Search Results (258)

Culture-independent techniques are playing a major role in exploring unique and novel microbial communities from complex ecosystems, leading to an outstanding impact on our basic understanding of the tree of life. Microbial communities are not extensively studied in layer chicken housing environments, particularly from the point of view of taxa carrying antimicrobial resistance genes, virulence genes and their functional potential. This study aimed to extract metagenomic-assembled genomes (MAGs) from the Illumina short-reads shotgun metagenomics sequenced data that originated from an Alberta poultry barn environment and then to study host tracking of antimicrobial resistance genes (ARGs) and the roles of genes involved in functions related to ammonia production, short-chain fatty acid (SCFA)-related pathways, sulfur metabolism, methane emission, stress and disinfectant-related pathways. A total of 251 high-quality MAGs were extracted, including 249 bacterial and two archaeal genomes from sequencing data of 30 metagenomic sequencing samples comprising 15 air and 15 manure samples collected from 15-layer farms. Interestingly 22 bacterial MAGs were not classified to species levels using GTDB-based classification. ARGs were mainly harbored by the genera Staphylococcus, Alistepes, Romboutsia, and Enterococcus. Bacteroides is a main taxon carrying ARGs in air samples. Ammonia production-related genes were mainly tracked in Staphylococcus, Ruminococcus and Corynebacterium genera. The assimilatory sulfate reduction genes responsible for sulfur metabolism and hydrogenase-related genes responsible for hydrogen cycling were traced from Staphylococcus originated from both air and manure. The current study provides characterizations of MAGs from a poultry housing environment by linking microbial taxa with virulence, resistance, and metabolic functions. The findings emphasize the role of microbiota in shaping gas emissions and AMR, with implications for poultry health and worker’s safety and the ultimate aim of sustainable poultry production. Full article

Candidatus Hepatincolaceae is a poorly characterized family of obligate Alphaproteobacterial symbionts that are widely detected in ecdysozoans. They were previously assumed to play a nutrient-scavenging role in the gut lumen. In this study, two high-quality metagenome-assembled genomes (MAGs, 1.39 Mb and 1.48 Mb in size) were recovered from the gut of the snapping shrimp Alpheus brevicristatus via metagenomic sequencing. Phylogenetic and whole-genome similarity analyses confirm that these two MAGs represent two novel, undescribed genera within the family Ca. Hepatincolaceae. Metabolic reconstruction reveals that they not only retain the canonical nutrient-scavenging pathways conserved across all Hepatincolaceae members, but also encode previously undocumented functional modules for antioxidant defense, vitamin B₁ and B₂ biosynthesis, and short-chain fatty acid production. They maintain a high oxygen-affinity cytochrome bd terminal oxidase to thrive in the anoxic gut microenvironment. Consistent with their symbiotic lifestyle, their genomes exhibit typical signatures of reductive evolution, such as reduced genome size, low GC content, and gene loss in amino acid and nucleotide de novo biosynthesis pathways. This study presents the first reported high-quality genomes of marine Ca. Hepatincolaceae symbionts, which are predicted to possess multiple metabolic functions extending beyond nutritional mutualism. Full article

Raccoon dog and fox amdoparvovirus (RFAV) has been reported in raccoon dogs and foxes, but natural infection in domestic dogs has not previously been documented. During March–April 2026, samples from four affected Dobermann dogs from a kennel near Novi Sad, Serbia, were submitted for laboratory investigation. After negative testing for canine adenovirus, canine coronavirus, herpesvirus, parvovirus, distemper virus, influenza A virus, and leptospirosis, metagenomic sequencing was performed on selected tissues, followed by bioinformatic analysis and targeted RFAV PCR screening of additional outbreak-associated samples. Affected dogs had prolonged illness characterized by conjunctivitis with ocular and nasal discharge, occasional blue eye appearance, progressive weight loss, poor coat quality, jaundice and biochemical evidence of hepatic injury, and neurologic signs including paraplegia in advanced cases. Sequencing generated 434,220 reads and identified multiple RFAV hits; pooled assembly produced a 4799 bp consensus genome with approximately 97% similarity to known RFAV strains and genome organization consistent with the genus Amdoparvovirus. RFAV DNA was subsequently detected by virus-specific PCR in an epidemiologically linked dog and across diverse specimen types including blood, urine, kidney, spleen, brain, lung, testicle, ileocecal lymph node, and throat swabs, whereas clinically healthy unrelated dogs were PCR-negative. Full article

