Plasmid-Encoded Gene That Confers High-Level Carbapenem Resistance in Typhimurium of Pork Origin.

Purpose: Carbapenem resistance is rarely reported in Typhimurium, especially from a food origin. Here, we report a plasmid-mediated mobile carbapenem-resistant gene in Typhimurium isolated from pork in Shanghai, China in 2016.

Patients And Methods: In July 2016, the . Typhimurium SH160 strain was recovered from minced pork meat purchased from a supermarket in Yangpu District, Shanghai, China. Antimicrobial susceptibility testing, multi-locus sequence typing, conjugation, S1-PFGE, southern hybridization, whole-genome sequencing and data analysis were performed.

Results: This isolate was found to be a ST34 strain and resistant to carbapenems, cephalosporins, and most other commonly used antibiotics. The gene was harbored by a 46161-bp IncX3 plasmid which was found to be transferable. The IncX3 plasmid contains a composite cassette, consisting of . In addition, this strain was found to harbor an additional 161706-bp IncHI2 plasmid which carries nine resistant genes, such as and .

Conclusion: We reported the Typhimurium with transferable IncX3 plasmid harboring gene from minced pork. We characterized the complete genetic features of the plasmid, which demonstrated the potential for spreading in different bacterial pathogens. Therefore, extensive surveillance and monitoring for carbapenem-resistant bacterium in the food chain and public health are urgently required.