Search Results (1,173)

Serratia marcescens has emerged as an important opportunistic pathogen in intensive care units (ICUs), where critically ill patients, invasive devices, antimicrobial exposure, and complex environmental reservoirs create favorable conditions for colonization, infection, and recurrent outbreaks. This narrative review synthesizes evidence from the past decade regarding the clinical and molecular epidemiology, environmental persistence, device-associated transmission, biofilm-mediated resistance, and infection-control strategies of S. marcescens in ICU settings. The literature was reviewed using an integrative approach informed by Ferrari’s narrative review framework, with thematic synthesis across clinical, microbiological, environmental, and genomic domains. Recent evidence indicates that ICU-associated S. marcescens infections frequently involve respiratory tract colonization, ventilator-associated pneumonia, bloodstream infection, urinary tract infection, and device-related transmission. Hospital water systems, sink drains, wet surfaces, ventilator circuits, reusable equipment, and contaminated antiseptic or liquid products may serve as persistent reservoirs, particularly when biofilm formation supports long-term survival and recurrent dissemination. At the molecular level, S. marcescens demonstrates substantial genomic diversity, intrinsic and acquired antimicrobial resistance, inducible AmpC β-lactamase activity, efflux-mediated tolerance, and plasmid-associated resistance gene transfer. This review particularly emphasizes the molecular determinants that enable S. marcescens to persist in ICU ecosystems, including AmpC-mediated β-lactam resistance, efflux-associated tolerance, quorum-sensing-regulated biofilm formation, plasmid-mediated horizontal gene transfer, and WGS-defined clonal transmission. Whole-genome sequencing, rapid molecular diagnostics, active surveillance, environmental sampling, and integrated infection-control bundles have become increasingly important for distinguishing clonal outbreaks from endemic transmission and guiding timely interventions. Emerging perspectives emphasize the need to combine antimicrobial stewardship, environmental engineering, respiratory-care auditing, anti-biofilm strategies, and AI-assisted real-time surveillance into adaptive ICU infection-control frameworks. Overall, S. marcescens should be regarded not merely as an episodic outbreak organism, but as a highly adaptable ICU-associated pathogen requiring multidisciplinary prevention strategies. Full article

Background: Urosepsis is a life-threatening condition accounting for approximately 20–30% of all sepsis cases and typically arises from ascending infection by uropathogenic Escherichia coli (UPEC). Disease progression is mediated by virulence factors, including adhesins, iron acquisition systems, and toxins. Among these, P fimbriae, particularly papGII adhesin subunit, have been implicated in the transition from uncomplicated urinary tract infection (UTI) to severe urosepsis. This study aimed to evaluate whether papGII carriage, alone or in combination with other UPEC virulence determinants and clinical risk factors, can predict urosepsis. Methods: A total of 60 paired Escherichia coli isolates from concurrent blood and urine samples of adults with clinical sepsis were collected between January and June 2024. Control isolates were obtained from patients with cystitis (n = 28) and pyelonephritis (n = 32). Polymerase chain reaction (PCR) assays were used to detect fifteen virulence-associated genes, including the pap operon (with papG allelic variants), the type 1 fimbriae (fimH), S fimbriae (sfaS), curli fimbriae (csgA), afa/Dr adhesin operon genes, cytotoxic necrotizing factor 1 (cnf1), and the aerobactin biosynthesis (iucD) and receptor (iutA) genes. Associations between gene carriage and clinical groups were analyzed using chi-square tests. Results: The incidence of urosepsis increased with age, peaking in the 60–69-year age group. Renal disease and catheterization were identified as significant risk factors (p < 0.05). More than 95% of UPEC isolates carried the csgA gene associated with biofilm formation and the iucD gene. The α- hemolysin toxin (hlyA) was significantly associated with urosepsis [X²(1, N = 120) = 6.62, p = 0.03]. No significant differences were observed in the carriage of papA, papC, or fimH. Although papGII was present in 65% of urosepsis-associated UPEC isolates, it did not demonstrate a statistically significant independent association with urosepsis [p = 0.1]. Conclusion: This study demonstrates that while papGII may contribute to the pathogenic potential of UPEC and facilitate systemic infection, it is not a reliable independent predictor of urosepsis. Full article

