Characteristics of Two -Harboring IncHI2 Plasmids from Clinical Isolates in Jiaxing City.

is a primary cause of foodborne diseases, and the increasing prevalence of carrying plasmids, which confer colistin resistance to , poses significant global health concerns. As the frequency of occurrence of the gene is increasing globally, we studied the prevalence of in clinical isolates by analyzing 195 clinical strains isolated in 2020. Of the 195 isolates, 41 isolates were resistant to colistin. We found in two strains ( Typhimurium ZJJX20006 and Kentucky ZJJX20014), which we analyzed in detail via whole-genome sequencing and antibiotic susceptibility testing. Two strains displayed resistance to ampicillin, ampicillin-sulbactam, tetracycline, chloramphenicol, and cotrimoxazole, while ZJJX20006 displayed resistance to colistin and ZJJX20014 was sensitive. Genomic analysis revealed that these strains had plasmid-encoded in IncHI2 plasmids, which were not similar to the -IncX4 identified in 2016. These two strains also harbored other drug resistance genes, including and . Our findings may help clarify the molecular mechanisms of dissemination among strains in Jiaxing City and offer insights into the evolution of in .