Search Results (10,045)

Silver nanoparticles (AgNPs) possess distinct physicochemical characteristics and demonstrate high antibacterial potential that highlights them as promising alternatives against a wide range of pathogens. The immense antibacterial potential of AgNPs is primarily attributed to the release of silver ions that lead to the disruption of bacterial cell membrane, generation of reactive oxygen species (ROS), inhibition of protein synthesis and interference with DNA replication. Variations in AgNPs’ shape, size, and surface characteristics are also considered key factors determining their effectivity as well as specificity. AgNPs are considered potent antibacterial agents, including against antibiotic- and drug-resistant strains. However, inappropriate dosages or unoptimized application of may result in potential toxicity, consisting one of the main drawbacks of the AgNPs’ safer administration. This article reviews the recent literature on the antibacterial potential of AgNPs, focusing on their broad mechanisms of action, applicability, especially in agriculture, biomedical and environmental fields, toxicity and future perspectives. Full article

Salmonella, a major global foodborne pathogen, is a leading cause of salmonellosis. Quantitative detection of Salmonella provides a scientific basis for establishing microbiological criteria and conducting risk assessments. The plate count method remains the primary approach for bacterial quantification, whereas the most probable number (MPN) method is commonly used for detecting low levels of bacterial contamination. However, both methods are time-consuming and labor-intensive. Validated digital polymerase chain reaction (dPCR) techniques are emerging as promising alternatives because they enable rapid, absolute quantification with high specificity and sensitivity. Herein, we developed a novel droplet dPCR (ddPCR) assay for identifying and quantifying Salmonella using invA as the target. The assay demonstrated high specificity and sensitivity, with a limit of quantification of 1.1 × 10² colony-forming units/mL in meat samples. Furthermore, the log₁₀ values obtained via ddPCR and plate counting exhibited a strong linear relationship (R² > 0.99). Mathematical modeling of growth kinetics further confirmed a high correlation between plate count and ddPCR measurements (Pearson correlation coefficient: 0.996; calculated bias factor: 0.88). Collectively, these results indicate that ddPCR is a viable alternative to the MPN method and represents a powerful tool for the quantitative risk assessment of food safety. Full article

The intensification of aquaculture practices has been accompanied by an increased incidence of bacterial diseases, leading to a greater reliance on antibiotics for disease control. Consequently, the widespread and often indiscriminate use of these compounds has contributed to the emergence and dissemination of antibiotic-resistant bacteria within aquaculture systems, posing a serious threat to animal health, environmental sustainability, and public health. In this regard, research efforts have focused on developing alternative strategies to reduce antibiotic use. Natural compounds have gained particular attention due to their well-documented antimicrobial and antibiofilm activities. In this context, the combined application of antibiotics and natural compounds has emerged as a promising approach to enhance antimicrobial efficacy while potentially mitigating the development of resistance. This review synthesizes the current knowledge on antibiotic resistance in aquaculture, highlights the role of biofilm formation as a key resistance mechanism, and critically examines the potential of antibiotic–natural compound combinations against major aquaculture pathogens, with particular emphasis on bacterial growth inhibition, biofilm disruption, and virulence attenuation. Collectively, the evidence discussed underscores the potential of synergistic strategies as a sustainable tool for improving disease management in aquaculture while supporting efforts to limit antibiotic resistance. Full article

