect on A. lwoffii biofilms. Transcriptome sequencing analysis showed that 36 differentially expressed genes (11 up-regulated and 25 down-regulated) were detected after the intervention with the sub-inhibitory concentration of CRAMP-34. These differentially expressed genes may be related to enzyme synthesis, fimbriae, iron uptake system, capsular polysaccharide and other virulence factors through the functional analysis of differential genes. The results of subsequent bacterial motility and adhesion tests showed that the motility of A.lwoffii were enhanced after the intervention of CRAMP-34, but there was no significant change in adhesion. It was speculated that CRAMP-34 may promote the dispersion of biofilm bacteria by enhancing the motility of biofilm bacteria, thereby achieving the effect of eradicating biofilms. Therefore, these results, along with our other previous findings, suggest that CRAMP-34 holds promise as a new biofilm eradicator and deserves further research and development. [ABSTRACT FROM AUTHOR]

In this study, thermoplastic starch (TPS) biofilms were developed using starch isolated from the seeds of Melicoccus bijugatus (huaya) and reinforced with bentonite clays at concentrations of 1%, 3%, and 5% by weight. Novelty of this research lies in utilizing a non-conventional starch source and enhancing properties of TPS through clay reinforcement. FTIR analysis verified bentonite's nature of clays, while SEM analysis provided insights into morphology and agglomeration behavior. Key findings include a notable increase in biofilm thickness and elastic modulus with higher clay content. Specifically, tensile strength of biofilms improved from 2.5 MPa for pure TPS to 5.0 MPa with 5% clay reinforcement. The elastic modulus increased from 25 MPa (TPS) to 60 MPa (5% clay). Thermal stability also showed enhancement, with initial degradation temperature increasing from 110 °C for pure TPS to 130 °C for TPS with 5% clay. Water vapor permeability (WVP) tests demonstrated a decrease in WVP values from 4.11 × 10−10 g m−1 s−1 Pa−1 for pure TPS to 2.09 × 10−10 g m−1 s−1·Pa−1 for TPS with 5% clay, indicating a significant barrier effect due to clay dispersion. These results suggest that biofilms based on huaya starch and reinforced with bentonite clay have considerable potential for sustainable food packaging applications, offering enhanced mechanical and barrier properties. [ABSTRACT FROM AUTHOR]

Background: Oral microbiota comprises polymicrobial communities shaped by mutualistic coevolution with the host, contributing to homeostasis and regulating immune function. Nevertheless, dysbiosis of oral bacterial communities is associated with a number of clinical symptoms that ranges from infections to oral cancer. Peri-implant diseases are biofilm-associated inflammatory conditions affecting the soft and hard tissues around dental implants. Characterization and identification of the biofilm community are essential for the understanding of the pathophysiology of such diseases. For that sampling methods should be representative of the biofilm communities Therefore, there is a need to know the effect of different sampling strategies on the biofilm characterization by next generation sequencing. Methods: With the aim of selecting an appropriate microbiome sampling procedure for periimplant biofilms, next generation sequencing was used for characterizing the bacterial communities obtained by three different sampling strategies two months after transepithelial abutment placement: adjacent periodontal crevicular fluid (ToCF), crevicular fluid from transepithelial abutment (TACF) and transepithelial abutment (TA). Results: Significant differences in multiple alpha diversity indices were detected at both the OTU and the genus level between different sampling procedures. Differentially abundant taxa were detected between sample collection strategies, including peri-implant health and disease related taxa. At the community level significant differences were also detected between TACF and TA and also between TA and ToCF. Moreover, differential network properties and association patterns were identified. Conclusions: The selection of sample collection strategy can significantly affect the community composition and structure. Trial registration: This research is part of a randomized clinical trial that was designed to assess the effect of transepithelial abutment surface on the biofilm formation. The trial was registered at Trial Registration ClinicalTrials.gov under the number NCT03554876. [ABSTRACT FROM AUTHOR]

The significance of this study lies in its exploration of bioactive plant extracts as a promising avenue for combating oral bacterial pathogens, offering a novel strategy for biofilm eradication that could potentially revolutionize oral health treatments. Oral bacterial infections are common in diabetic patients; however, due to the development of resistance, treatment options are limited. Considering the excellent antimicrobial properties of phenolic compounds, we investigated them against isolated oral pathogens using in silico and in vitro models. We performed antibiogram studies and minimum inhibitory concentration (MIC), antibiofilm, and antiquorum sensing activities covering phenolic compounds. Bacterial strains were isolated from female diabetic patients and identified by using 16S rRNA sequencing as Pseudomonas aeruginosa, Bacillus chungangensis, Bacillus paramycoides, and Paenibacillus dendritiformis. Antibiogram studies confirmed that all strains were resistant to most tested antibiotics except imipenem and ciprofloxacin. Molecular docking analysis revealed the significant interaction of rutin, quercetin, gallic acid, and catechin with transcription regulator genes 1RO5, 4B2O, and 5OE3. All tested molecules followed drug-likeness rules except rutin. The MIC values of the tested compounds varied from 0.0625 to 0.5 mg/mL against clinical isolates. Significant antibiofilm activity was recorded in the case of catechin (73.5% ± 1.6% inhibition against B. paramycoides), cinnamic acid (80.9% ± 1.1% inhibition against P. aeruginosa), and vanillic acid and quercetin (65.5% ± 1.7% and 87.4% ± 1.4% inhibition, respectively, against B. chungangensis) at 0.25-0.125 mg/mL. None of the phenolic compounds presented antiquorum sensing activity. It was, therefore, concluded that polyphenolic compounds may have the potential to be used against oral bacterial biofilms, and further detailed mechanistic investigations should be performed. [ABSTRACT FROM AUTHOR]