Background/Objectives: This prospective observational cohort study aimed to evaluate the influence of heated tobacco (HT) and electronic cigarettes (ECs) on bone remodeling markers such as receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG), and periodontal status, at baseline and at 3 months after initial periodontal therapy. Methods: The sample comprised 236 participants (130 women, 106 men; mean age 38.96 ± 7.69 years), distributed across non-smokers (n = 72), heated tobacco/HT product users (n = 83), and electronic cigarette/EC users (n = 81). For each patient, the periodontal charting included periodontal probing depth (PPD), bleeding on probing (BOP), and clinical attachment loss (CAL). Unstimulated saliva samples were analyzed for RANKL and OPG levels. All patients underwent nonsurgical periodontal therapy (scaling and root planing). Between-group comparisons were performed using the Kruskal–Wallis test followed by Bonferroni-adjusted pairwise comparisons, while within-group changes over time were assessed using the Wilcoxon signed-rank test. To complement the primary nonparametric analyses, two-way mixed-design ANOVA and ANCOVA models adjusted for baseline values and periodontitis stage were performed as sensitivity analyses. Statistical significance was set at p < 0.05. Results: At baseline, both product user groups exhibited significantly higher PPD (p = 0.005) and CAL (p = 0.001) compared with non-smokers, with no differences between HT and EC users. Salivary RANKL levels were significantly higher in HT and EC users than in non-smokers, and OPG levels did not differ significantly. Following non-surgical periodontal therapy, all parameters improved significantly across groups (p < 0.001). At the 3-month follow-up, both product user groups maintained higher PPD (p = 0.008), CAL (p = 0.001), and salivary RANKL levels, compared with non-smoking individuals (p < 0.001). The RANKL/OPG ratio remained significantly different only for EC users compared with non-smokers (p < 0.001). Conclusions: HT and EC use were associated with differences in periodontal parameters and higher RANKL levels, while differences in the RANKL/OPG ratio were observed in EC users compared with non-smokers. Non-surgical periodontal therapy improved clinical parameters and reduced the RANKL/OPG ratio, highlighting the importance of biofilm control. Full article

A 700 m pilot-scale cast iron pipeline reactor was operated for 120 days to investigate corrosion-stage evolution under reclaimed-water conveyance conditions. Sampling points were arranged at 50, 250, 450, and 650 m, and water-quality monitoring, coupon weight-loss tests, scanning electron microscopy (SEM), and high-throughput 16S rRNA sequencing were combined to characterize corrosion-rate variation, corrosion-product morphology, and microbial community succession. During transport, NH₄⁺ generally decreased while NO₃⁻ increased, indicating nitrification-related nitrogen transformation under aerobic conditions; meanwhile, PO₄³⁻ declined and DOC fluctuated, reflecting coupled physicochemical and biological processes. SEM observations showed a transition from loose porous deposits to relatively compact layered corrosion products, followed by local deterioration and renewed porous structures in the later period. The corrosion rate followed an increase–decrease–re-increase pattern rather than a monotonic trend. Therefore, corrosion acceleration (CA = dc/dt) was introduced as an auxiliary diagnostic indicator to identify whether corrosion activity was increasing, decreasing, or temporarily stabilizing. Microbial community analysis showed stage-associated variation in biofilm and nitrogen-transformation-related taxa, supporting the interpretation that corrosion evolution was jointly affected by water-quality change, corrosion-product development, and microbial succession. Overall, the combined interpretation of corrosion rate, CA, water quality, SEM morphology, and microbial succession provides a more informative basis for diagnosing corrosion-stage transitions in reclaimed-water cast iron pipelines. From a sustainability perspective, this diagnostic framework can support long-term operation, maintenance planning, and risk monitoring of urban reclaimed-water distribution infrastructure, thereby improving pipeline durability, reducing leakage and maintenance risks, and enhancing the reliability of reclaimed-water reuse systems. Full article

