Search Results (2,243)

The human gastrointestinal tract hosts a complex ecosystem known as the gut microbiota, which plays a crucial part in digestion and immune system function. Among the clinically recognized manifestations of dysbiosis in this system are Small Intestinal Bacterial Overgrowth (SIBO), Intestinal Methanogen Overgrowth (IMO), Small Intestinal Fungal Overgrowth (SIFO), and Large Intestinal Bacterial Overgrowth (LIBO). This study aims to investigate the complex pathophysiological mechanisms underlying these syndromes and their diagnostics and therapeutic options, focusing primarily on the roles of methane-producing archaea and fungal overgrowth. The methods employed in this study involve a comprehensive analysis and synthesis of peer-reviewed articles, systematic reviews, clinical trials, and meta-analyses. This review summarizes that methane production by Methanobrevibacter smithii was linked to altered fermentation, reduced microbial diversity, and slowed intestinal transit. Fungal species were associated with increased intestinal permeability, inflammation, and biofilm formation. Targeted interventions addressing microbial imbalances demonstrated potential therapeutic value. This review highlights the complex and multifactorial nature of gut dysbiosis, revealing its impact beyond the gastrointestinal tract. While emerging therapies targeting methanogens, fungi, and biofilms show promise, further research is essential to optimize their clinical application. The findings emphasize the need for interdisciplinary collaboration to refine diagnostic and therapeutic strategies. Full article

Escherichia coli (E. coli) is a severe foodborne pathogen, and the formation of its biofilm can enhance bacterial virulence and reduce antibiotic sensitivity, posing a significant threat to human and animal health. Ferulic Acid (FA) is a natural active product that has been proven to possess various biological activities, including anti-inflammatory, antioxidant, and antitumor properties. This study evaluated the inhibitory effect of FA on the biofilm formation of E. coli through crystal violet (CV) staining and scanning electron microscopy (SEM) and investigated the synergistic effect of FA with antibiotics, using the alamar blue (AB) assay. In addition, the regulatory effect of FA on the transcription of biofilm-related genes was analyzed using qRT-PCR technology. The results showed that FA could significantly inhibit biofilm formation, reduce the production of extracellular polymeric substances (EPS), and weaken bacterial motility, without affecting bacterial growth and metabolic activity. qRT-PCR analysis revealed that FA significantly downregulated the expression of curli-related gene csgD, flagella-related genes (flhC, flhD, and motA), and type I fimbriae gene fimA, while upregulating the transcription of c-di-GMP-related genes (pdeR, pdeA, and dosP). It is noteworthy that FA exhibits significant synergistic antibacterial effects when combined with clinically commonly used antibiotics, including sodium fosfomycin, ceftriaxone, gentamicin, and tetracycline, with the most prominent synergistic effect observed in the combination of FA and sodium fosfomycin. These results confirm that FA possesses notable anti-biofilm activity and novel synergistic antibacterial properties, providing a potential therapeutic strategy for treating E. coli infections. Full article

Streptococcus mutans (S. mutans) is a cariogenic bacterium in the oral cavity that plays a significant role in plaque formation and dental caries. In previous research by our group, we showed that the endocannabinoid anandamide (AEA) has anti-bacterial and anti-biofilm activities against S. mutans. Here, we aimed to investigate its effects on S. mutans through metabolomics analyses. S. mutans was cultivated in the absence or presence of AEA at a sub-minimum inhibitory concentration (MIC), and changes in metabolites and metabolic pathways were assessed through liquid chromatography–mass spectrometry (LC-MS). Treatment of S. mutans using AEA at 10 µg/mL significantly disturbed the glycolytic flux in the bacteria, which was indicated by a reduced glucose uptake into the cell, suppression of key glycolytic intermediates, reduced acid production into the media, imbalance of NAD⁺/NADH, and decreased adenosine triphosphate (ATP) production. The disruption of carbohydrate metabolism impacts critical cellular processes, including energy production, redox balance, and biosynthetic pathways, leading to metabolic stress and impaired cellular function. These results highlight the mode of action of AEA as an antimicrobial agent. Altogether, these findings suggest that AEA has potential as a novel antimicrobial agent in the development of therapeutics against S. mutans. Full article

