Search Results (23,415)

This review explores the biofilm architecture and drug resistance of Enterococcus faecalis in clinical and environmental settings. The biofilm in E. faecalis is a heterogeneous, three-dimensional, mushroom-like or multilayered structure, characteristically forming diplococci or short chains interspersed with water channels for nutrient exchange and waste removal. Exopolysaccharides, proteins, lipids, and extracellular DNA create a protective matrix. Persister cells within the biofilm contribute to antibiotic resistance and survival. The heterogeneous architecture of the E. faecalis biofilm contains both dense clusters and loosely packed regions that vary in thickness, ranging from 10 to 100 µm, depending on the environmental conditions. The pathogenicity of the E. faecalis biofilm is mediated through complex interactions between genes and virulence factors such as DNA release, cytolysin, pili, secreted antigen A, and microbial surface components that recognize adhesive matrix molecules, often involving a key protein called enterococcal surface protein (Esp). Clinically, it is implicated in a range of nosocomial infections, including urinary tract infections, endocarditis, and surgical wound infections. The biofilm serves as a nidus for bacterial dissemination and as a reservoir for antimicrobial resistance. The effectiveness of first-line antibiotics (ampicillin, vancomycin, and aminoglycosides) is diminished due to reduced penetration, altered metabolism, increased tolerance, and intrinsic and acquired resistance. Alternative strategies for biofilm disruption, such as combination therapy (ampicillin with aminoglycosides), as well as newer approaches, including antimicrobial peptides, quorum-sensing inhibitors, and biofilm-disrupting agents (DNase or dispersin B), are also being explored to improve treatment outcomes. Environmentally, E. faecalis biofilms contribute to contamination in water systems, food production facilities, and healthcare environments. They persist in harsh conditions, facilitating the spread of multidrug-resistant strains and increasing the risk of transmission to humans and animals. Therefore, understanding the biofilm architecture and drug resistance is essential for developing effective strategies to mitigate their clinical and environmental impact. Full article

Background/Objectives: This study examines how seasonality, pollution, and sample type (water and sediment) influence the presence and distribution of antibiotic resistance genes (ARGs), with a focus on antibiotic resistance genes (ARGs) located on plasmids (the complete set of plasmid-derived sequences, including ARGs) in a tropical urban river. Methods: Samples were collected from three sites along a pollution gradient in the Virilla River, Costa Rica, during three seasonal campaigns (wet 2021, dry 2022, and wet 2022). ARGs in water and sediment were quantified by qPCR, and metagenomic sequencing was applied to analyze chromosomal and plasmid-associated resistance profiles in sediments. Tobit and linear regression models, along with multivariate ordination, were used to assess spatial and seasonal trends. Results: During the wet season of 2021, the abundance of antibiotic resistance genes (ARGs) such as sul-1, intI-1, and tetA in water samples decreased significantly, likely due to dilution, while intI-1 and tetQ increased in sediments, suggesting particle-bound accumulation. In the wet season 2022, intI-1 remained low in water, qnrS increased, and sediments showed significant increases in tetQ, tetA, and qnrS, along with decreases in sul-1 and sul-2. Metagenomic analysis revealed spatial differences in plasmid-associated ARGs, with the highest abundance at the most polluted site (Site 3). Bacterial taxa also showed spatial differences, with greater plasmidome diversity and a higher representation of potential pathogens in the most contaminated site. Conclusions: Seasonality and pollution gradients jointly shape ARG dynamics in this tropical river. Plasmid-mediated resistance responds rapidly to environmental change and is enriched at polluted sites, while sediments serve as long-term reservoirs. These findings support the use of plasmid-based monitoring for antimicrobial resistance surveillance in aquatic systems. Full article