Background: Libya, a conflict-affected North African country, has a fragile health system and poor surveillance, leaving it largely underrepresented in global estimates. Earlier Libyan reviews were descriptive, lacking breakpoint standardization, isolate-level pooling, or AMR-attributable mortality and DALY estimates. To our knowledge, this study represents the first comprehensive report that integrates phenotypic and genotypic data to estimate deaths and DALYs attributable to AMR-induced mortality and morbidity, describe spatiotemporal patterns, and model future trajectories. Methods: We performed a meta-analysis according to the PRISMA 2020 guideline of Libyan studies reporting phenotypic or genotypic resistance among clinical bacterial isolates (1970–2024), combined with microbiology records from hospitals and national surveillance systems (preregistered in PROSPERO ID: CRD420251066018). Susceptibility results were standardized to CLSI/EUCAST and deduplicated using WHO GLASS first-isolate rules. We used random-effects meta-regression to estimate pooled resistance, and the counterfactual approach of Global Burden of Disease (GBD) was applied to estimate AMR-attributable DALYs. Molecular data on resistance genes, sequence types, and tuberculosis mutations were systematically collected. Results: We included 62 eligible studies together with national and facility-level surveillance datasets, providing isolate-level susceptibility data for 31,439 clinical isolates from Libya. In 2024, we estimated 2183 deaths (95% UI 1752–2614) attributable to AMR, representing 9.7% (95% UI 7.8–11.6) of total deaths with a mortality rate of 15.2 per 100,000 (12.2–18.2). DALYs attributable to AMR increased from 14,628 (95% UI 11,702–17,554) in 1970 to 96,715 (95% UI 77,372–116,058). The highest pooled resistance involved carbapenem-resistant/MDR A. baumannii, third-generation cephalosporin- and fluoroquinolone-resistant Enterobacterales, and carbapenem-resistant P. aeruginosa. Molecular data showed widespread ESBLs, OXA-/NDM-type carbapenemases, plasmid-mediated colistin resistance, high-risk E. coli ST131 and K. pneumoniae ST147 lineages, and canonical drug-resistant M. tuberculosis mutations. Conclusions: Combined with global and regional evidence, our findings suggest a high and increasing burden of AMR in Libya. These findings emphasize the need for rapid expansion of data collection systems, GLASS-aligned surveillance, diagnostic capacities, and infection control measures. Full article

Bacteriophage (phage) therapy, including monophage preparations, phage cocktails, engineered phages, and phage-derived enzymes, has re-emerged as a potential option for difficult-to-treat and biofilm-associated infections in the context of rising antimicrobial resistance. Recent scientific and regulatory developments, such as the 2024 World Health Organization Bacterial Priority Pathogens List and the introduction of the European Pharmacopoeia general chapter 5.31 on phage therapy medicinal products, highlight the growing interest in establishing quality, safety, and governance standards for clinical implementation. This narrative review provides an overview of current clinical applications of phage therapy, drawing on published case reports, case series, early-phase clinical studies, and regulatory experiences across different healthcare settings. Clinical use has been reported in respiratory, urinary tract, musculoskeletal, cardiovascular, and device-associated infections, particularly in cases involving multidrug-resistant pathogens, often in combination with antibiotics. At the same time, the biological characteristics of phages, such as strain specificity, adaptive composition of phage cocktails, and the need for individualized formulations, pose significant regulatory and translational challenges. Access to phage therapy currently relies on heterogeneous regulatory mechanisms, including compassionate use programmes, magistral preparations, named-patient pathways, and other national frameworks. Overall, phage therapy represents a promising strategy for selected infections, but its broader clinical adoption will depend on harmonized regulatory approaches, robust quality standards, and the generation of stronger clinical evidence to support safe and scalable use. Full article

Astroviruses are non-enveloped, positive-sense single-stranded RNA viruses known to infect various mammals and birds, including humans, often causing gastrointestinal disorders. In recent years, astroviruses have also been linked to neurological and respiratory diseases across several species, including ruminants, mink, deer, and other mammals. Notably, astrovirus infections in goats have been documented in countries such as Switzerland and China, where novel genotypes have been identified in fecal samples. However, their role in the context of disease remains unclear, and reports focusing solely on goat astrovirus in the United States have not been published. A necropsy case of a Boer goat kid with a history of diarrhea was submitted for investigation following death in January 2025. Fresh tissues were received and used for histopathology and enteric pathogen testing, including parasitic, bacterial, and viral workups. Metagenomic-based next-generation sequencing (mNGS) was also applied for this case. Histological examination revealed severe necrotizing enterocolitis. The small intestine exhibited epithelial ulcerations, villus atrophy, hyperplastic and dilated crypts with necrotic debris, few intraenterocytic coccidian parasites, and increased inflammatory cells in the lamina propria. The large intestine showed similar findings with pleomorphic crypt enterocytes. Standard enteric pathogen tests were negative except for aerobic culture that identified Escherichia.coli and Enterococcus hirae. mNGS and bioinformatic analysis identified a novel astrovirus in the intestinal content that showed the highest nucleotide identity (86%) to the sheep strain Mamastrovirus 13 sheep/HA3 from China based on BLAST analysis. Phylogenetic analysis indicated that the newly identified caprine astrovirus IL90175 clustered with astrovirus strains from small ruminants in Asia and Europe. This research reports the discovery, histopathologic features, and genetic characteristics of a gastrointestinal disease-causing astrovirus in a goat kid, which had not been previously described in the United States. Full article

