Search Results (5,715)

Multidrug-resistant Salmonella Paratyphi poses a severe threat to public health. As conventional antibiotics lose efficacy against emerging resistant strains, the need to develop alternative antimicrobial agents has become increasingly urgent. In this study, we isolated and characterized a novel lytic bacteriophage, designated SEP1, from poultry sewage using the S. Paratyphi C strain QH as the host and systematically evaluated its therapeutic potential in a murine infection model Genomic analysis confirmed that SEP1 belongs to the genus Felixounavirus, with an 85,703-bp genome devoid of lysogeny-associated or virulence genes. SEP1 exhibits robust environmental stability, maintaining infectivity at 10–50 °C and pH 4–9; it has a 30 min latent period and a burst size of 133 PFU per infected cell. In vivo, SEP1 treatment conferred 100% survival in infected mice, reduced organ bacterial loads, alleviated tissue damage, and normalized inflammatory cytokine profiles. Collectively, these results demonstrate that SEP1 is a promising candidate for phage therapy targeting S. Paratyphi C infections. Full article

Foodborne pathogens remain a major public health challenge, particularly in the context of antimicrobial resistance and persistent contamination across animal, food-processing, and retail environments. This review examines bacteriophages as precision antimicrobials for controlling major foodborne bacteria, including Salmonella, Campylobacter, Shiga toxin-producing Escherichia coli (STEC), Listeria monocytogenes, and Vibrio spp., and summarizes the biological basis of phage-mediated control: strictly lytic life cycles, receptor-specific adsorption, direct bacterial killing, biofilm disruption, and resistance-associated fitness trade-offs. It further discusses pre-harvest, post-harvest, and processing-environment applications, with emphasis on matrix-dependent efficacy, delivery strategies, commercial products, and regulatory status. While bacteriophages offer high specificity and may help preserve the native microbiome, their integration into multi-hurdle food-safety systems require careful validation because their performance is influenced by narrow host ranges, bacterial resistance, food-matrix effects, formulation constraints, and regulatory complexity and scale-up challenges. Broader implementation will require rationally designed phage-cocktails, thorough genomic safety screening, matrix-specific validation studies, scalable manufacturing processes, and continuous monitoring for post-application resistance. Overall, bacteriophages should be viewed as promising but context-dependent adjuncts to validated food-safety and One Health frameworks, rather than stand-alone solution for reducing foodborne pathogen burdens. Full article

Food systems are usually discussed in terms of nutrition, food safety, productivity, sustainability or emissions. Less attention is given to the microbial dimension of the farm-to-fork pathway and to the way food systems shape the dietary substrates, food matrices and microbial exposures that reach the gut. Soils, plants, foods, processing environments, animals and the human gut all host microbial communities that influence nutrient cycling, plant performance, food characteristics, metabolism, immune regulation and ecological resilience. This review examines how food systems may modulate gut microbiota and microbiome resilience within a One Health framework. Evidence from soil, crop and food microbiome studies suggests that local conditions and farming practices can leave detectable microbial signatures on plants and edible tissues. However, the soil–food–gut continuum should not be understood as a simple transfer route. Microorganisms and microbial products are repeatedly filtered by plant traits, farming systems, animal-production interfaces, harvesting, processing, storage, preparation and host physiology. The review also considers how this continuity may be weakened or redirected. Agricultural intensification, pollutants, post-harvest processing, antimicrobial use, ultra-processed foods, additive mixtures, low-fibre diets, early-life microbial disruption and reduced contact with environmental biodiversity may alter microbial communities at different points of the food system. Antimicrobial resistance is also discussed as a functional microbial trait that can circulate across human, animal, food and environmental interfaces. One Health approaches to food systems should therefore combine microbial risk control with microbial stewardship: protecting useful microbial diversity and function while preserving food safety. The aim is not to maximise microbial exposure, but to understand which microbial functions matter and how food systems can support gut microbiota resilience across environments, foods and hosts. Full article