Rivers have always been essential to humankind. They are used for many purposes and, as a result, have been heavily modified. Human impacts, many of them still poorly understood, interfere with river ecosystems, making them vulnerable to disturbances. Amongst these, mega events along riverbanks are listed. We studied the effects of the “FM4 Frequency Festival,” which attracted more than 200,000 visitors, on microalgae in the channelized section of the River Traisen in St. Pölten, the capital of Lower Austria. During the festival, phosphorus, dissolved organic carbon, and chloride increased significantly during the whole study period compared with before and after. Although the overall epilithic biomass remained unchanged during the festival period, the phytobenthos community experienced an increase in taxonomic richness downstream of the festival area. Both the Shannon diversity (mean ± SD = 2.89 ± 0.34) and Pielou’s evenness (mean ± SD = 0.73 ± 0.08) did not differ significantly between the sampling dates before, during, and after the festival. We found a shift towards Achnanthidium minutissimum as the dominant species during the festival. Diatoma ehrenbergii, which is sensitive to nutrient enrichment and organic pollution, disappeared during the event. Overall, the biofilm shifted towards a community dominated by heterotrophs during the festival, likely due to high organic loading. Pelagic microalgae experienced a rise in the total taxa number during the festival, which was partly caused by resuspension of phytobenthos. Our results reflect significant impacts from visitors to the Traisen ecosystem. Not only short-term changes in the hydrochemical environment but also mechanical disturbances of the phytobenthos caused by visitors were demonstrated. We suggest continuous monitoring to verify that such events will not have long-term impacts on the system. Full article

Background: Dental caries is a chronic disease mediated by biofilm, which is caused by Streptococcus mutans, and enamel genetics modulates susceptibility. The variants of ENAM might alter the adhesion of enamel and bacteria. One important anti-viral target is sortase A (SrtA), which restricts colonization but does not have an impact on bacterial survival. Aim: The aim of this study was to find out the relationship between ENAM rs3796704 and dental caries vulnerability among adult Iraqi Arab females and to assess the antibiofilm capacity of eugenol and cinnamic acid against S. mutans SrtA using molecular docking, ADMET prediction, and molecular dynamics modeling. Methods: A case–control study was done on 240 women (aged 25–30 years; 120 caries, 120 controls). HRM real-time PCR was done to genotype ENAM rs3796704. An analysis of allelic and genotypic distributions was done using chi-square tests and odds ratios (p < 0.05). An in silico docking analysis aimed at SrtA (PDB: 4TQX) was performed in AutoDock Vina, and this was followed by ADMET profiling and a 50 ns molecular dynamics simulation (OPLS4/TIP3P, NPT 300 K/1 atm). Results: The level of the G allele was found to be lower in the cases than in the controls (60% vs. 70; OR = 0.6429; p = 0.02), but the level of the A allele was found to be higher in the cases (40% vs. 30; OR = 1.5556; p = 0.02). Docking showed a minor difference in binding affinities with eugenol (−4.961 kcal/mol) and cinnamic acid (−4.939 kcal/mol) as compared with chlorhexidine (−4.692 kcal/mol). Both compounds showed stable binding for more than 50 ns as well as desirable predicted pharmacokinetics. Conclusions: The caries vulnerability in this sample was associated with ENAM rs3796704. Eugenol and cinnamic acid undergo stable dissociative interactions with SrtA and were found to have favorable safety profiles in silico. Therefore, they may be considered as adjunctive anti-virulence agents in the prevention of caries. Full article

Ornamental fountains in the Alhambra and Generalife (Granada, Spain) constitute complex socio-ecological systems where water, stone, and biological communities interact, making them highly vulnerable to biodeterioration caused by phototrophic microorganisms such as cyanobacteria, green algae, and diatoms. Conventional chemical biocides, although widely applied, present significant drawbacks including toxicity, material degradation, ecological imbalance, and limited long-term effectiveness. In this context, this study evaluated the potential of algicidal bacteria as a sustainable alternative for controlling phototrophic growth in heritage environments. Water samples from eight ornamental fountains were analyzed using 16S ribosomal RNA (16S rRNA) gene sequencing to characterize bacterial communities and identify taxa previously reported with algicidal activity. Statistical analyses were conducted to assess relationships between microbial community structure and biofilm development. In parallel, functional screening assays using filtered fountain waters against Chlorella vulgaris were performed to evaluate intrinsic inhibitory capacity. The most active sample was selected for bacterial isolation and further validation through co-culture assays, cell density measurements, and pulse-amplitude-modulated (PAM) fluorometry. A total of 18 genera with reported algicidal capacity were detected, representing a substantial fraction of the microbiome across all samples. However, no significant association was found between these taxonomic metrics and biofilm development, highlighting a decoupling between taxonomic composition and functional activity. The most active isolate, identified as Stenotrophomonas maltophilia strain LIG25, caused a rapid decline in photosynthetic efficiency and achieved more than 98% inhibition of algal growth. These findings demonstrate that ornamental fountain microbiomes represent a reservoir of native biocontrol agents and support the development of eco-friendly strategies for cultural heritage conservation. Full article