Antibiotic feeding in shrimp farming is an optional practice conducted with the aim of preventing and controlling bacterial diseases. However, the administration of antibiotics can disrupt the microbiota of both shrimp and surrounding environment, potentially compromising host health. Given the limited effective antibiotic options in aquaculture, it is crucial to evaluate the effects of florfenicol (FF) on the intestinal health of shrimp and the associated microbial communities. This study first investigated the impact of FF on the intestinal structure of Penaeus vannamei over two feeding durations (5 and 10 days), each followed by a 10-day basal diet recovery period. Simultaneously, variations in microbial communities and antibiotic resistance genes (ARGs) in both the intestine and rearing water were explored. The results showed that intestinal damage was aggravated with the extension of FF duration and gradually recovered after FF withdrawal. Significant changes in microbial composition and β-diversity were observed in both the rearing water and intestine following FF feeding. Extending the FF treatment to 10 days led to a reduced abundance of Rhodobacteraceae and an increased abundance of Flavobacteriaceae and Vibrionaceae in the intestine after 10 days of feeding the basic diet, which may pose a potential risk to shrimp health. Based on correlation analysis of ARGs, microbial communities and pathogenic bacteria, we speculated that rearing water may serve as a reservoir for ARGs dissemination compared to the shrimp intestine. These findings are of great importance for assessing the impact of administration duration under the FF therapeutic dose and highlight the potential risks associated with its overuse in shrimp farming. Full article

Zinc (Zn), a ubiquitous environmental transition metal primarily existing as Zinc ions (Zn²⁺), plays a critical role in various biological processes. Its extensive application in agriculture, industry, and healthcare has led to significant environmental contamination. However, the mechanistic contribution of Zn²⁺ to bacterial antibiotic resistance and virulence remains insufficiently understood. This review explores the sources, cycling, and environmental accumulation of Zn²⁺ in a One Health context, emphasizing their impact on bacterial antibiotic resistance and virulence. Zn²⁺ promote bacterial antibiotic resistance by regulating efflux pumps, biofilm formation, expression and transfer of antibiotic resistance genes, as well as synergistic effects with other heavy metals and antibiotics. Meanwhile, Zn²⁺ promote bacterial virulence by regulating quorum sensing, secretion and metal homeostasis systems, as well as oxidative stress response and virulence factor expression. Additionally, it highlights the potential of targeting Zn homeostasis as a strategy to combat environmental antibiotic resistance. Collectively, these findings provide key insights into the mechanisms by which Zn²⁺ regulate bacterial antibiotic resistance and pathogenicity, offering valuable guidance for developing strategies to mitigate the global threat of antibiotic resistance. Full article

Staphylococcus aureus is a major opportunistic pathogen responsible for a wide spectrum of human infections, including severe and difficult-to-treat cases. The emergence of multidrug-resistant strains limits the efficacy of conventional antibiotic therapies and poses a significant global public health challenge. In this context, the search for novel antibiotics has intensified, with increasing interest in marine resources, an ecosystem still largely underexplored. Marine bacteria produce a vast array of secondary metabolites with unique structures and potentially novel modes of antibacterial action. Several compounds isolated from marine bacterial strains have demonstrated promising activity against multidrug-resistant S. aureus, including antivirulence effects such as biofilm formation and Quorum-Sensing inhibition. This review explores the potential of marine bacteria as a source of new antibiotics against S. aureus, discusses both classical and advanced strategies for the discovery of bioactive molecules, and highlights the scientific and technological challenges involved in translating these findings into clinical applications. Full article