Effective management of fecal pollutants in rural sanitation is crucial for environmental health and public safety, especially in developing regions. In this study, temporal and regional variations in nutrient elements, heavy metals, pathogenic microorganisms (PMs), and antibiotic resistance genes (ARGs) of fecal samples from rural toilets in China were investigated. The moisture contents of the fecal samples average 92.7%, decreasing seasonally from 97.4% in summer to 90.6% in winter. The samples’ pH values range from 6.5 to 7.5, with a slight decrease in winter (6.8), while their electrical conductivity varies from 128.1 to 2150 μs/cm, influenced by regional diets. Chromium (9.0–49.7 mg/kg) and copper (31.9–784.4 mg/kg) levels vary regionally, with higher concentrations in Anhui and Guangxi Provinces due to dietary and industrial factors. Zinc contents range from 108.5 to 1648.9 mg/kg, with higher levels in autumn and winter, resulting from agricultural practices and Zn-containing fungicides, posing potential health and phytotoxicity risks. Seasonal and regional variations in PMs and ARGs were observed. Guangxi Province shows the high PM diversity in summer samples, while Jiangsu Province exhibits the high ARGs types in autumn samples. These findings highlight the need for improved waste management and sanitation solutions in rural areas to mitigate environmental risks and protect public health. Continued research in these regions is essential to inform effective sanitation strategies. Full article

The perianal skin is a unique “skin–gut” boundary that serves as a critical hotspot for the exchange and evolution of antibiotic resistance genes (ARGs). However, its role in the dissemination of antimicrobial resistance (AMR) has often been underestimated. To characterize the resistance patterns in the perianal skin environment of patients with perianal diseases and to investigate the drivers of AMR in this niche, a total of 51 bacterial isolates were selected from a historical strain bank containing isolates originally collected from patients with perianal diseases. All the isolates originated from the skin site and were subjected to antimicrobial susceptibility testing, whole-genome sequencing, and co-occurrence network analysis. The analysis revealed a highly structured resistance pattern, dominated by two distinct modules: one representing a classic Staphylococcal resistance platform centered around mecA and the bla operon, and a broad-spectrum multidrug resistance module in Gram-negative bacteria centered around tet(A) and predominantly carried by IncFIB and other IncF family plasmids. Further analysis pinpointed IncFIB-type plasmids as potent vehicles driving the efficient dissemination of the latter resistance module. Moreover, numerous unexplained resistance phenotypes were observed in a subset of isolates, indicating the potential presence of emerging and uncharacterized AMR threats. These findings establish the perianal skin as a complex reservoir of multidrug resistance genes and a hub for mobile genetic element exchange, highlighting the necessity of enhanced surveillance and targeted interventions in this clinically important ecological niche. Full article

Background/Objectives: This study evaluated the in vitro probiotic potential of Lactiplantibacillus plantarum Probio87 (Probio87), focusing on its physiological robustness, safety, antimicrobial properties, and anticancer activity, with relevance to vaginal and cervical health. Methods: Tests included acid and bile salt tolerance, mucin adhesion, and carbohydrate utilization. Prebiotic preferences were assessed using FOS, GOS, and inulin. Antibiotic susceptibility was evaluated per EFSA standards. Antimicrobial activity of the cell-free supernatant (CFS) was tested against Staphylococcus aureus, Escherichia coli, and Candida species. Effects on Lactobacillus iners and L. crispatus were analyzed. Anticancer properties were assessed in HeLa, CaSki (HPV-positive), and C-33A (HPV-negative) cervical cancer cell lines through proliferation, apoptosis, angiogenesis, and cell cycle assays. Results: Probio87 showed strong acid and bile tolerance, efficient mucin adhesion, and broad carbohydrate utilization, favoring short-chain prebiotics like FOS and GOS over inulin. It met EFSA antibiotic safety standards. The CFS exhibited potent antimicrobial activity, including complete inhibition of Candida albicans. Probio87 selectively inhibited L. iners without affecting L. crispatus, indicating positive modulation of vaginal microbiota. In cervical cancer cells, the CFS significantly reduced proliferation and angiogenesis markers (p < 0.05), and induced apoptosis and cell cycle arrest in HPV-positive cells, with minimal effects on HPV-negative C-33A cells. Conclusions: Probio87 demonstrates strong probiotic potential, with safe, selective antimicrobial and anticancer effects. Its ability to modulate key microbial and cancer-related pathways supports its application in functional foods or therapeutic strategies for vaginal and cervical health. Full article