The formation of biofilms on medical devices is a major public health challenge, associated with persistent infections, increased antimicrobial resistance and device failure. Biofilms are structured microbial communities, integrated into an extracellular matrix that they produce, giving them protection against antibiotics and host immune defenses. This review provides a synthesis of the mechanisms of biofilm formation, the molecular basis of their resistance, and current and emerging strategies for their prevention and control. This narrative review summarizes (i) the bacterial composition of device-associated biofilms, (ii) the sequential mechanisms of biofilm formation (initial adhesion, maturation, dispersion), (iii) the molecular and physiological basis of biofilm-mediated antimicrobial resistance, and (iv) prevention and control strategies, with particular emphasis on antibacterial and anti-adhesive coatings for orthopedic and dental implants. Surface engineering (anti-adhesive, antimicrobial, nanostructured and biomimetic coatings), anti-biofilm agents (enzymes, quorum sensing inhibitors, bacteriophages), physical approaches (ultrasound, photodynamic therapy) and combined multimodal strategies emerge as the most promising directions. No single strategy ensures complete prevention or eradication of biofilm-associated infections; multidisciplinary multimodal approaches integrating smart biomaterials, controlled antimicrobial release, and artificial intelligence-assisted surface design represent the most realistic clinical pathway forward. Full article

Root-knot nematodes (RKNs; Meloidogyne spp.) are among the most destructive plant parasites, causing severe yield losses in diverse crops. Reactive oxygen species (ROS), particularly superoxide radicals (O₂•⁻) and hydrogen peroxide (H₂O₂), are central regulators of plant–RKN interactions. This review synthesizes current molecular, biochemical, genetic, transcriptomic, and translational evidence showing that the outcome of infection is determined by the spatiotemporal regulation of H₂O₂ rather than by ROS abundance alone. In resistant interactions, nematode perception activates PTI-associated signaling through selected cell-surface receptor complexes, including some BAK1/SERK3-associated pathways, together with BIK1, Ca²⁺ signaling, and RBOHD/F, generating a sustained oxidative activity associated with salicylic acid-dependent immune signaling and reduced H₂O₂-scavenging capacity and coupled to hypersensitive response, lignin and callose deposition, and feeding site restriction. In susceptible interactions, RKNs deploy ROS-targeting effectors such as Mi-CRT, MjTTL5, CATLe, Mj-NEROSs, and CMII to suppress ROS production, enhance antioxidant scavenging, or weaken SA-dependent defense. Evidence from a cyst-nematode system suggests that RBOH-derived ROS can restrict excessive cell death around syncytia; whether an analogous lower-redox requirement exists in RKN-induced giant cells remains unresolved. Finally, redox-based strategies, including CRISPR/Cas editing, host-induced gene silencing, chemical priming, and biocontrol, are discussed as promising approaches for durable and sustainable nematode resistance. Full article

Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA), remains a leading cause of skin and soft tissue infections (SSTIs) worldwide. Patients with renal edema, including those with nephrotic syndrome and chronic kidney disease (CKD), and critical illness, are particularly susceptible because of barrier dysfunction, immune impairment, and altered antimicrobial pharmacokinetics. This narrative review examines the mechanisms linking renal edema to increased susceptibility to cutaneous S. aureus infection and discusses their diagnostic and therapeutic implications. Three interconnected pathophysiological pathways appear central to this susceptibility: disruption of the cutaneous barrier, nephrotic and uremic immune dysfunction, and impaired lymphatic immune surveillance. These abnormalities facilitate bacterial colonization, and invasion, while S. aureus further exploits the renal host through adhesins, toxins, biofilm formation, and immune-evasion mechanisms. The review also highlights the challenges of managing severe staphylococcal infections in patients with kidney disease and critical illness, where augmented renal clearance, expanded volume of distribution, extracorporeal renal support, and fluctuating renal function may substantially influence antimicrobial exposure. Current management requires early recognition, source control, individualized antimicrobial selection, renal-adapted dosing, therapeutic drug monitoring, and antimicrobial stewardship. Although emerging anti-virulence and immunomodulatory strategies show promise, most remain at the preclinical or early translational stage. Overall, renal edema should be regarded as a biologically active modifier of host–pathogen interactions that contributes to increased susceptibility to cutaneous S. aureus infection across the spectrum of kidney disease. Full article