Background/Objectives: Antimicrobial resistance in microbial communities is a global health concern that leads to millions of deaths each year. Many bacterial pathogens have resistance to multiple antibiotics. Domestic wastewater treatment facilities are reservoirs for antibiotic-resistant bacteria and resistance genes. Wastewater-based epidemiology surveillance is crucial for monitoring antibiotic resistance genes (ARGs). Türkiye has one of the highest levels of antibiotic resistance with a lack of research on resistomes. This study is a focused reanalysis of publicly available wastewater metagenomes from Türkiye, comparing them to global and other country’s results. Methods: Ten metagenomic data of wastewater treatment from Türkiye were downloaded from NCBI-SRA database. Metagenome assemblies were performed and high-quality metagenome-assembled genomes (HQ-MAGs) were included in the study. Taxonomic annotations and antibiotic resistance profiles were identified in both the metagenome assemblies and HQ-MAGs. Results: A total of 401 different ARGs in 25 antibiotic classes have been identified, including Mcr (including mcr-1, mcr-2, mcr-3 and mcr-5 variants) and optrA. The vanR two-component regulatory system genes for controlling vancomycin antibiotic resistance were one of the most dominant along with other vancomycin resistance genes such as vanA and vanB. A total of 115 HQ-MAGs were obtained with at least eight ARGs. The HQ-MAG with the highest number of resistance genes (58) was found to belong to E. coli. The most frequently encountered resistance genes in HQ-MAGs were the multidrug ABC transporter, vanR, bacA and patA which confer resistance to multidrug, glycopeptide, bacitracin and fluoroquinolone antibiotic groups, respectively. Conclusions: To effectively address the problems of antibiotic resistance outbreaks, comparable AMR surveillance at national and global levels is required for the identification and prioritization of ARGs and resistance genes. This is the first report conducted in Türkiye. Full article

Geothermal ecosystems constitute important reservoirs of thermophilic microorganisms and their associated metabolic functions; however, the genome-resolved diversity and enzymatic potential of high-altitude geothermal systems remain poorly characterized. Here, we applied shotgun metagenomics and genome-resolved approaches to investigate thermophilic microbial communities inhabiting geothermal sediments from the El Tatio geothermal field, a polyextreme hydrothermal system located at ~4300 m above sea level in the Andean Altiplano of northern Chile. Genome reconstruction yielded 657 metagenome-assembled genomes (MAGs), including 190 near-complete and 273 high-quality genomes, providing a comprehensive genome-resolved view of microbial diversity in this environment. Taxonomic analyses revealed diverse archaeal and bacterial communities dominated by members of Thermoproteota, Methanobacteriota, Deinococcota, and Actinomycetota. Functional screening identified 612 high-confidence putative hydrolase-encoding genes distributed across multiple thermophilic lineages, including genes associated with esterases, lipases, proteases, and glycoside hydrolases. Notably, several candidates were recovered from archaeal MAGs affiliated with Thermoproteus, Sulfolobales, Pyrobaculum, and Acidilobaceae, expanding the genomic repertoire of putative hydrolytic functions in thermophilic archaea. Sequence-based thermostability prediction identified proteins with estimated melting temperatures exceeding 80 °C, with the highest predicted value reaching 87.6 °C. Collectively, these results expand current knowledge of microbial diversity and functional potential in high-altitude geothermal ecosystems and identify El Tatio as a rich source of putative hydrolase-encoding genes for future biochemical and biotechnological exploration. Full article

Metagenomic analysis of extreme environments is essential in biotechnological research. This work aimed to determine and compare the microbial diversity of two Peruvian saline environments and characterise their functional profiles. Soil metagenomic DNA (mDNA) was analysed from Maras and Pilluana salterns, both with a thalassohaline origin but with different geographical and environmental conditions. Maras samples exhibited more diversity and a remarkably higher abundance of archaea (phylum Euryarchaeota). The most dominant bacterial phyla across all the samples were Pseudomonadota and Actinomycetota. Multiple pathways specific to archaea were more abundant in Maras, as were pathway-related synthesis and degradation of compatible osmolytes such as glycine betaine and ectoine. The most abundant pathways in Pilluana were associated with fatty acid biosynthesis and oxidation. A total of 49 and 47 metagenomic-assembled genomes (MAGs) were retrieved from Maras and Pilluana samples, respectively. Bacterial MAGs were mainly classified within the phyla Psudomonadota, Actinomycetota, Planctomycetota, and Gemmatimonadota. Additionally, a total of 20 putative aminotransferases class III (ATs, PF00202) from Maras3 were cloned and expressed in E. coli Rosetta, and their substrate scoping was assayed against several aldehyde and ketone substrates; AT pQR3082 and pQR3090 showed unique broad substrate acceptance for aromatic and aliphatic substrates. Our study provides new insights into the microorganisms and metabolic pathways of these unique extreme environments, highlighting the promising biotechnological potential of metagenomic ATs. 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