Background/Objectives: Actinobacteria are one of the largest bacterial phyla. These microbes produce bioactive compounds, such as antifungals, antibiotics, immunological modulators, and anti-tumor agents. Studies on actinobacteria isolated from the Brazilian Savannah biome (Cerrado) are scarce and mostly address metagenomics or the search for hydrolytic enzyme-producing microbes. Solanum lycocarpum (lobeira) is a tree widely employed in regional gastronomy and pharmacopeia in Central Brazil. Methods: In this work, 60 actinobacteria isolates were purified from the rhizosphere of S. lycocarpum. Eight Streptomyces spp. isolates were selected for in vitro antifungal activity against Cryptococcus neoformans H99, the C. neoformans 89-610 fluconazole-tolerant strain, C. gattii NIH198, Candida albicans, C. glabrata, and C. parapsilosis. The ability of the aqueous extracts of the isolates to induce the in vitro secretion of tumor necrosis factor (TNF-α), nitric oxide (NO), interleukin-6 (IL-6), and IL-10 by murine macrophages was also evaluated. Results: All extracts showed antifungal activity against at least two yeast species. Streptomyces spp. LAP11, LDB2, and LDB17 inhibited C. neoformans growth by 40–93%. Most extracts (except LAP2) also inhibited C. gattii. None inhibited C. albicans, but all inhibited C. glabrata (40–90%). Streptomyces sp. LAP8 extract increased nitric oxide production by approximately 347-fold in murine macrophages, while LDB11 extract suppressed LPS-induced TNF-α production by 70% and simultaneously increased IL-10 secretion, suggesting immunosuppressive potential. Conclusions: The results revealed that Cerrado actinobacteria-derived aqueous extracts are potential sources of antifungal and immunomodulatory biocompounds. Full article

Measuring antimicrobial use (AMU) in animal production can provide useful data for monitoring AMU over time, which will promote antimicrobial resistance (AMR) reduction. This study involved the daily collation and validation of active primary drug sales and prescription data from veterinary outlets and clinics of the Kaduna metropolis. In total, 83.7% of the identified antimicrobials were in the form of oral medication, and most were registered antibiotics (52.8%). Parenteral and topical forms were also identified, with 94% also being antibiotics. The estimated AMU was 282 mg/kg population correction unit (PCU). Poultry represented the most significant population, constituting 99% (31,502,004) of the study population. The class-specific AMU was antibiotics, with 274 mg/kg PCU. The antiprotozoal AMU was 418 mg/kg PCU. The anthelminthic AMU was the highest at 576 mg/kg PCU. This study has provided useful and practical information on the trends in antimicrobial use in animals, with poultry being the most important animal population involved in AMU and oxytetracycline being the most abused antibiotic in animal production. Antimicrobial stewardship (AMS) should be targeted at poultry populations, with an emphasis on reducing antibiotic use/consumption. Full article

