Insights into the Genetic Diversity of Yersinia enterocolitica Isolated from Poultry and Red Meat in South Korea in 2024

Comprehensive Genomic Analysis of the pO157 Plasmid in Enterohemorrhagic Escherichia coli O157:H7 Reveals Non-synonymous Variation in Virulence Factors

Genomic Insights Into Bacillus thuringiensis Strain JSd1 From Bangladesh: A Whole Genome Sequencing Approach

The findings suggest that B. thuringiensis JSd1 is a promising candidate for development as a biopesticide targeting insect pests in Bangladeshi agriculture, and lays the groundwork for further functional validation and field applications, contributing to sustainable pest management strategies in the region.

Emergence of an optrA-positive Enterococcus faecalis ST699 lineage in animal-derived foods in Beijing, China.

Enterococci from animal-derived foods are key reservoirs for antimicrobial resistance (AMR) in the food chain. However, comparative genomic studies investigating the distribution of the oxazolidinone resistance gene optrA among food- and human-derived Enterococci remain limited. This study assessed linezolid-resistant Enterococci from retail meat and healthy humans in Beijing, China (2023-2024). Among 87 isolates, E. faecalis and E. faecium predominated. Food-derived isolates showed broader resistance profiles than human isolates. Fourteen optrA-positive strains were identified, accounting for 92.9% of food isolates. optrA frequently co-localized with erm(A), ant(9)-Ia, and fexA on Tn554-family transposons, suggesting a potentially transferable multidrug resistance module. Notably, an optrA-positive E. faecalis ST699 clone was identified for the first time in Chinese retail meat. This clone formed a distinct lineage and carried a complete Tn554-optrA island. A representative ST699 isolate exhibited enhanced fitness and virulence potential in the Galleria mellonella model. These findings highlight animal-derived foods as important reservoirs of linezolid-resistant Enterococci and provide genomic evidence consistent with their role as potential sources of optrA-mediated resistance. The emergence of a multidrug-resistant E. faecalis ST699 clone with enhanced fitness characteristics underscores the need for continued surveillance of foodborne antimicrobial resistance within the One Health framework.

Genomic and One Health insights into Vibrio parahaemolyticus from environmental, seafood and clinical sources.

Vibrio parahaemolyticus is a leading cause of seafood-borne gastroenteritis worldwide, with climate warming facilitating its spread to high-latitude areas. In this study, we analyzed 212 genomes of environmental and seafood-associated isolates collected from seven cities in Zhejiang Province, China (2019-2024), alongside 228 clinical genomes from public databases. The 212 isolates were assigned to 172 sequence types (STs), with ST490 being the most frequent (5/212, 2.36%). Forty-four serotypes were identified, dominated by OL3:KUT (12.68%). High ST and serotype diversity were observed across different sample types and sources, with median pairwise single nucleotide polymorphisms (SNPs) ranging from 57,431 to 58,378, indicating comparable genetic diversity across groups. All isolates carried tlh and T3SS1 but lacked tdh and T3SS2. Resistance rates against ampicillin and cefazolin were 54.72% (116/212) and 44.34% (94/212), respectively, with multidrug resistance (MDR) detected in nine isolates, predominantly from seafood (7/9). A total of 63 distinct antimicrobial resistance genes (ARGs) spanning seven classes were identified. Isolates from aquaculture farms and wet markets exhibited greater resistance category diversity and higher ARG carriage than those from coastal or riverine sites. In contrast, the 228 clinical isolates harbored only 25 ARGs across two classes, with a significantly lower proportion of isolates carrying multiple ARG classes (0.44% vs. 6.13%, P < 0.001). Human isolates formed tighter phylogenetic clusters, although a minority were closely related to environmental/foodborne strains. Overall, our findings demonstrate the genetic diversity and resistance potential of V. parahaemolyticus across environmental, seafood, and clinical sources, highlighting the importance of the One Health approach to comprehensive public health risk assessment.

Isolation, Identification, and Biological Characterization of Proteus mirabilis Isolated from Beef Cattle in China

Proteus mirabilis, a member of the family Enterobacteriaceae, is widely distributed in the environment and commonly colonizes the gastrointestinal tract of animals. Although traditionally regarded as an opportunistic zoonotic pathogen, increasing evidence suggests that it may also contribute to bovine diseases. However, information regarding the antimicrobial resistance, virulence determinants, and genomic characteristics of bovine-associated P. mirabilis in China remains limited. In this study, a P. mirabilis strain, designated A3, was isolated from one of 19 diarrheic adult beef cattle sampled in Anhui Province, China, and comprehensively characterized through phenotypic, genomic, and pathogenicity analyses. Strain A3 exhibited typical swarming motility and a multidrug-resistant phenotype. PCR screening identified the resistance genes aac(6′)-Ib and qnrA, together with seven virulence genes (pmfA, atfA, ureC, mrpA, ucaA, zapA, and atfC) involved in adhesion and colonization. Whole-genome sequencing generated a 3,965,086 bp draft genome with a GC content of 38.37% and identified 85 resistance-associated genes and 147 virulence-associated genes, including multidrug efflux pumps and virulence factors related to adhesion, motility, iron acquisition, secretion systems, and host interaction. Comparative genomic analysis demonstrated high genomic similarity to other bovine-derived P. mirabilis isolates, with average nucleotide identity (ANI) values ranging from 99.06% to 99.32%, while pangenome analysis identified 5680 orthologous gene clusters, including 2959 core genes, indicating an open pangenome structure. Multiple insertion sequences, prophages, and genomic islands were identified, highlighting substantial genomic plasticity and adaptive potential. In a mouse infection model, strain A3 exhibited clear dose-dependent pathogenicity. All eight mice challenged with 2.22 × 109 CFU/mL died within 12 h post-infection and developed severe pathological lesions in multiple organs, whereas only one of eight mice in the low-dose group died during the same period. Collectively, these findings indicate that bovine-derived P. mirabilis A3 combines multidrug resistance, genomic plasticity, and opportunistic pathogenic potential. This study expands current knowledge of bovine-associated P. mirabilis and provides a genomic and experimental basis for surveillance, risk assessment, and prevention strategies in cattle production systems.

Whole-genome sequencing analysis of three Edwardsiella ictaluri isolates from Indonesia: genetic insights into virulence and resistance in pangasius farming