Streptococcus uberis is a bovine mastitis pathogen with a demonstrated ability to form biofilms. However, the dynamics of this process remain poorly characterized. This study aimed to comprehensively characterize biofilm formation in four S. uberis strains that differed in their biofilm-forming capacity, from weak to strong producers, and in the presence of key virulence-associated genes, such as sua, hasA and hasC. To achieve this, we integrated structural, biochemical, physiological and transcriptional analyses using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), spectral flow cytometry and qRT-PCR. The multi-faceted analysis revealed a coordinated maturation peak at 48 h, characterized by a structured architecture with water channels, a distinct biochemical signature rich in polysaccharides and proteins, and a predominantly viable bacterial population. This peak coincided with a marked upregulation of key virulence-associated genes, with sua expression increasing 2.5-fold and hasA increasing 3-fold at 48 h. This mature biofilm conferred high tolerance to antibiotics, with eradication concentrations (>256 µg/mL) exceeding planktonic MICs, although tetracycline was notably effective. At 72 h, the biofilm entered a dispersion phase characterized by structural collapse and reduced viability. These findings establish S. uberis biofilm maturation as a highly coordinated process, providing new insights into the biofilm lifecycle of this important pathogen and identifying key temporal and molecular targets for future interventions. Full article

Background: Salmonella is a major zoonotic foodborne pathogen. Conventional poultry vaccines may present limitations in terms of efficacy, safety, and practicality. Objectives: This study focuses on enhancing the immunogenicity and improving the safety of a novel oral vaccination employing inducible toxin–antitoxin (TA) systems, which lead to self-destruction of virulent Salmonella Enteritidis. Methods: A Hok/Sok (HS) TA system was designed to induce cell death upon absence of arabinose. Point mutations were introduced to the Hok toxin promoter to moderate toxin production. A combination of HS and CeaB/CeiB (CC) TA systems was designed to induce cell death both in low di-cation levels or anaerobic conditions. Survival of Salmonella-carrying TA systems was tested in culture and in the Raw264.7 macrophage cell line. One-day old chicks were inoculated with Salmonella carrying the TA system to evaluate bacterial persistence and induction of a protective immune response. Results: Attenuation of the Hok toxin promoter prolonged bacterial survival in vitro. Salmonella carrying the combined TA systems was eliminated completely both in vitro and in inoculated chickens, eliciting high levels of antibodies and conferring protection against challenge with wild-type Salmonella. Conclusions: These findings highlight the potential of the adaptable TA-based vaccination platform to generate safe and efficacious Salmonella vaccines for poultry, contributing to reduced transmission in the food chain. Full article

Designing robust drinking water treatment schemes for eutrophic sources requires shifting from considering each treatment step separately to considering the full treatment process as a connected system. This study evaluated how treatment configuration and arrangement influence microbial community dynamics, organic carbon removal, and biological stability in a full-scale drinking water treatment plant. A Dutch treatment plant was monitored, operating two parallel lines: one conventional (coagulation, sedimentation, and rapid sand filtration) and one advanced (ion exchange, ceramic microfiltration, and advanced oxidation), both converging into granular activated carbon (GAC) filtration. Microbial and chemical water quality was assessed across treatment stages and seasons. This plant experiences periods of discoloration, taste, and odor issues, and an exceedance of Aeromonas counts in the distribution network. Advanced oxidation achieved a high bacterial cell inactivation (~90%); however, it significantly increased assimilable organic carbon (AOC) (300–900% increase), challenging biological stability. GAC filtration partially reduced AOC levels (from 70 μg Ac-C/L to 12 μg Ac-C/L) but also supported dense (10⁵ cells/mL) and diverse microbial communities (Shannon diversity index 5.83). Moreover, Gammaproteobacteria, which harbor opportunistic pathogens such as Aeromonas, persisted during the treatment. Archaea were highly sensitive to oxidative and physical stress, leading to reduced diversity downstream. Beta diversity analysis revealed that treatment configuration, rather than seasonality, governed the community composition. The findings highlight that treatment arrangement, oxidation, GAC operation, and organic and microbial loads critically influence biological stability. This study proposes integrated strategies to achieve resilient and biologically stable drinking water production when utilizing complex water sources such as eutrophic lakes. Full article

