[Antimicrobial resistance and genomic characteristics of Salmonella from diarrhea patients in Jiamusi City, 2015-2023].

This study collected fecal and blood samples from diarrhea patients at three hospitals in Jiamusi City between 2015 and 2023. After isolation and identification, 98 Salmonella strains were obtained, and whole-genome sequencing and annotation analysis were performed on these strains. The results showed that the 98 strains were classified into 23 serotypes, with Salmonella Enteritidis being the most common (44.89%, 44/98). The isolates exhibited resistance to streptomycin, ampicillin, tetracycline, and nalidixic acid. The multidrug resistance rate was 52.04% (51/98), and the mutation rate of the quinolone resistance-determining region was 57.14% (56/98). A total of 48 resistance genes belonging to 10 categories were detected, with the aminoglycoside resistance gene aac(6')-Iaa being the most prevalent (94.89%). Both the core genome multilocus sequence typing analysis and the phylogenetic analysis based on single nucleotide polymorphisms demonstrated a correlation with serotype, and the isolates were predominantly Salmonella Enteritidis. Virulence factors were predominantly associated with secretion systems and fimbrial adherence. In conclusion, in Jiamusi City, Salmonella Enteritidis is the dominant serovar, multidrug-resistant Salmonella is prevalent, aminoglycoside resistance genes are highly prevalent, chromosomal mutations dominate the resistance mechanism, genetic relatedness exists among the isolates, and virulence genes are abundant, indicating strong pathogenic potential.