Background/Objectives: Strengthening antimicrobial stewardship (AMS) programs is an invaluable intervention in the ongoing efforts to contain the threat of antimicrobial resistance (AMR), particularly in low-resource settings. This study evaluates the impact of the Telementoring, Education, and Advocacy Collaboration initiative for Health through Antimicrobial Stewardship (TEACH AMS), which uses the virtual Extension for Community Healthcare Outcomes (ECHO) learning model to enhance AMS capacity in Kenya, Ghana, and Malawi. Methods: A mixed-methods approach was used, which included attendance data collection, facility-level assessments, post-session and follow-up surveys, as well as focus group discussions. Results: Between September 2023 and February 2025, 77 virtual learning sessions were conducted, engaging 2445 unique participants from hospital-based AMS committees and health professionals across the three countries. Participants reported significant knowledge gain, and data showed facility improvements in two core AMS areas, including the implementation of multidisciplinary ward-based interventions/communications and enhanced monitoring of antibiotic resistance patterns. Along those lines, participants reported that the program assisted them in improving prescribing and culture-based treatments, and also evidence-informed antibiotic selection. The evidence of implementing ward-based interventions was further stressed in focus group discussions, as well as other strengthened practices like point-prevalence surveys, and development or revision of stewardship policies. Substantial improvements in microbiology services were also shared by participants, particularly in Malawi. Other practices mentioned were strengthened multidisciplinary communication, infection prevention efforts, and education of patients and the community. Conclusion: Our findings suggest that a virtual case-based learning educational intervention, providing structured and tailored AMS capacity building, can drive behavior change and strengthen healthcare systems in low resource settings. Future efforts should aim to scale up the engagements and sustain improvements to further strengthen AMS capacity. Full article

Schaalia canis is a Gram-positive, facultatively anaerobic, rod-shaped bacterium originally isolated from the mucosa and skin of dogs. While it is a part of the normal canine oral flora, it has rarely been implicated in human disease, with only one prior case of cellulitis reported following a dog bite. Case Presentation: We present the case of a 57-year-old immunocompetent man who developed osteomyelitis of the left index finger following a delayed presentation after a dog bite. Despite initial conservative management with empirical oral antibiotics, the infection progressed, eventually requiring surgical debridement and the terminalisation of the finger at the proximal interphalangeal joint. Cultures from intraoperative bone specimens yielded the growth of Schaalia canis, with no other pathogenic organisms identified on the extended culture. Conclusions: This is the first documented case of Schaalia canis-associated osteomyelitis in a human and the first to necessitate a surgical intervention, expanding the known clinical spectrum of this organism. This case underscores the risks of delayed intervention in polymicrobial animal bite wounds and highlights the emerging role of Schaalia species as opportunistic zoonotic pathogens, particularly in the setting of deep, refractory infections. Full article

Background/Objectives: Enterococci, particularly Enterococcus faecalis and Enterococcus faecium, are Gram-positive cocci that can cause severe infections in hospitalized patients. The rise of vancomycin-resistant enterococci (VRE) and vancomycin-variable enterococci (VVE) poses significant challenges in healthcare settings due to their resistance to multiple antibiotics. Methods: We conducted a point prevalence survey (PPS) to assess the prevalence of VRE and VVE colonization in hospitalized patients. Rectal swabs were collected from 160 patients and analyzed using molecular assays (MAs) and culture. Whole-genome sequencing (WGS) and core-genome multilocus sequence typing (cgMLST) were performed to identify the genetic diversity. Results: Of the 160 rectal swabs collected, 54 (33.7%) tested positive for the vanA and/or vanB genes. Culture-based methods identified 47 positive samples (29.3%); of these, 44 isolates were identified as E. faecium and 3 as E. faecalis. Based on the resistance profiles, 35 isolates (74.5%) were classified as VRE, while 12 (25.5%) were classified as VVE. WGS and cgMLST analyses identified seven clusters of E. faecium, with sequence type (ST) 80 being the most prevalent. Various resistance genes and virulence factors were identified, and this study also highlighted intra- and inter-ward transmission of VRE strains. Conclusions: Our findings underscore the potential for virulence and resistance of both the VRE and VVE strains, and they highlight the importance of effective infection control measures to prevent their spread. VVE in particular should be carefully monitored as they often escape detection. Integrating molecular data with clinical information will hopefully enhance our ability to predict and prevent future VRE infections. Full article