Chinese Cordyceps (Ophiocordyceps sinensis) and Xinjiang Cordyceps (Paraisaria gracilis) are related entomopathogenic fungi that occupy different elevations and habitats. Whether their holobiont architectures have diverged accordingly is unknown. In this hypothesis-generating study based on samples from single locations (Altai Mountains for Xinjiang Cordyceps and Nagqu, Tibet for Chinese Cordyceps), we compared the two species using amplicon sequencing, untargeted metabolomics, and comparative genomics. Chinese Cordyceps from the sampled site comprises a specialized parasitic fungus and host-adapted bacteria for nutrient acquisition. Xinjiang Cordyceps from the Altai site contains diverse saprotrophic fungi and a rhizosphere-like bacterial consortium enriched in oxidative defense and biofilm genes, a finding that may explain why its sclerotia remain intact for 3–5 years in this population. Metabolomic profiles distinguish the two species at these sites. Xinjiang Cordyceps shows upregulation of tyrosine and porphyrin pathways, and its bacterial community shows functional enrichment in the same pathways, suggesting cross-kingdom coordination. P. gracilis has lost many gene families, and the retained species-specific genes are linked to cell adhesion and acyltransferase activity. Xinjiang Cordyceps is not a simple substitute for Chinese Cordyceps but appears to represent a different ecological strategy shaped by genome streamlining and host–microbe coadaptation. Our findings generate testable hypotheses for future large-scale, multi-population investigations. Full article

Introduction/Objectives: Dental caries is a significant public health burden in Brazil, with regional disparities deeply affecting children in the North and Northeast. This study assessed the prevalence and severity of dental caries in preschool children from Balsas (MA) and investigated its association with fluoride concentrations in the public water supply. Methods: A cross-sectional study was conducted with 256 children (aged 3–5 years) enrolled in municipal schools. Schools were selected using a stratified sampling strategy based on the water network, with exposure validated via chemical analysis. Calibrated dentists performed examinations using the FOA-UNESP risk scale, assessing biofilm and gingivitis as objective clinical proxies for hygiene. Fluoride levels were analyzed using an ion-selective electrode. Statistical analysis included Fisher’s exact test, Kruskal–Wallis, and Multiple Correspondence Analysis (MCA). Results: Caries prevalence was 60.16%, with 41.8% of children in severe risk categories (F: 27.0%; G: 14.8%). Water analysis revealed universal hypofluoridation (0.02–0.34 µg F/mL). A significant association was found between residual fluoride (0.02 µg F/mL) and greater caries severity (p = 0.04). Poor hygiene markers (biofilm and gingivitis) were significantly associated with a higher number of decayed teeth (p < 0.05). MCA identified a cluster linking residual fluoridation to severe clinical conditions and social vulnerability. Conclusions: High caries prevalence associated with inadequate fluoridation highlights critical regional health inequalities in Balsas. These findings underscore the urgent need for policies ensuring universal water fluoridation and strengthening school-based preventive strategies to mitigate the impact of social determinants on child development. Full article