The dissemination of antibiotic resistance genes (ARGs) in riverine ecosystems poses a pressing public health threat, while the mechanisms governing the assembly of the gut resistome in wild fish remain poorly elucidated. This study aimed to elucidate the distributional patterns of ARGs across multiple environmental compartments and to identify factors associated with their variation, particularly the contributions of mobile genetic elements (MGEs) and metal resistance genes (MRGs) to gut resistome variation. Metagenomic sequencing was conducted on 60 samples, comprising water, sediment, and gut contents from three wild fish species (Megalobrama terminalis, Aristichthys nobilis, and Coilia nasus) with distinct feeding habits, collected from four reaches of the Qiantang River basin. A total of 305 ARG subtypes belonging to 23 classes were identified. ARG composition differed significantly across environmental media and host species (permutational multivariate analysis of variance, PERMANOVA; p < 0.01), with host species identity as the primary structuring factor. Variance partitioning analysis (VPA) revealed that MGEs independently explained the largest fraction of ARG variation in A. nobilis (33.8%, p = 0.006), whereas MRGs dominated in C. nasus (33.3%, p = 0.005); in M. terminalis, MGEs and MRGs together accounted for 47.9% of the variation. Metagenomic assembly recovered 2622 ARG-carrying contigs, of which 28.3% (743) were predicted as plasmid sequences; physical co-localization among ARGs, MGEs, and MRGs was detected on both chromosomes and plasmids. Metagenomic binning validated the physical co-localization of ARG-MGE-MRG modules in genera such as Morganella and Burkholderia at the genome level, while plasmid-borne high-risk ARGs were identified in Aeromonas. Risk ranking further revealed significant enrichment of Rank II potentially high-risk ARGs (e.g., mcr-7.1, blaZ) in fish guts, carried by potential pathogens. These findings suggest that horizontal gene transfer involving MGEs and co-selection related to MRGs are closely associated with the fish gut resistome composition in a manner dependent on host ecology, providing a scientific basis for shifting riverine resistance management from concentration-based control toward the interruption of dissemination pathways. Full article

Herpes simplex virus 1 (HSV-1) is a rare cause of acute hepatitis, especially in patients with chronic immunosuppression. We performed whole-genome HSV-1 sequencing with a metagenomics approach on peripheral blood samples from an Italian case of fatal acute liver failure with high circulating HSV-1 (1,129,900,000 copies/mL), followed by phylogenetic analysis. After multiple sequence alignment, a final dataset of 182 whole-genome sequences was selected. The sequenced HSV-1 strain belonged to a phylogenetic clade isolated in Florida in 2002 (OQ724868.1). A characterization of single nucleotide polymorphisms and indels was performed to determine their effects on the viral genome: only one variant, classified as an indel, was detected with a high impact effect (c.905_906insGTTTT) in the UL49A gene, which is known to encode a membrane protein regulating virion morphogenesis, replication and assembly. In addition, this study also detected variants in other genes involved in crucial steps of the HSV-1 life cycle, like alpha-regulation (US7), capsid transport (UL36) and viral polymerase function (UL30). In conclusion, the results of this variant analysis confirmed that in HSV-1 hepatitis, some viral regions may be hotspots for adaptive mutations with a substantial impact on viral replication or immune evasion. Full article

