Genomic Characterization of --Carrying Foodborne serovar Typhimurium and Identification of a Transferable Plasmid Carrying -, , , and Genes From Ready-to-Eat Pork Product in China.

resistant to colistin, third-generation cephalosporins (3GCs), and fluoroquinolones (FQs) has been deemed a high-priority pathogen by the World Health Organization (WHO). The objective of this study was to characterize 11 --harboring serovar Typhimurium isolates from raw pork and ready-to-eat (RTE) pork products in Guangzhou, China. All isolates were multi-drug resistant and contained 6-24 antibiotic-resistant genes. The - gene was localized in the most conserved structure (-- ) in eight isolates and in mobile structure (IS--- ) in three isolates. One raw pork isolate SH16SF0850, co-harbored -, , and genes. One isolate 17Sal008 carried -, , , and genes located on a 298,622 bp IncHI2 plasmid pSal008, which was obtained from an RTE pork product for the first time. The pSal008 was closely related to a plasmid in an isolate from a 1-year-old diarrheal outpatient in China and was found to be transferable to J53 by conjugation. Genome sequence comparisons by core-genome Multi Locus Sequence Typing (cgMLST) based on all isolates from China inferred highly probably epidemiological links between selected pork isolates and no possible epidemiologically links between RTE pork isolate 17Sal008 and other isolates. Our findings indicate that raw pork and pork products are potential reservoirs of -harboring and highlight the necessity for continuous monitoring of colistin, 3GCs, and FQs resistant from different origins.