Biofilms are subjected to many environmental pressures that can influence community structure and physiology. In the oral cavity, and many other environments, biofilms are exposed to forces generated by fluid flow; however, our understanding of how oral biofilms respond to these forces remains limited. In this study, we developed a linear rocker model of fluid flow to study the impact of shear forces on Streptococcus gordonii and dental plaque‐derived multispecies biofilms. We observed that as shear forces increased, S. gordonii biofilm biomass decreased. Reduced biomass was largely independent of overall bacterial growth. Transcriptome analysis of S. gordonii biofilms exposed to moderate levels of shear stress uncovered numerous genes with differential expression under shear. We also evaluated an ex vivo plaque biofilm exposed to fluid shear forces. Like S. gordonii, the plaque biofilm displayed decreased biomass as shear forces increased. Examination of plaque community composition revealed decreased diversity and compositional changes in the plaque biofilm exposed to shear. These studies help to elucidate the impact of fluid shear on oral bacteria and may be extended to other bacterial biofilm systems. [ABSTRACT FROM AUTHOR]

Chemotaxis–the movement of cells along chemical gradients—leads to collective behaviors when cells coordinate their movements. Here, using Escherichia coli as a model, we demonstrate a distinct type of bacterial collective response in acidic environments containing organic acids. Bacterial populations immersed in such environments collectively condensed into millimeter-sized focal points. Furthermore, this bacterial condensation fostered the formation of small, tightly packed cell aggregates, resembling non-surface-attached biofilms. These cell aggregates were physically displaced by the free-swimming condensing cells, leading to the segregation of the two cell populations. Bacterial condensation relied on feedback between the tendency of these bacteria to neutralize the pH and their chemotactic repulsion from low pH. Sustained cell condensation occurred when the bacteria occupied only part of the acidic environment, either dynamically or due to physical constraints. Such condensed bacterial populations can mitigate acid stress more efficiently, a principle that may be applicable to other stress conditions. Under uniform pH stress, bacteria spontaneously condense into millimeter-sized focal points. This chemotaxis-driven collective response fosters the formation of tightly packed cell communities and allows cells to mitigate the stress more efficiently. [ABSTRACT FROM AUTHOR]

Introduction: Bacteriophages have been shown to penetrate biofilms and replicate if they find suitable host cells. Therefore, these viruses appear to be a good option to tackle the biofilm problem and complement or even substitute more conventional antimicrobials. However, in order to successfully remove biofilms, in particular mature biofilms, phages may need to be administered along with other compounds. Phage-derived proteins, such as endolysins or depolymerases, offer a safer alternative to other compounds in the era of antibiotic resistance. Methods: This study examined the interactions between phage Kayvirus rodi with a polysaccharide depolymerase (Dpo7) from another phage (Rockefellervirus IPLA7) against biofilms formed by different Staphylococcus aureus strains, as determined by crystal violet staining, viable cell counts and microscopy analysis. Results and discussion: Our results demonstrated that there was synergy between the two antimicrobials, with a more significant decreased in biomass and viable cell number with the combination treatment compared to the phage and enzyme alone. This observation was confirmed by microscopy analysis, which also showed that polysaccharide depolymerase treatment reduced, but did not eliminate extracellular matrix polysaccharides. Activity assays on mutant strains did not identify teichoic acids or PNAG/PIA as the exclusive target of Dpo7, suggesting that may be both are degraded by this enzyme. Phage adsorption to S. aureus cells was not significantly altered by incubation with Dpo7, indicating that the mechanism of the observed synergistic interaction is likely through loosening of the biofilm structure. This would allow easier access of the phage particles to their host cells and facilitate infection progression within the bacterial population. [ABSTRACT FROM AUTHOR]