Periodontitis (P) and Type 2 Diabetes Mellitus (T2DM) are chronic inflammatory diseases that share pathophysiological pathways involving immune dysregulation and oxidative stress. Both conditions have been associated with increased susceptibility to viral infections, including SARS-CoV-2. In this regard, molecules associated with viral infection include angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2). This study aimed to evaluate the clinical periodontal status, oral microbiota composition, and the expression of ACE2 and TMPRSS2 in the oral epithelium and gingival tissue of patients with and without T2DM and P. Methods: This cross-sectional study enrolled 120 participants allocated into four groups based on periodontal and glycemic status: periodontally healthy non-diabetic individuals (PH non-T2DM), periodontitis without diabetes (P non-T2DM), periodontally healthy individuals with type 2 diabetes mellitus (PH T2DM), and periodontitis with T2DM (P T2DM), with 30 participants per group. Full-mouth clinical periodontal parameters were recorded by a calibrated examiner. Oral microbiota was assessed from unstimulated whole saliva, labial swab samples, and subgingival biofilm by selective culture and checkerboard DNA-DNA hybridization. Gingival exfoliative cytology and full-thickness gingival biopsies were obtained for immunohistochemical evaluation of ACE2 and TMPRSS2 expression. Cytomorphometric analysis and polymorphonuclear cell counts were performed on epithelial smears. Additionally, primary human gingival fibroblasts (HGFs) isolated from each group were stimulated with bacterial ligands (LPS, LTA, and PGN) to assess ACE2 and TMPRSS2 modulation by Western blot. Intergroup comparisons were performed using one-way ANOVA with Bonferroni post hoc correction and the Mann–Whitney U test, with statistical significance set at p < 0.05. Results: Diabetic patients exhibited higher plaque accumulation, clinical attachment loss, and bleeding on probing compared with non-diabetic individuals (p < 0.05). The diabetic groups showed significantly higher levels of Actinomyces, Fusobacterium, and Streptococcus spp., with decreased Staphylococcus counts. ACE2 and TMPRSS2 expression were markedly elevated in gingival epithelial cells of P T2DM patients, predominantly in basal and suprabasal layers. The nuclear-to-cytoplasmic ratio and polymorphonuclear cell counts were also increased in diabetic subjects. Conclusions: T2DM and P synergistically upregulate ACE2 and TMPRSS2 expression and alter the oral microbiota. Full article

Coagulase-negative staphylococci (CoNS) and mammaliicocci (MA) are common in food-derived samples and may act as antimicrobial resistance (AMR) reservoirs. A previous study reported a high S. aureus prevalence in poultry meat. The objective of this study was to characterize the species diversity, antimicrobial resistance, and biofilm-forming capacity of CoNS/MA from the same food samples. Species identification, antimicrobial susceptibility testing, resistance gene detection, molecular typing, and biofilm formation assays were performed. One hundred and forty-eight non-repetitive CoNS/MA isolates were detected in 85% of samples, and 14 species were identified. The most prevalent species were S. epidermidis (18.2%), S. simulans (12.8%), S. saprophyticus (12.2%), S. warneri (11.5%), and M. lentus (10.1%). Most samples harbored one or two different species, although some showed higher diversity. Although 27.0% of isolates were pan-susceptible, 22.3% were multidrug-resistant (MDR), significantly associated with M. lentus and S. epidermidis. Methicillin resistance was found in 10 isolates, mainly in S. epidermidis (lineages ST9, ST59, ST88 and ST640). Biofilm formation was observed in 24.3% of isolates (some of them MDR) and was significantly associated with S. pasteuri and S. xylosus and with samples from supermarkets. No methicillin-resistant isolates were biofilm producers. These findings highlight the diversity of CoNS/MA in poultry meat and their role as AMR reservoirs and persistence factors, emphasizing their relevance in food safety. Full article

The microbial community plays a crucial role in plant health and sustainable agricultural development by influencing plant physiology and development. This study aimed to explore the biocontrol potential of Bacillus subtilis A9, an endophytic bacterium isolated from Morchella sextelata, against rot disease caused by Lecanicillium aphanocladii. Metagenomic and metabolomic analyses were conducted on Morchella sextelata samples sprayed with B. subtilis A9 and a control group sprayed with LB medium. Metagenomic sequencing revealed that B. subtilis A9 significantly altered the microbial community structure and functional composition of Morchella sextelata, enriching genes related to biofilm formation, arginine and proline metabolism, and sulfur metabolism. Metabolomic analysis indicated significant upregulation of stress-resistant metabolites such as L-proline, ketoleucine, and pelargonic acid. Integrated multi-omics analysis demonstrated a strong correlation between the microbial community structure and the metabolomic profile, suggesting that B. subtilis A9 may be related to the disease-resistance response in the Morchella sextelata microecosystem. These findings provide a theoretical basis for the biological control of Morchella sextelata rot disease and support the development of green biocontrol strategies. Full article