Soils are critical microbial habitats that support terrestrial ecosystem functioning and harbor numerous uncultured and functionally uncharacterized microbial groups. The black soil region in northeast China is a key agricultural ecosystem globally, yet the classification and functional understanding of its crucial microbial groups remain underexplored. In this study, we identified three high-completeness metagenome-assembled genomes (MAGs) from the Global Mollisols Genomic Atlas (GMGA). Phylogenetic and comparative genomic analyses identified these genomes as representing a novel evolutionary branch within the genus Flavobacterium, classified under the phylum Bacteroidota. Their novel taxonomic position is further supported by average nucleotide identity (ANI) and average amino acid identity (AAI) thresholds, demonstrating significant divergence from all known reference genomes. Functional annotation indicated that this species possesses strong plant polysaccharide degradation potential and a chemoheterotrophic lifestyle, together with environmental stress tolerance and a specialized nitrogen metabolic network adapted to agricultural inputs, thereby conferring a metabolic advantage in black soil environments characterized by high organic matter input and marked seasonal fluctuations. In addition, global distribution analysis showed that this lineage is widely distributed across diverse ecosystems and is significantly enriched in soil habitats, particularly in environments with fluctuating carbon sources and high organic matter inputs. The new species is most abundant in temperate soils, with the northeast black soil region of China emerging as a key hotspot. Based on these findings, and because no pure culture is currently available, we propose Candidatus Flavobacterium genomatis based on genome-resolved metagenomic evidence and in alignment with the International Code of Nomenclature of Prokaryotes rules for uncultivated prokaryotes. Our results expand the known species diversity of the genus Flavobacterium and suggest potential ecological roles of uncultured black-soil microbes in carbon and nitrogen cycling, including possible involvement in N₂O reduction under suitable environmental conditions. Full article

Under a One Health framework, viruses of veterinary and zoonotic importance pose significant threats to animal and human health, food security, and livelihoods, particularly in regions with intense human–animal interactions. In West Africa, despite recent advances in surveillance programs, important gaps remain in understanding viral diversity and cross-species transmission at wildlife–livestock interfaces. We conducted metagenomic surveillance to characterize viruses circulating across livestock, domestic animals, and wildlife in rural Ghana in 165 animals sampled across five regions. Viral RNA from serum and tissue samples was sequenced with the Illumina platform, and genomes were de novo assembled with MEGAHIT. Phylogenetic relationships were reconstructed using Bayesian approaches. We report the first genomic sequences of porcine parvovirus 3, canine parvovirus, rotavirus A genotype R16, and bovine hepacivirus subtype B from Ghana in over a decade. Phylogenetic analyses revealed intercontinental linkages between Africa and Europe for parvoviruses, persistence of hepacivirus lineages, and evidence of cross-species transmission for rotavirus. Notably, detection in apparently healthy animals highlights underrecognized circulation, gaps in vaccination effectiveness, trade-related biosecurity vulnerabilities, and the role of wildlife in viral maintenance and transmission. Our findings reveal dynamic viral diversity and connectivity across animal populations and ecological interfaces, emphasizing the fluid and interconnected nature of pathogen circulation within One Health systems. By integrating metagenomics and phylogenetics, this study provides a scalable framework for enhancing surveillance capacity, enabling the early detection of emerging threats and informing targeted strategies to mitigate zoonotic and economically important viral diseases in West Africa. Full article

Abortion in cattle entails substantial economic loss, and rapid identification of abortigenic pathogens is critical for timely on-farm response and reduction in human exposure risk. In 2024, two Holstein cows from a small farm in Inner Mongolia aborted in close succession without an obvious cause. Vulvar swabs from both cows, one afterbirth sample, and whole blood from one aborted fetus were collected. Shotgun metagenomic sequencing was performed, followed by host-read removal, taxonomic profiling with Kraken2, de novo assembly of Brucella-aligned reads, and whole-genome comparison. Serological tests, Gram-stained smears, and Brucella genus- and species-specific qPCR assays were used as orthogonal verification. Putative resistance and virulence determinants were screened against CARD and VFDB. Brucella reads were detected in all samples, with the highest relative abundance in the 138-afterbirth (96%). qPCR assays detected Brucella DNA and B. abortus-specific signals in all four samples. A draft Brucella genome was assembled from the 138-afterbirth sample and was phylogenetically placed within B. abortus, showing relatedness to previously circulating Chinese lineages. Cows 138 and 198 were RBT-positive with SAT titres of 1:100 (++). No acquired Brucella resistance genes were identified in CARD. Within 72 h of sample receipt, B. abortus was reported to the farm and local authorities and emergency biosecurity measures were implemented. This field investigation shows that metagenomic sequencing, when combined with conventional serology, microscopy, and targeted qPCR, can support rapid etiological investigation when culture is delayed, hazardous, or biosafety level 3 facilities are unavailable. Full article