Background/Objectives: Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections in both community and hospital settings worldwide. Antimicrobial-resistant UPEC strains pose a significant challenge for effective antibiotic therapy. In this study, 50 bacterial isolates recovered from urine samples of patients attended in different sectors of a public hospital in Rio de Janeiro over five months were analyzed to assess antimicrobial resistance and virulence profiles through broad gene screening. Methods: Biofilm production was assessed using a semi-quantitative adherence assay. PCR was employed to investigate 27 resistance genes, 6 virulence genes, sequence types (STs), and phylogroups. Susceptibility to 25 antimicrobial agents was determined by disk diffusion testing. Furthermore, the pathogenic potential was evaluated in vivo using the Tenebrio molitor larvae infection model. Results: Most UPEC isolates were moderate or strong biofilm producers (41/50; 82%). The sul1 and sul2 resistance genes were the most frequently detected (58%). Two virulence gene patterns were identified: fyuA, iutA, fimH, cnf1 and fyuA, iutA, fimH (13 isolates; 26%). ST131 and ST73 were the most common sequence types (16% each), and phylogroup B2 was the most prevalent (50%). Thirty isolates (60%) were multidrug-resistant, most of which belonged to phylogroup B2. UPEC exhibited dose-dependent lethality, causing 100% mortality at 2.6 × 10⁸ CFU/mL within 24 h. Conclusions: These findings reinforce the urgent need for surveillance strategies and effective antimicrobial stewardship in clinical practice. Full article

This study evaluated the effectiveness of individual clean-in-place (CIP) steps in removing biofilms from reverse osmosis (RO) membranes under dynamic flow conditions using the Centers for Disease Control (CDC) biofilm reactor. Biofilms were developed in the laboratory under continuous flow, using mixed-species bacterial isolates obtained from 10-month-old RO membrane biofilms from a commercial facility. Individual CIP chemicals, representative of those used in commercial protocols, were tested against 24 h-old biofilms. Additionally, a complete six-step sequential CIP process was conducted under dynamic conditions, consisting of treatments with alkali, surfactant, acid, enzyme, a secondary surfactant, and sanitizer. All experiments were performed in quadruplicate, and data were subjected to statistical analysis. Among individual treatments, the acid step was the most effective, significantly outperforming the other CIP cleaning steps by reducing bacterial counts from 5.62 to 4.10 log units, a 96.98% reduction. The full six-step CIP protocol reduced counts to 2.24 log units, indicating the persistence of resistant cells. The presence of viable cells post-treatment highlights the limited efficacy of the tested CIP chemicals in fully eradicating mature biofilms. Additionally, skipping any step in the membrane cleaning can significantly compromise the efficiency and performance during production. These findings suggest that biofilms grown in vitro under dynamic conditions using the CDC reactor exhibit a more robust assessment of the CIP treatments in accomplishing the biofilm control. This study highlights the need for optimized, scientifically validated CIP protocols targeting biofilms to improve cleaning efficacy and food safety. Full article

Background: Helicobacter pylori (H. pylori) is a major pathogen associated with a variety of gastrointestinal disorders, including gastritis, peptic ulcers, and gastric cancer. As a natural bioactive product, propolis exhibits multifaceted and multi-mechanistic effects. Due to its immunomodulatory, anti-inflammatory, and antioxidant properties, propolis has emerged as a promising therapeutic alternative, offering an innovative approach to managing H. pylori infections and providing new insights into addressing antibiotic resistance. Methods: This comprehensive review, synthesizing data from PubMed, ScienceDirect, and SciFinder, examines the mechanisms by which propolis combats H. pylori. Results: Propolis has demonstrated significant antibacterial efficacy against H. pylori in both in vitro and in vivo models. Its multitargeted mechanisms of action include direct inhibition of bacterial growth, interference with the expression of virulence factors, suppression of virulence-associated enzymes and toxin activity, immunomodulation, and anti-inflammatory effects. These combined actions alleviate gastric mucosal inflammation and damage, reduce bacterial colonization, and promote mucosal healing through antioxidant and repair-promoting effects. Furthermore, propolis disrupts oral biofilms, restores the balance of the oral microbiome, and exerts bactericidal effects in the oral cavity. Synergistic interactions between propolis and conventional medications or other natural agents highlight its potential as an adjunctive therapy. Conclusions: Propolis demonstrates dual functionality by inhibiting the release of inflammatory mediators and suppressing H. pylori growth, highlighting its potential as an adjuvant therapeutic agent. However, clinical translation requires standardized quality control and higher-level clinical evidence. Future research should focus on validating its clinical efficacy and determining optimal dosing regimens, and exploring its role in reducing H. pylori recurrence. Full article