Phage therapy, long overshadowed by antibiotics in Western medicine, has a well-established history in some Eastern European countries and is now being revitalized as a promising strategy against antimicrobial resistance (AMR). This resurgence of phage therapy is driven by the urgent need for innovative countermeasures to AMR, which will cause an estimated 10 million deaths annually by 2050. However, the emergence of phage-resistant variants presents challenges similar to AMR, thus necessitating a deeper understanding of phage resistance mechanisms and control strategies. The highest priority must be to prevent the emergence of phage resistance. Although phage cocktails targeting multiple receptors have demonstrated a certain level of phage resistance suppression, they cannot completely suppress resistance in clinical settings. This highlights the need for strategies beyond simple resistance suppression. Notably, recent studies examining fitness trade-offs associated with phage resistance have opened new avenues in phage therapy that offer the potential of restoring antibiotic susceptibility and attenuating pathogen virulence despite phage resistance. Thus, controlling phage resistance may rely on both its suppression and strategic redirection. This review summarizes key concepts in the control of phage resistance and explores evolutionary engineering as a means of optimizing phage therapy, with a particular focus on Pseudomonas infections. Harnessing evolutionary dynamics by intentionally breaking the spontaneous evolutionary trajectories of target bacterial pathogens could potentially reshape bacterial adaptation by acquisition of phage resistance, unlocking potential in the application of phage therapy. Full article

Background: The aim of this review is to summarize and evaluate the properties of antibacterial polysaccharides for application in dental implantology to identify knowledge gaps and provide new research ideas. Methods: The electronic databases PubMed, Medline, ProQuest, and Google Scholar were used to search for peer-reviewed scientific publications published between 2018 and 2025 that provide insights to answer research questions on the role of antibacterial polysaccharides in combating pathogens in dental implantology without triggering immune reactions and inflammation. Further research questions relate to the efficacy against various dental pathogens and the understanding of the antibacterial mechanism, which may enable the development of functionalized polysaccharides with long-term antibacterial activity. Results: Biomedical implants have revolutionized medicine but also increased the risk of infections. Implant infections are a major problem in implantology and lead to implant failure and replacement. An antibacterial coating could be an excellent strategy to extend the lifespan of implants and improve the quality of the patient’s life. Bacterial resistance to antibiotics poses significant challenges for researchers, forcing them to search for new ways to prevent bacterial infections in implantology. Antibacterial natural polymers have recently received considerable research attention due to their long-term antibacterial activity. Polysaccharides from marine sources, such as chitosan and alginate, or pectin, xanthan, etc., from various plants, appear to be promising biopolymers for such applications in implantology due to their antibacterial activity, biocompatibility, and osteogenic properties. The antibacterial activity of these natural biopolymers depends on their chemical and physical properties. Nanopolysaccharides exhibit higher antibacterial activity than conventional polysaccharides, but their toxicity to human cells must be considered. Their antibacterial activity is based on the disruption of bacterial DNA or RNA synthesis, increased cell wall permeability, membrane disruption, and cytoplasmic leakage. Conclusions: Polysaccharides are a class of natural polymers with a broad spectrum of biological activities. They exhibit antioxidant, immunomodulatory, anticoagulant, anticancer, anti-inflammatory, antibacterial, and antiviral activity. Furthermore, polysaccharides are non-cytotoxic and exhibit good biocompatibility with osteogenic cells. Bactericidal polysaccharides are attractive new antibacterial materials against implant infections and open up new perspectives in implantology. Full article

Heavy metal pollution represents a pervasive environmental challenge that significantly exacerbates the ever-increasing crisis of antimicrobial resistance and the capacity of microorganisms to endure and proliferate despite antibiotic interventions. This review examines the intricate relationship between heavy metals and AMR, with an emphasis on the underlying molecular mechanisms and ecological ramifications. Common environmental metals, including arsenic, mercury, cadmium, and lead, exert substantial selective pressures on microbial communities. These induce oxidative stress and DNA damage, potentially leading to mutations that enhance antibiotic resistance. Key microbial responses include the overexpression of efflux pumps that expel both metals and antibiotics, production of detoxifying enzymes, and formation of protective biofilms, all of which contribute to the emergence of multidrug-resistant strains. In the soil environment, particularly the rhizosphere, heavy metals disrupt plant–microbe interactions by inhibiting beneficial organisms, such as rhizobacteria, mycorrhizal fungi, and actinomycetes, thereby impairing nutrient cycling and plant health. Nonetheless, certain microbial consortia can tolerate and detoxify heavy metals through sequestration and biotransformation, rendering them valuable for bioremediation. Advances in biotechnology, including gene editing and the development of engineered metal-resistant microbes, offer promising solutions for mitigating the spread of metal-driven AMR and restoring ecological balance. By understanding the interplay between metal pollution and microbial resistance, we can more effectively devise strategies for environmental protection and public health. Full article