Environmental biofilms are persistent structural components of livestock production systems and represent under-recognized drivers of pathogen persistence and antimicrobial resistance (AMR). This review examines the engineering, ecological, and operational factors that promote biofilm formation in dairy, poultry, and swine environments, with emphasis on drinking water distribution systems, feeding infrastructure, housing surfaces, and waste channels. Biofilms develop preferentially in low-shear zones, dead ends, and aging materials, where they enhance microbial tolerance to sanitation and facilitate horizontal gene transfer. Conventional monitoring approaches, largely based on planktonic sampling and single-time-point testing, underestimate attached biomass and fail to capture spatial heterogeneity. Although molecular and sensor-based technologies provide improved resolution, their farm-level implementation remains limited by cost, standardization challenges, and the absence of validated operational thresholds. Current EU surveillance frameworks focus primarily on antimicrobial use and resistance prevalence in animal isolates, while environmental compartments are rarely incorporated as monitored system elements. This review proposes a proportionate, risk-based approach that integrates existing farm data streams such as antimicrobial use metrics and biosecurity scoring systems with targeted environmental assessment of high-risk infrastructure. Mitigation strategies emphasize mechanical disruption, combined chemical sanitation, hydraulic optimization, material selection, and infrastructure lifecycle management. Embedding environmental biofilm control within existing engineering and stewardship frameworks supports more resilient, systems-based management of infectious and AMR risks in livestock production. Full article

Thermomineral springs provide stable thermal and geochemical regimes that promote the development of dense phototrophic biofilms dominated by cyanobacteria. Phototrophic communities were investigated across eight thermomineral springs in Serbia (six in eastern and two in central Serbia) using an integrated morphological, ecological, and molecular approach. Biofilms were sampled in 2024 from contrasting microhabitats (submerged, overflow, and splash/aerosol-exposed zones) and biomass was assessed through chlorophyll a (Chl a) quantification. Cyanobacterial taxa were identified via light microscopy using standard taxonomic keys and simple trichal morphotypes represented the highest diversity; Leptolyngbya showed the broadest distribution, while heterocytous taxa (Calothrix) were rare. A total of 73 cyanobacterial taxa were recorded across the eight investigated springs, with richness ranging from 1 to 33 taxa per locality; the highest richness was observed in Brestovac (33 taxa), followed by Šarbanovac (28) and Nikoličevo (22). Molecular characterization (16S rRNA) of nine cultured isolates revealed multiple filamentous cyanobacterial lineages, including Elainella (Oculatellales) and Wilmottia-related clades, while several isolates showed “Leptolyngbya-like” BLASTn affinities but phylogenetically separated clustering. Overall, the results indicate that Serbian thermomineral springs host diverse cyanobacteria-dominated biofilms shaped by local physical and chemical gradients and microhabitat structure and represent promising reservoirs of thermotolerant strains for further biotechnological use. Full article

Invasive fungal respiratory infections (IFRIs) remain a major cause of morbidity and mortality among immunocompromised patients, yet diagnosis continues to be hindered by nonspecific clinical features, limited sample accessibility, and the poor sensitivity or specificity of conventional tests. Microfluidic and microelectromechanical systems (MEMS)-based biosensing platforms have emerged as promising alternatives, enabling rapid, minimally invasive, and highly specific detection of fungal pathogens and host responses. Microfluidic nucleic acid and antigen assays allow on-chip amplification and immunodetection with reduced sample volumes and turnaround times, while CRISPR-enhanced systems further improve analytical sensitivity. Parallel advances in host response profiling—including transcriptomic, proteomic, and cytokine-based signatures—have demonstrated feasibility for integration into lab-on-a-chip platforms. MEMS-based technologies extend this potential by facilitating real-time analysis of exhaled volatile organic compounds, mechanical biosensing of fungal DNA and antigens, and in situ monitoring of device-associated biofilms. Translational studies highlight potential applications across intensive care, hematology–oncology, and transplant settings, as well as in outpatient monitoring of high-risk populations. However, several challenges remain, including limited multicenter validation, matrix-related biofouling effects, and a lack of standardization in fungal biomarker panels. Future directions include AI-driven interpretation of multianalyte data, multiplexed integration of host and pathogen markers, and development of fully cartridge-based systems for near-patient deployment. Collectively, these innovations may shift fungal diagnostics toward earlier, more precise, and patient-tailored interventions, improving outcomes in vulnerable populations. Full article