Understanding the spatiotemporal dynamics of water quality parameters and microbial communities in drinking water distribution systems (DWDS) and their interrelationships is critical for ensuring the safety of tap water supply. This study investigated the diurnal, monthly, and annual variation patterns of water quality and the stage-specific succession behaviors of microbial communities in a DWDS located in southeastern China. Results indicated that hydraulic shear stress during peak usage periods drove biofilm detachment and particle resuspension. This process led to significant diurnal fluctuations in total cell counts (TCC) and metal ions, with coefficients of variation ranging from 0.44 to 1.89. Monthly analyses revealed the synergistic risks of disinfection by-products (e.g., 24.5 μg/L of trichloromethane) under conditions of low chlorine residual (<0.2 mg/L) and high organic loading. Annual trends suggested seasonal coupling: winter pH reductions correlated with organic acid accumulation, while summer microbial blooms associated with chlorine decay and temperature increase. Nonlinear interactions indicated weakened metal–organic complexation but enhanced turbidity–sulfate adsorption, suggesting altered contaminant mobility in pipe scales. Microbial analysis demonstrated persistent dominance of oligotrophic Phreatobacter and prevalence of Pseudomonas in biofilms, highlighting hydrodynamic conditions, nutrient availability, and disinfection pressure as key drivers of community succession. These findings reveal DWDS complexity and inform targeted operational and microbial risk control strategies. Full article

Background: Antimicrobial resistance is a major global health threat, particularly from pathogens such as Pseudomonas aeruginosa, known for forming biofilms and producing virulence factors that cause persistent infections. Essential oils (EOs) offer promising alternatives to conventional antimicrobial therapy due to their antimicrobial and antibiofilm properties. This study aimed to investigate the modulatory effects of a thymol-rich EO from Satureja montana L. on planktonic growth, biofilm formation, swarming motility, proteolytic activity and pyocyanin production of P. aeruginosa PAO1. Methods: The essential oil, isolated by hydrodistillation from S. montana aerial parts, was analysed by GC-MS. The minimum inhibitory concentration (MIC) of the EO and thymol was determined using the broth microdilution method. Sub-MICs were tested for planktonic growth and biofilm formation. Virulence was assessed by testing swarming motility, proteolytic activity and pyocyanin production. Results: The EO was characterised by a very high content of monoterpenes, with thymol dominating (56.47%). MIC for both EO and thymol was 4 mg/mL. They showed a biphasic effect: higher concentrations significantly inhibited planktonic growth (36–58% reduction; p < 0.05), while lower concentrations promoted it (10–17% increase; p < 0.05). Biofilm biomass varied, but the biofilm index indicated promotion at higher concentrations (0.125–0.5 mg/mL; p < 0.05). Both inhibited swarming at 0.5 mg/mL (thymol was more effective). Thymol decreased proteolytic activity, while EO increased pyocyanin production. Conclusions: S. montana essential oil and thymol show concentration-dependent modulation of P. aeruginosa growth, biofilms and virulence, suggesting their potential as anti-virulence agents, although the biphasic responses require careful dosing. Full article

