Antimicrobial susceptibility and multilocus sequence typing of isolated from yaks in Qinghai-Tibet plateau, China.

is an opportunistic pathogen that cause necrotic enteritis, food poisoning and even death in animals. In this study, we explored the prevalence, antibiotic resistance and genetic diversity of isolated from yak in the Qinghai-Tibet plateau, China. A total of 744 yak fecal samples were collected and assessed for toxin genes, antimicrobial susceptibility and multilocus sequence typing (MLST). Results indicated that 144 out of 744 (19.35%) yak fecal samples were tested to be positive for , 75% ( = 108, 108/144) were type A, 17.36% ( = 25, 25/144) were type C, 2.78% ( = 4, 4/144) were type D, and 4.86% ( = 7, 7/144) were type F. In addition, 2.78% ( = 4, 4/144) of the isolates were positive for toxin gene. Antimicrobial susceptibility testing revealed that 98.61% (142/144) of the isolates showed multiple-antibiotic resistance. According to MLST and phylogenetic tree, 144 yak-derived isolates had an average of 12.95 alleles and could be divided into 89 sequence types (STs) and clustered in 11 clonal complexes (CCs). The most of isolates belong to type A with a considerable genetic diversity, having Simpson index up to 0.9754. MLST and phylogenetic analysis showed that the isolates under the same clade came from multiple regions. Cross-transmission among isolates and interconnectedness were observed in the genetic evolution. According to the study, the most of the isolates exhibited broad-spectrum antibacterial resistance, diverse alleles, and multiple lethal toxin genes of .