The Songpan-Ganzi and Eastern Kunlun region on the northern margin of the Tibetan Plateau is a key area for the evolution of the Paleo-Tethys tectonic domain and hosts abundant gold, lithium, and polymetallic mineral resources. To reveal the deep structure of this region and its metallogenic background, this study constructed a lithospheric electrical structure model based on magnetotelluric (MT) data along a profile traversing tectonic units such as the Qiangtang, Songpan-Ganzi, and Eastern Kunlun blocks. Data processing, dimensionality analysis, and two-dimensional inversion were performed. The results show that a large-scale, funnel-shaped conductor, originating from the upper mantle and penetrating the middle-lower crust, exists beneath the Songpan-Ganzi and Qiangtang terranes, indicating a major channel for deep-seated thermal material upwelling. Driven by Cenozoic tectonic reactivation, the thermal materials ascended along pre-existing lithospheric weak zones formed during the closure of the Paleo-Tethys Ocean. It spread extensively within the upper-middle crust of the Songpan-Ganzi terrane and migrated to the Eastern Kunlun orogenic belt via complex fault systems, ultimately forming low-resistivity bodies that closely coincide with the locations of major shallow ore-controlling faults. This electrical model suggests the presence of a “thermal material channel” system extending from the mantle to the shallow crust. The study suggests that the migration pathways of ore-forming fluids, represented by gold deposits in the Eastern Kunlun metallogenic belt, are highly correlated with the fault-magma channel system constituted by intra-crustal conductors. In contrast, the lithium-rich granitic magmatism associated with lithium mineralization within the Songpan-Ganzi terrane may be related to the deep thermal background reflected by the large-scale conductor in the upper mantle. From the perspective of electrical structure, this study suggests that mineralization in this region may be closely linked to deep crust–mantle processes. The reactivation of pre-existing tectonic-magmatic channels by Cenozoic thermal material is key to controlling the distribution pattern of dominant shallow mineral resources. The research results provide important geophysical constraints for a deeper understanding of the tectonic–magmatic–mineralization coupling mechanism on the northern margin of the Tibetan Plateau. Full article

Water-soluble blue microbial pigments with antioxidant activity remain rare, and their host-level protective mechanisms are poorly understood. Here, we identified the genetic basis of blue pigment biosynthesis in the glacier-derived strain Arthrobacter antioxidans QL17. Heavy-ion mutagenesis yielded a hyperpigmented mutant (M157) and a pigment-deficient mutant (M186), and pigment yield was positively associated with hydrogen peroxide (H₂O₂) tolerance. Genome mining identified MWM45_RS16760 as the sole core biosynthetic gene in a candidate nonribosomal peptide synthetase (NRPS)-like cluster. The encoded protein displayed an adenylation–peptidyl carrier protein–thioesterase (A-PCP-TE) architecture with a predicted L-glutamine-specific A domain, and its transcript abundance paralleled pigment production across the three strains. Phylogenetic analysis placed MWM45_RS16760 in a distinct actinomycete-associated indigoidine-like lineage separated from the characterized BpsA and IndC branches. Heterologous expression in Escherichia coli reconstructed a blue-pigment-producing phenotype, increased H₂O₂ tolerance, and was accompanied by enhanced extracellular DPPH and ABTS radical-scavenging activities in the culture supernatant. Comparative transcriptomics further revealed coordinated activation of oxidative-stress and proteostasis responses alongside repression of tryptophan biosynthesis and flagellar assembly. These findings identify MWM45_RS16760 as a candidate indigoidine-like NRPS associated with blue pigment biosynthesis and oxidative-stress resistance, with heterologous expression linked to enhanced radical scavenging and coordinated transcriptional reprogramming, expanding the phylogenetic and functional diversity of indigoidine-like systems. Full article

