Various Sequence Types of Escherichia coli Isolates Coharboring <i>bla</i> _NDM-5 and <i>mcr-1</i> Genes from a Commercial Swine Farm in China

Abstract

Sixteen different sequence types (STs) of <i>Escherichia coli</i> isolates from a commercial swine farm in China were confirmed to coharbor the carbapenem resistance gene <i>bla</i>_NDM-5 and the colistin resistance gene <i>mcr-1</i> Whole-genome sequencing revealed that <i>bla</i>_NDM-5 and <i>mcr-1</i> were located on a 46-kb IncX3 plasmid and a 32-kb IncX4 plasmid, respectively. The two plasmids can transfer together with a low fitness cost, which might explain the presence of various STs of <i>E. coli</i> coharboring <i>bla</i>_NDM-5 and <i>mcr-1</i>.