Background/Objective: The COVID-19 pandemic profoundly transformed social life worldwide, indiscriminately affecting individuals across all age groups. Children have not been exempted from the risk of severe illness and death caused by COVID-19. Objective: This paper sought to describe the clinical findings, laboratory and imaging results, and hospital care provided for severe and critical cases of COVID-19 in unvaccinated children, with or without severe asthma, hospitalized in a public referral service for COVID-19 treatment in the Brazilian state of Pernambuco. Methods: This was a case series study of severe and critical COVID-19 in hospitalized, unvaccinated children, with or without severe asthma, conducted in a public referral hospital between March 2020 and June 2021. Results: The case series included 80 children, aged from 1 month to 11 years, with the highest frequency among those under 2 years old (58.8%) and a predominance of males (65%). Respiratory diseases, including severe asthma, were present in 73.8% of the cases. Pediatric multisystem inflammatory syndrome occurred in 15% of the children, some of whom presented with cardiac involvement. Oxygen therapy was required in 65% of the cases, mechanical ventilation in 15%, and 33.7% of the children required intensive care in a pediatric intensive care unit. Pulmonary infiltrates and ground-glass opacities were common findings on chest X-rays and CT scans; inflammatory markers were elevated, and the most commonly used medications were antibiotics, bronchodilators, and corticosteroids. Conclusions: This case series has identified key characteristics of children with severe and critical COVID-19 during a period when vaccines were not yet available in Brazil for the study age group. However, the persistence of low vaccination coverage, largely due to parental vaccine hesitancy, continues to leave children vulnerable to potentially severe illness from COVID-19. These findings may inform the development of public health emergency contingency plans, as well as clinical protocols and care pathways, which can guide decision-making in pediatric care and ensure appropriate clinical management, ultimately improving the quality of care provided. Full article

This study was undertaken to identify foodborne bacteria and fungi from different parts of eggs depending on their storage duration, organoleptic properties, total viable count, and antibiotic resistance profile. Thirty-two samples were randomly collected from commercial layer farms in Mymensingh. Following the protocol of sample preparation, outer-surface and inner-content samples were streaked onto various selective media. Isolation and identification were carried out by observing Gram staining and biochemical properties. Molecular detection was confirmed through a PCR assay using specific primers for Salmonella spp., E. coli, Staphylococcus spp., and fungus (Simplicillium spp. and Saccharomyces spp.). To determine the antibiotic resistance profile, the disk diffusion method was followed against nine antibiotic disks. The isolation rate of E. coli, Salmonella spp., and Staphylococcus spp. was 53.13%, 40.63%, and 40.63%, respectively, in the outer eggshell and 15.63%, 25%, and 15.63%, respectively, in the inner content of the eggs. Regarding the fungus content (yeast and mold), 100% was obtained in the outer eggshell, whereas there was an absence of fungus in the inner content. It was observed that all the isolates of E. coli, Salmonella spp., and Staphylococcus spp. were highly sensitive to either Ciprofloxacin or Levofloxacin and extremely resistant to Amoxicillin or Azithromycin drug disks or both. The data also shows that storage duration had a proportional relationship with TVC and an inversely proportional relationship with organoleptic properties. This study indicates that eggs harbor multidrug-resistant foodborne bacteria, which might constitute a public health hazard if these antibiotic-resistant bacteria are transferred to humans. Full article