The gut microbiome of rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar) is increasingly recognized as a functional interface linking dietary inputs, epithelial barrier integrity, mucosal immunity, environmental stress, disease susceptibility, and antimicrobial-resistance risk in intensive aquaculture. Based on available salmonid studies and relevant evidence from broader fish and aquaculture systems, this review synthesizes current knowledge on salmonid gut microbial composition, nutritional modulation, microbiome–mucosal immune interactions, aquaculture stressors, antibiotic exposure, antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), metagenomics, multi-omics, and emerging microbiome-informed decision-support tools. Current evidence does not support a universally stable single-core microbiota in these species. Instead, community structure is shaped by developmental stage, freshwater–seawater transition, intestinal segment, digesta versus mucosa sampling, diet, temperature, stress, health status, and methodological workflow. Feed substitution and functional additives can remodel the gut microbiota, but these shifts should be interpreted alongside histology, barrier function, metabolic profiles, immune indicators, and disease-resistance phenotypes. Antibiotic exposure may reduce acute bacterial disease pressure while disturbing community structure and potentially enriching ARGs or ARG–MGE associations. Risk assessment should therefore move beyond ARG abundance toward host–ARG–MGE linkage using shotgun metagenomics, metagenome-assembled genomes, long-read sequencing, Hi-C, and externally validated multi-omics models. Machine learning and artificial intelligence approaches may support feature screening, risk stratification, and decision support, but their application in salmonid gut-health management remains at an early stage and requires external validation across sites, production stages, diets, and seasons. Full article

Feline obesity is an increasingly prevalent health concern and is closely associated with metabolic disorders and intestinal dysbiosis. This study aimed to screen feline-derived lactic acid bacteria (LAB) for bile salt hydrolase activity, in vitro cholesterol-removal capacity, and selected probiotic-associated characteristics. Approximately 700 LAB isolates were obtained from fecal samples of healthy domestic cats and evaluated for bile salt hydrolase (BSH) activity, among which 105 isolates were identified as BSH-positive. Further screening was performed based on BSH activity, cholesterol-removal capacity, adhesion-related properties, antioxidant activity, gastrointestinal tolerance, antibacterial activity, organic acid production, hemolytic activity, and antibiotic susceptibility. Three candidate strains were ultimately selected and preliminarily identified by 16S rRNA gene sequencing as Enterococcus hirae C283, Ligilactobacillus animalis C289, and Enterococcus faecium C422. These strains exhibited BSH activity and preliminary in vitro cholesterol-removal phenotypes under the tested culture conditions, together with tolerance to simulated gastrointestinal conditions, antioxidant activity, antibacterial activity, and organic acid production. No hemolytic activity was detected; however, all three strains exhibited resistant or intermediate phenotypes to multiple antibiotics, highlighting the need for further genome-based safety assessment, particularly for the two Enterococcus strains. Overall, these findings identified feline-derived LAB candidates with BSH activity, preliminary in vitro cholesterol-removal phenotypes, and multiple probiotic-associated characteristics. However, these in vitro findings do not demonstrate regulation of host lipid metabolism or blood lipid levels. Comprehensive safety assessment, particularly for the Enterococcus strains, and in vivo validation are required before further application. Full article