Thermo-tolerance is a virulence factor responsible for the emergence of new fungal pathogens, including Candidozyma auris (formerly classified as Candida auris, C. auris). It has been shown that in C. auris the thermo-tolerance, as well as other virulence traits, such as the ability to aggregate, to form pseudo-hyphae, or to produce melanin are strain-specific features. Here, we investigated the impact of different temperatures (25 °C, 37 °C and 42 °C) on the phenotypic and virulence profile of C. auris strain CDC B11903. The results show a positive correlation between the resistance to antifungals and increasing temperature from 25 °C to 37 °C, while no differences were observed between 37 °C and 42 °C, except for Anidulafungin. Furthermore, C. auris growth was impaired at 25 °C as compared to 37 °C and 42 °C. Except for the haemolytic activity, which increased with rising temperatures, phospholipase, lipase and biofilm production were found at all tested temperatures. Moreover, the ability to produce melanin was observed only at 37 °C and 42 °C. The capacity to grow as pseudo-hyphae or in clusters and to adhere to both biotic and abiotic surfaces were observed at all the temperatures tested, with increased propensity of C. auris to adhere to abiotic surfaces with rising temperatures. The results underline the thermo-tolerance of C. auris strain B11903 and its increased virulence profile at human body temperature both in physiological (37 °C) and febrile state (42 °C). Full article

Background and purpose: Vulvovaginal candidiasis (VVC), caused by Candida albicans (C. albicans), is exacerbated by oxidative stress and uncontrolled inflammation. Pathogens like C. albicans generate reactive oxygen species (ROS) to enhance virulence, while host immune responses further amplify oxidative damage. This study investigates the antioxidant and antifungal properties of Hyssopus cuspidatus Boriss volatile extract (SXC), a traditional Uyghur medicinal herb, against fluconazole-resistant VVC. We hypothesize that SXC’s bioactive volatiles counteract pathogen-induced oxidative stress while inhibiting fungal growth and inflammation. Methods: GC-MS identified SXC’s major bioactive components, while broth microdilution assays determined minimum inhibitory concentrations (MICs) against bacterial/fungal pathogens, and synergistic interactions with amphotericin B (AmB) or fluconazole (FLC) were assessed via time–kill kinetics. Anti-biofilm activity was quantified using crystal violet/XTT assays, and in vitro studies evaluated SXC’s effects on C. albicans-induced cytotoxicity (LDH release in A431 cells) and inflammatory responses (cytokine production in LPS-stimulated RAW264.7 macrophages). A murine VVC model, employing estrogen-mediated pathogenesis and intravaginal C. albicans challenge, confirmed SXC’s in vivo effects. Immune modulation was assessed using ELISA and RT-qPCR targeting inflammatory and antioxidative stress mediators, while UPLC-MS was employed to profile metabolic perturbations in C. albicans. Results: Gas chromatography-mass spectrometry identified 10 key volatile components contributing to SXC’s activity. SXC exhibited broad-spectrum antimicrobial activity with MIC values ranging from 0.125–16 μL/mL against bacterial and fungal pathogens, including fluconazole-resistant Candida strains. Time–kill assays revealed that combinations of AmB-SXC and FLC-SXC achieved sustained synergistic bactericidal activity across all tested strains. Mechanistic studies revealed SXC’s dual antifungal actions: inhibition of C. albicans hyphal development and biofilm formation through downregulation of the Ras1-cAMP-Efg1 signaling pathway, and attenuation of riboflavin-mediated energy metabolism crucial for fungal proliferation. In the VVC model, SXC reduced vaginal fungal burden, alleviated clinical symptoms, and preserved vaginal epithelial integrity. Mechanistically, SXC modulated host immune responses by suppressing oxidative stress and pyroptosis through TLR4/NF-κB/NLRP3 pathway inhibition, evidenced by reduced caspase-1 activation and decreased pro-inflammatory cytokines (IL-1β, IL-6, TNF-α). Conclusions: SXC shows promise as a broad-spectrum natural antimicrobial against fungal pathogens. It inhibited C. albicans hyphal growth, adhesion, biofilm formation, and invasion in vitro, while reducing oxidative and preserving vaginal mucosal integrity in vivo. By disrupting fungal metabolic pathways and modulating host immune responses, SXC offers a novel approach to treating recurrent, drug-resistant VVC. Full article