Background/Objectives: Probiotic feed additives are increasingly used in livestock production as antimicrobial-sparing tools, yet viable microbial products should not introduce clinically relevant antimicrobial resistance genes (ARGs) into the intestinal resistome. This study evaluated farm-animal probiotic products using an integrated phenotypic, metagenomic and mobilome-aware safety framework. Methods: Seven commercially available products intended for poultry, pigs, cattle or horses were assessed using product metadata, culture-based recovery, broth microdilution minimum inhibitory concentration (MIC) profiling and Illumina short-read sequencing as a screening-level resistome approach. Reads were quality controlled, assembled, screened using the Comprehensive Antibiotic Research Database (CARD)/Resistance Gene Identifier (RGI) workflow and interrogated for plasmid-, phage- and insertion sequence/mobile genetic element-associated genomic context. Results: MIC profiles were generated for viable bacterial isolates representing Enterococcus faecium, Pediococcus acidilactici, Pediococcus pentosaceus and Bacillus subtilis. One labelled Lactobacillus plantarum component was not recovered as viable culture, and one labelled P. acidilactici component was recorded as P. pentosaceus. Sequencing-based resistome screening identified 30 antimicrobial resistance (AMR)-associated CARD antibiotic-resistant organism (ARO) hits belonging to 13 determinants across six ARG-positive coded products, while one coded product had no retained CARD/RGI hit. Profiles were dominated by recurrent Enterococcus-associated background determinants, including aac(6′)-Ii, msrC and eatAv. Plasmid prediction was positive for five hits, whereas no iMGE- or phage-associated ARG context was detected. No vanA/vanB, mcr, optrA, poxtA, cfr, extended-spectrum β-lactamase (ESBL) or carbapenemase gene was detected. Conclusions: The investigated products did not show evidence of high-priority mobile ARG carriage. Nevertheless, AMR-associated determinants and occasional predicted mobile contexts support routine integrated MIC-sequencing-based resistome–mobilome assessment of veterinary probiotic products. Because short-read assemblies do not fully resolve plasmid architecture or transferability, mobile-context predictions should be considered screening-level indicators requiring confirmatory long-read or functional testing for higher-priority findings. Full article

The double-crested cormorant (Nannopterum auritum), a piscivorous bird endemic to North America, frequently forages in aquaculture ponds during migration and wintering, contributing to economic losses in catfish-producing regions of the southern United States. While interactions between cormorants and aquaculture systems are well documented, their associated microbial communities and genetic elements remain less characterized. In this exploratory study, Hi-C-enabled metagenomics was applied to fecal samples from two cormorants to generate a genome-resolved, descriptive analysis of gut microbial composition and to associate bacterial genomes with mobile genetic elements (MGEs), antimicrobial resistance genes (ARGs), and putative virulence-associated genes. Metagenome-assembled genomes (MAGs) included taxa reported in aquatic or animal-associated environments, including Edwardsiella tarda, Plesiomonas shigelloides, Clostridium perfringens, and Campylobacter volucris. ARGs were detected across multiple MAGs, with E. tarda harboring the greatest diversity. Hi-C-enabled linkage of plasmids and phages to putative hosts, providing structural insight into microbial organization. Analyses are descriptive (n = 2) and do not include statistical comparisons or diversity metrics. These findings demonstrate the utility of Hi-C for resolving gene–host associations and provide a framework for future studies of microbial connectivity in One Health contexts. Full article

Hospital wastewater treatment efficacy is conventionally assessed by total antibiotic resistance gene (ARG) abundance; however, whether this metric accurately reflects biosafety risk remains poorly defined. Using a one-year longitudinal metagenomic survey (bimonthly sampling; n = 18 per group), we simultaneously profiled the resistome, virulome, and mobilome of hospital wastewater influent and effluent; stratified functional gene abundances by genomic origin; quantified ARG–mobile genetic element (MGE) colocalization; and characterized multicategory gene cocarriage across the 15 most abundant pathogenic species. Although the abundance of total strict ARGs decreased significantly in the effluent (p = 0.038), the abundances of metal resistance genes and virulence factors increased concurrently (both p < 0.01), and 8 of the 20 ARG subtypes were enriched rather than removed. This decline was driven exclusively by a reduction in the number of plasmid-encoded ARGs (p < 0.001), whereas genes encoding chromosomal virulence factors, metal resistance genes, biocide resistance genes, and MGEs were significantly enriched in the effluent (all p < 0.05). The normalized ARG–MGE colocalization rate was significantly greater in the effluent (p = 0.028), with a concurrent shift toward transposase-mediated chromosomal mobilization. Pathogen-associated metagenomic assemblies of clinically relevant species exhibited synchronous multicategory resistance coenrichment in the effluent, which is consistent with coselection under antibiotic, biocide, and metal pressures. Total ARG abundance is fundamentally decoupled from biosafety risk in treated hospital wastewater, warranting integrated surveillance beyond ARG-centric metrics. Full article