Background: Cutibacterium avidum is an emerging opportunistic pathogen responsible for device-associated infections, including prosthetic joint and breast implant infections. Unlike its relative C. acnes, for which phage therapy has been explored, C. avidum infections are recalcitrant to antibiotics, and no infecting bacteriophages have been described to date. Here, we report the isolation and characterization of ΦCA1NRNZ, to the best of our knowledge, the first lytic phage described against C. avidum. Methods: ΦCA1NRNZ was obtained from wastewater sampling at the Sorek Treatment Facility in Jerusalem. Wastewater metagenomics, transmission electron microscopy, genome sequencing, host-range testing, efficiency of plating (EOP), aerobic and anaerobic lysis assays, and antibiofilm assays against mature C. avidum biofilms were performed. Results: Metagenomic analysis indicated low and transient detection of C. avidum-classified reads in wastewater. ΦCA1NRNZ was identified as a long-tailed Caudoviricetes with a ~320 nm virion. Its 33,712 bp dsDNA genome (GenBank PV441878.1) encodes 46 predicted proteins, shares 76.5% nucleotide identity with C. acnes phage ΦFD1, and contains divergent tail-fiber and host-recognition genes. No known bacterial virulence, toxin, human pathogenicity-associated, or antibiotic-resistance genes were identified. ΦCA1NRNZ lysed all 11 clinical C. avidum isolates tested under aerobic and anaerobic conditions, with EOP values of 0.11–5.55, mean 1.87, and showed no lytic activity against 25 C. acnes isolates. Against mature biofilms, ΦCA1NRNZ reduced total biomass by 28.4% (p = 0.014), reduced viable cell counts by approximately two logs, and increased extracellular ATP release (p < 0.001). Conclusions: The strict species specificity and significant in vitro antibiofilm activity of ΦCA1NRNZ support its potential for phage therapy of device-associated C. avidum infections. Full article

Serratia marcescens is a nosocomial pathogen that has acquired resistance to multiple antibiotics, necessitating alternative antimicrobial strategies. The aim of this study was to isolate and characterize a novel phage (ØAS2) against Serratia marcescens and evaluate its biocontrol potential in dairy matrices. In this study, a lytic bacteriophage specific to S. marcescens, designated ØAS2, was isolated from sewage samples collected in Assiut, Egypt. Phage ØAS2 was characterized using plaque assays, transmission electron microscopy (TEM), host range determination, pH and thermal stability tests, and one-step growth curve analysis. Its ability to inhibit bacterial growth and disrupt biofilms was also evaluated in vitro. TEM revealed that ØAS2 possesses an icosahedral head approximately 47.2 nm in diameter and a very short tail, consistent with the morphology of a member of the class Caudoviricetes that exhibits podovirus-like morphology. The phage exhibited a broad host range, infecting various Serratia strains as well as other Gram-negative bacteria, including Klebsiella spp., Escherichia coli, Salmonella typhi, and Shigella spp. ØAS2 was thermostable up to 60 °C and showed maximum activity at pH 8. One-step growth curve analysis revealed a short latent period of 10 min and a burst size of 115 PFU per infected cell. ØAS2 effectively inhibited the growth of S. marcescens SM02 in vitro and significantly reduced preformed biofilms at different multiplicities of infection (MOIs). When applied to skim milk and fresh soft cheese at various MOIs (Multiplicities of Infection), the phage successfully controlled bacterial contamination under refrigerated storage (7 °C for 7–10 days). At MOI 5.0, phage ØAS2 reduced biofilm biomass by 25.6%, planktonic growth by 85.7%, and achieved a reduction of 2.1 log₁₀ CFU/mL in skim milk. These findings indicate that ØAS2 is a promising biocontrol candidate for managing S. marcescens spoilage in dairy products. Full article