Background/Objectives: Yersinia enterocolitica is a pathogenic bacterium that forms biofilms, enhancing its persistence and resistance to antimicrobial agents. Biofilm formation in Y. enterocolitica is influenced by environmental factors such as temperature, calcium, and the presence of the virulence plasmid pYV. This study aims to explore how temperature, calcium, and pYV modulate biofilm formation in Y. enterocolitica, with a focus on motility and extracellular polymeric substance (EPS) production as key factors. Methods: Y. enterocolitica strains with and without the pYV plasmid were cultured at two different temperatures (26 °C and 37 °C). The effect of calcium (5 mM) on biofilm formation was tested at both temperatures. Biofilm formation was measured using crystal violet staining, motility was assessed using soft agar plates, and EPS production was quantified to determine its role in biofilm stabilization. Results: At 26 °C, biofilm formation increased in pYV-negative strains, driven primarily by motility and flagellar expression. In contrast, at 37 °C, pYV-positive strains showed strong biofilm formation despite reduced growth, with EPS production as the key stabilizing factor. Calcium modulated biofilm formation in a temperature-dependent manner: at 26 °C, 5 mM calcium modestly reduced biofilm formation in pYV-negative strains, while at 37 °C, it significantly suppressed both EPS production and biofilm formation by approximately 50% in pYV-positive strains. Conclusions: This study reveals a novel regulatory switch where temperature, calcium, and pYV modulate biofilm formation in Y. enterocolitica. These findings suggest that Y. enterocolitica can adapt between motility- and EPS-dominated biofilm strategies depending on environmental conditions. Understanding these mechanisms offers potential targets for controlling biofilm-related persistence in clinical and food safety contexts. Full article

Micro-organisms are abundant in nature and can also be found in hospital settings, causing high rates of infections. This study aimed to identify bacteria isolated from a veterinary hospital, as well as to perform antimicrobial susceptibility testing using the disk diffusion method (Kirby–Bauer), biofilm production tests using 96-well polystyrene microtiter plates and crystal violet dye, and genetic analysis of the ica operon of Staphylococcus isolates. Three collections were made from eleven surfaces and objects in the hospital’s non-critical areas (general areas) and critical areas (surgical center), totaling thirty-three samples. A total of 66 different bacterial isolates were obtained, with 77% (51/66) Gram-positive and 23% (29/66) Gram-negative. Resistance profiles were found for multidrug-resistance (MDR), methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE), and other unidentified species of methicillin-resistant coagulase-negative (MRCNS) and extended-spectrum beta-lactamase (ESBL), as well as biofilm production rates of 57% (38/66) of the isolates. Analysis of the operon genes for Staphylococcus sp. showed divergence in some samples when compared to the phenotypic test performed. In summary, there is a high presence of micro-organisms with resistance and virulence factors spread throughout the various areas of the veterinary hospital. Full article

Toxicological effects of microplastics (MPs) have been confirmed in a variety of microorganisms in aquatic environments, and they are closely correlated with the physicochemical properties of the MPs. In a natural environment, different aging treatments always induce different alterations in the physicochemical properties of MPs, thus influencing their environmental behaviors and biotoxicity. In this work, physicochemical properties and toxicity towards Escherichia coli (E. coli) were investigated in polystyrene (PS) MPs (3 and 10 μm) before and after aging by UV irradiation and biofilm formation, respectively. The results show that UV irradiation and biofilm formation led to different alterations in the surface morphologies and functional groups of PS. The UV-aged 3 μm PS had the strongest inhibitory effect on E. coli growth, and the bio-aged 10 μm PS had the strongest beneficial effect on E. coli growth. Also, the ATPase activity, production of intercellular ROS, and MDA content of the E. coli were affected differently. UV aging enhanced the toxicity of PS towards E. coli, while bio-aging had an opposite weakening effect. Overall, our research verified the remarkable differences in the physicochemical properties and biotoxicity of PS induced by UV aging and bio-aging. Full article