Bacterial and viral diseases significantly reduce soybean (Glycine max) yield and quality. RNA modifications, particularly N⁶-methyladenosine (m⁶A), are increasingly recognized as having a regulatory role in plant–pathogen interactions, but the m⁶A methylome of soybean during viral and bacterial infection has not yet been characterized. Here, we performed transcriptome sequencing and MeRIP-seq (methylated RNA immunoprecipitation followed by high-throughput sequencing) of soybean leaves infected with Soybean mosaic virus (SMV) and/or Pseudomonas syringae pv. glycinea (Psg). In general, m⁶A peaks were highly enriched near stop codons and in 3′-UTR regions of soybean transcripts, and m⁶A methylation was negatively correlated with transcript abundance. Multiple genes showed differential methylation between infected and control plants: 1122 in Psg-infected plants, 539 in SMV-infected plants, and 2269 in co-infected plants; 195 (Psg), 84 (SMV), and 354 (Psg + SMV) of these transcripts were both differentially methylated and differentially expressed. Interestingly, viral infection was predominantly associated with hypermethylation and downregulation, whereas bacterial infection was predominantly associated with hypomethylation and upregulation. GO and KEGG enrichment analysis revealed shared processes likely affected by changes in m⁶A methylation during bacterial and viral infection, including ATP-dependent RNA helicase activity, RNA binding, and endonuclease activity, as well as specific processes affected by only one pathogen. Our findings shed light on the role of m⁶A modifications during pathogen infection and highlight potential targets for epigenetic editing to increase the broad-spectrum disease resistance of soybean. Full article

Background/Objectives: The increasing trend of foodborne zoonotic pathogens exhibiting antimicrobial resistance (AMR) represents a growing threat to food safety and public health in sub-Saharan Africa (SSA). Resistant strains of foodborne zoonotic pathogens compromise treatment efficacy, raise illness, and threaten sustainable food systems in human and animal health. However, regional understanding and policy response are limited due to the fragmentation of data and the inadequacy of surveillance. This systematic review and meta-analysis aimed to achieve the following: (1) estimate the pooled prevalence of AMR, including multidrug resistance (MDR) in selected foodborne pathogens; (2) compare subgroup variations across countries, pathogen species, and antibiotic classes; and (3) evaluate temporal trends. Methods: Following PRISMA 2020 guidelines, studies published between 2010 and June 2025 reporting AMR and MDR in Salmonella, Campylobacter, or E. coli from food or animal sources in SSA were systematically reviewed. Data on pathogen prevalence, AMR profile, and MDR were extracted. Random-effects meta-analysis using R software was implemented to estimate the pooled prevalence and the 95% confidence intervals (95% CI). Subgroup analyses were performed to explore heterogeneity across countries, antibiotic class, and bacterial species. Results: Ninety studies from 16 sub-Saharan African countries were included, encompassing 104,086 positive isolates. The pooled foodborne pathogen prevalence was 53.1% (95% CI: 51.5–54.7), AMR prevalence was 61.6% (95% CI: 59.4–63.9), and MDR prevalence was 9.1% (95% CI: 8.3–10.0). The highest resistance was reported in Campylobacter spp. (43.6%), followed by Salmonella spp. (29.1%) and E. coli (22.8%). High heterogeneity was observed across studies (I² = 95–99%, p < 0.001). Conclusions: It is concluded that substantial AMR burden exists in food systems, highlighting an urgent need for integrated One Health surveillance, antimicrobial stewardship, and policy harmonization in SSA. Strengthening laboratory capacity, enforcing prudent antimicrobial use, and promoting regional data sharing are critical for the management of antimicrobial resistance in sub-Saharan Africa. Full article

Recycled wastewater is vital for the circular economy, especially on water-scarce islands. This study explored the presence of Carbapenem-Resistant Enterobacterales and other emerging pathogens in irrigation water on four Canarian Islands, applying a One Health perspective. Using membrane filtration and MALDI-TOF mass spectrometry, 69 bacterial isolates were identified. The findings revealed that 78% were Gram-negative bacilli like Pseudomonas aeruginosa, Acinetobacter spp., Enterobacteriaceae, etc., while 22% were Gram-positive bacteria, including Enterococcus spp. The main mechanisms of carbapenem resistance in Pseudomonas spp. and Acinetobacter spp. were oxacillinases, followed by metallo-β-lactamases (MBL). In Enterobacteriaceae, characterization of carbapenemase types was less frequent, with oxacillinase 48 (OXA-48) being the most prevalent. The detection of multidrug-resistant organisms in recycled wastewater highlights an urgent need for routine microbiological monitoring in water management to protect both public health and agricultural sustainability. Full article