“Chinese scientists find 2 MCR genes on same plasmid”

“Scientists in China have isolated a strain of Escherichia coli from commercial poultry that contains two colistin-resistance genes on the same plasmid, according to a study today in Antimicrobial Agents and Chemotherapy.

While multiple colistin resistance genes have been detected since the first, MCR-1, was identified in China in 2015, this is the first time that two of the genes have been found on the same plasmid. These mobile pieces of DNA can share resistance genes within and among different bacterial species and contribute to the rapid spread of colistin-resistant bacteria. Colistin is considered a last-resort antibiotic for multidrug-resistant infections.

The E coli strain, isolated from a chicken cloacal (anal area) swab in Sichuan province in 2015, contained MCR-1 and a variant of MCR-3, named MCR-3.11.

“The coexistence of the mcr-1 and mcr-3 genes in E. coli isolates may pose a huge threat to public health and warrant[s] further investigation,” the Sichuan University authors write.”

Source: CIDRAP