Recurrent urinary tract infections (UTIs) pose a significant clinical challenge in both human and veterinary medicine, due to antibiotic-resistant and biofilm-forming bacteria. We hypothesized that high glucose levels in diabetic animals enhance biofilm formation and reduce antibiotic efficacy, promoting infection persistence. This study analyzed Escherichia coli from a diabetic female Labrador Retriever with recurrent UTIs over 18 months, focusing on antimicrobial resistance, biofilm-forming capacity, and genomic characterization. Most isolates (9/11) were resistant to ampicillin and fluoroquinolones. Whole genome sequencing of six selected isolates revealed that they belonged to the multidrug-resistant ST1193 lineage, a globally emerging clone associated with persistent infections. Phylogenetic analysis revealed clonal continuity across six UTI episodes, with two distinct clones identified: one during a coinfection in the second episode and another in the last episode. High-glucose conditions significantly enhanced biofilm production and dramatically reduced antibiotic susceptibility, as evidenced by a marked increase in minimum biofilm inhibitory concentrations (MBICs), which were at least 256-fold higher than the corresponding minimum inhibitory concentration (MIC). Sulfamethoxazole–trimethoprim demonstrated the strongest antibiofilm activity, though this was attenuated in glucose-supplemented environments. This research highlights the clinical relevance of glucosuria in diabetic patients and emphasizes the need for therapeutic strategies targeting biofilm-mediated antibiotic tolerance to improve the management of recurrent UTIs. Full article

Background: Four of the six ESKAPE pathogens are responsible for a majority of antimicrobial resistance (AMR)-related deaths worldwide. Identifying the pathogens that evade antibiotic treatments more efficiently than others can help diagnose pathogens requiring more attention. The study was thus designed to evaluate the biofilm and resistance properties of five ESKAPE pathogens comparatively. A total of 165 clinical isolates of 5 ESKAPE pathogen species (E. faecium, S. aureus, K. pneumoniae, A. baumannii, and P. aerurginosa) were collected from a tertiary hospital in Bangladesh. Methodology: Following secondary identification, antibiotic susceptibility was determined by the disc diffusion method and minimum inhibitory concentration. The biofilm formation was determined by the microtiter plate biofilm formation assay. The biofilm-forming genes were screened by PCR. Detection of carbapenemase and Metallo-β-lactamase was performed by the modified carbapenem inactivation method (mCIM) and the EDTA-modified carbapenem inactivation method (eCIM) test, respectively. Results: Among Gram-positive isolates, E. faecium exhibited higher multi-drug resistance (MDR) rates (90%) compared to S. aureus (10%). In Gram-negative isolates, A. baumannii and K. pneumoniae showed elevated resistance to carbapenems (74.29% and 45.71%, respectively), cephalosporins, and β-lactam inhibitors, while P. aeruginosa demonstrated relatively lower resistance. Colistin resistance was highest in K. pneumoniae (42.86%). Biofilm formation was prevalent, with 88.5% of isolates forming biofilms, including 15.8% strong biofilm producers. Notably, K. pneumoniae and A. baumannii exhibited higher biofilm-forming capabilities compared to P. aeruginosa. A significant correlation was observed between biofilm formation and resistance to carbapenems, cephalosporins, and piperacillin/tazobactam (p < 0.05), suggesting a potential role of biofilms in disseminating resistance to these antibiotics. Carbapenemase production was detected in 23.8% of Gram-negative isolates, with K. pneumoniae showing the highest prevalence (34.3%). Additionally, 45.8% of carbapenemase producers expressed Metallo-β-lactamases (MBLs). Among S. aureus isolates, 46.7% carried the mecA gene, confirming methicillin resistance (MRSA), while 20% of E. faecium isolates exhibited vancomycin resistance, primarily mediated by the vanB gene. Conclusions: These findings can help pinpoint the pathogens of significant threat. Full article