Introduction: Pseudomonas aeruginosa is a ubiquitous pathogen that causes various infectious diseases through the regulation of quorum sensing (QS). The strategy of interfering with the QS systems of P. aeruginosa, coupled with a reduction in the dosage of conventional antibiotics, presents a potential solution to treating infection and mitigating antibiotic resistance. In this study, seven cinnamoyl hydroxamates were synthesized to evaluate their inhibitory effects on QS of P. aeruginosa. Among these cinnamic acid derivatives, we found cinnamoyl hydroxamic acid (CHA) and 3-methoxy-cinnamoyl hydroxamic acid (MCHA) were the two most effective candidates. Furtherly, the effect of CHA and MCHA on the production of virulence factors and biofilm of P. aeruginosa were evaluated. Ultimately, our study may offer promising potential for treating P. aeruginosa infections and reducing its virulence. Methods: The disc diffusion test were conducted to evaluate inhibitory effects on QS of seven cinnamoyl hydroxamates. The influence of CHA and MCHA on the production of virulence and flagellar motility of P. aeruginosa was furtherly explored. Scanning electron microscopy (SEM) experiment were conducted to evaluate the suppression of CHA and MCHA on the formed biofilm of P. aeruginosa. RT-qPCR was used to detect rhlI, lasA, lasB, rhlA, rhlB, and oprL genes in P. aeruginosa. In silico docking study was performed to explore the molecular mechanism of CHA and MCHA. The synergistic effects of CHA with gentamicin were detected on biofilm cell dispersal. Result: After treatment of CHA or MCHA, the production of multiple virulence factors, including pyocyanin, proteases, rhamnolipid, and siderophore, and swimming and swarming motilities in P. aeruginosa were inhibited significantly. And our results showed CHA and MCHA could eliminate the formed biofilm of P. aeruginosa. RT-qPCR revealed that CHA and MCHA inhibited the expression of QS related genes in P. aeruginosa. Molecular docking indicated that CHA and MCHA primarily inhibited the RhlI/R system in P. aeruginosa by competing with the cognate signaling molecule C4-HSL.Additionally, CHA exhibited potent synergistic effects with gentamicin on biofilm cell dispersal. Discussion: P. aeruginosa is one of the most clinically and epidemiologically important bacteria and a primary cause of catheter-related urinary tract infections and ventilator-associated pneumonia. This study aims to explore whether cinnamoyl hydroxamates have inhibitory effects on QS. And our results indicate that CHA and MCHA, as two novel QSIs, offer promising potential for treating P. aeruginosa infections and reducing its virulence. [ABSTRACT FROM AUTHOR]

Given the increasing occurrence of invasive fungal infections and the limited efficacy of modern antifungal medications, it is crucial to disseminate information regarding the potential sources of nosocomial mycoses through the One Health approach. This study investigated the presence and antifungal susceptibility of fungi in biofilm and water samples obtained from the drinking water distribution system (DWDS) of hospitals. The positivity rate for fungi in biofilm and water samples was 41% and 9%, respectively, with Aspergillus species, a significant causative agent of nosocomial mycoses, being the predominant fungi identified. Analysis of antifungal susceptibility test revelead a comparable resistance profile between some isolated species from the DWDS and those reported for certain clinical samples. While further research is required to determine the specific contribution of waterborne fungi to nosocomial fungal infections, our results emphasize the importance of controlling biofilm formation within DWDSs, particularly in high-risk hospital wards. [ABSTRACT FROM AUTHOR]

Background: Using endodontic sealers with long-term antimicrobial properties can increase the success of endodontic treatment. This study aimed to assess the antimicrobial activity over time of two calcium silicate (CS)-based sealers, AH Plus Bioceramic and BioRoot RCS, and to compare them with an epoxy resin-based sealer, AH Plus Jet, against mature polymicrobial biofilms grown on human radicular dentin. Methods: The antimicrobial activity of the sealers was tested using a direct contact test after 1 and 6 weeks of contact with the biofilms. Cell viability was determined by the adenosine triphosphate (ATP) method and flow cytometry (FC). The results of the ATP test were analyzed using an ANOVA with Welch's correction, followed by the Games–Howell test. The number of cells with damaged membranes obtained by FC in each period was compared by means of an ANOVA and Duncan's test. For the comparison between times, a Student's t-test was used. Results: Globally, after a week of contact, the epoxy resin-based sealer obtained the best results. However, at 6 weeks, the two CSs showed the highest antimicrobial efficacy, with a significant increase in this activity over time. Conclusions: Calcium silicate-based sealers exert long-term antimicrobial activity against endodontic biofilms. [ABSTRACT FROM AUTHOR]

The newly synthesized 1,2,3-triazole-thiazole hybrids were first evaluated for their antimicrobial activity against different microbial strains. Most of it showed a marked selectivity against Gram-positive and Gram-negative bacterial strains. The MIC assay was then assessed; for S. aureus, 4a was equipotent to the reference neomycin, while 3a, 3b, and 8b were 2-fold lower. For E. coli, compounds 3a, 4a, and 8c were equipotent to neomycin, while 5a was 8-fold higher, and 8d was 2-fold higher. Most of tested compounds showed superiority to the reference drug against C. albicans; 8a and 8e showed MIC value of 16-fold higher than neomycin, while 3a was 8-fold higher. Also, 3b and 8f were 4-fold higher; 8d was 2-fold higher, while 5a was equipotent to neomycin against the same microbe. Further biofilm formation inhibition assay was conducted to the most active compounds, 5a was the most active against the three types of bacterial strains. [ABSTRACT FROM AUTHOR]