Antibiotic resistance, serogroups, virulence genes, and phylogenetic groups of isolated from yaks with diarrhea in Qinghai Plateau, China.

BACKGROUND

Ruminants serve as one of the most important reservoirs for pathogenic Infection with , a foodborne enteropathogen, can lead to asymptomatic infections that can cause life-threatening complications in humans. Therefore, from a clinical and human health perspective, it is important to know which virulence genes, phylogenetic groups, serogroups, and antibiotic resistance patterns are present in strains in yaks with diarrheic infections.

METHODS

Two-hundred and ninety-two rectal swabs were collected from diarrheic yaks in Qinghai Plateau, China. The antimicrobial sensitivity of each resulting isolate was evaluated according to the disk diffusion method, and different PCR assays were performed for the detection of virulence genes and different phylogroups. Additionally, strains were allocated to different serogroups based on the presence of O antigen via the slide agglutination method.

RESULTS

Among the isolates tested, most of the isolates were multidrug resistant (97%) and harbored at least one virulence gene (100%). We observed ten virulence genes (, and ), of which was the most commonly found (96.9%). Significant positive associations between some resistance phenotypes and virulence genes were observed ( < 0.05, OR > 1). The majority of the isolates belonged to phylogroup A (79.5%), and the others belonged to phylogroups B1 (7.5%), D (4.1%), B2 (5.8%), and F (0.7%). Among all the strains tested, serogroups O and O were the most prevalent, accounting for 15.4 and 14.4%, respectively.

CONCLUSIONS

Our results suggest that yaks with diarrhea serve as a reservoir of pathogenic carrying various virulence genes and resistance phenotypes. Therefore, clinicians and relevant authorities must ensure the regulatory use of antimicrobial agents and prevent the spread of these organisms through manure to farm workers and food-processing plants.