Nontuberculous mycobacteria (NTM) are environmental opportunistic pathogens with increasing clinical relevance worldwide. Among them, the Mycobacterium avium complex (MAC), comprising species such as M. avium, M. intracellulare, and M. chimaera, is responsible for the majority of human NTM diseases. MAC causes chronic pulmonary disease and disseminated infections, particularly in immunocompromised individuals, although infections in immunocompetent hosts are increasingly reported. Despite advances in molecular diagnostics, accurate species- and subspecies-level identification remains challenging due to high genetic diversity and biased genomic databases. This limitation hampers the understanding of transmission dynamics, antimicrobial resistance patterns, and epidemiological trends. In recent years, whole-genome sequencing (WGS) has emerged as a key tool for high-resolution typing, enabling improved phylogenetic analysis, outbreak investigation, and resistance prediction. This review summarizes current knowledge on MAC taxonomy, clinical manifestations, antimicrobial resistance mechanisms, and ecological distribution, with a particular focus on the role of genomic surveillance. We highlight the need for integrated genomic frameworks to support early detection, accurate classification, and effective public health surveillance of MAC infections globally in a One Health perspective. Full article

One of the most pressing challenges facing healthcare today is the rise of biofilm infections and antibiotic-resistant bacteria, which demand entirely new therapeutic strategies beyond conventional antibiotic reliance. A biofilm is a structured community of microorganisms encased in a self-produced extracellular polymeric substance (EPS) matrix, which confers resistance to host immune defenses and antimicrobial agents. Accumulating evidence demonstrates that plant-derived secondary metabolites—including flavonoids, phenolic acids, tannins, terpenoids, and alkaloids—exert potent antibacterial and antibiofilm activities through diverse mechanisms of action. These natural compounds inhibit biofilm formation by disrupting bacterial adhesion, suppressing quorum sensing, degrading the EPS matrix, and impairing bacterial motility. Beyond independent bioactivity, phytochemicals demonstrate significant synergistic potential when combined with conventional antibiotics, revitalizing antimicrobial efficacy against drug-resistant pathogens. Nanoformulation and biogenic carrier technologies further enhance the bioavailability and therapeutic potency of these compounds. Despite these advances, critical challenges persist, including poor bioavailability, physicochemical instability, dose-dependent toxicity, and the risk of resistance development. This review presents a critical and integrative analysis of the pharmacological mechanisms of plant secondary metabolites, with particular emphasis on their role in combating biofilm-associated infections and antibiotic resistance, and discusses translational opportunities including structure–activity relationship (SAR)-guided optimization, high-throughput screening platforms, and advanced drug delivery systems. Collectively, plant secondary metabolites represent a scientifically compelling and clinically relevant pipeline for the development of next-generation antimicrobial and antibiofilm therapeutics. Full article

Plague remains a globally important zoonotic disease maintained in natural foci, with ongoing epizootic activity and periodic human cases reported in several regions of the world. Continuous monitoring of antimicrobial susceptibility in Yersinia pestis is essential because the emergence of resistant strains could compromise the effectiveness of currently recommended therapeutic regimens. In this study, 75 Y. pestis isolates originating from natural plague foci of Kazakhstan were investigated using an integrated approach combining phenotypic susceptibility testing, targeted molecular screening, and whole-genome sequencing (WGS)-based resistome analysis. The collection included historical clinical isolates obtained during plague outbreaks as well as more recent epizootic strains recovered from animal hosts and flea vectors. Phenotypic testing demonstrated uniformly high susceptibility to clinically relevant antimicrobial agents used for plague treatment. Targeted molecular screening by real-time PCR did not detect the analyzed resistance determinants. Genome-wide analysis based on WGS data from NCBI BioProject PRJNA1249055 did not identify acquired antimicrobial resistance genes, major resistance-associated mutations in key chromosomal loci (rpsL, gyrA, and parC), or plasmid-borne resistance determinants. Regulatory loci associated with adaptive responses were highly conserved across the analyzed genomes. The complete concordance between phenotypic, molecular, and genomic findings indicates a stable antimicrobial susceptibility profile of Y. pestis circulating in natural plague foci of Kazakhstan. These results support the continued effectiveness of current therapeutic strategies for plague and highlight the value of integrating genomic surveillance into long-term monitoring programs for this pathogen. Full article