IncX3 plasmid carrying blaSHV-12 and qnrS1 in a Japanese racehorse-origin Escherichia coli isolate

Abstract

Plasmids play an important role in the spread of antimicrobial resistance genes (ARGs) in bacteria. This study reports the complete sequence of the IncX3 plasmid identified in Escherichia coli isolated from faeces of a Japanese racehorse. Sequence analysis revealed that this plasmid harbours the blaSHV-12 gene, which encodes an extended spectrum ?-lactamase, and the quinolone resistance gene qnrS1. The IncX3 plasmids carrying ARGs have been previously identified in bacteria isolated from humans, animals and a variety of environments. This is the first report of the complete sequence of the IncX3 plasmid carrying blaSHV-12 and qnrS1 genes from a Japanese racehorse, which provides insights into understanding the spread and mechanism of antimicrobial resistance particularly in Japanese racehorses.