Characteristics of The Plasmid-Mediate Colistin-Resistance Gene Mcr-1 In Escherichia Coli Isolated from Pig Farm in Jiangxi

Abstract

To explore the prevalence and characteristics of MCRPEC in pig farms, 278 pig fecal samples were collected from a pig farm in Jiangxi Province. Ten MCRPEC strains were laboratory isolated by culture, PCR, and gel electrophoresis. The broth-microdilution was adopted for the drug sensitivity test. After whole-genome sequencing, the resistance genes and plasmid typing were analyzed, and the transferability of mcr-1 was verified through plasmid conjugation transfer. The results showed that all ten strains were resistant to colistin, gentamicin, florfenicol, trimethoprim, cefotaxime, and tetracycline, with a MDR rate of 100%. The ten MCRPEC strains were found to belong to seven STs, and mcr-1 was mainly located on the IncI2 plasmid, featuring a typical plasmid coupling transfer part, type IV secretion system, and antimonite protein gene; horizontal transfer occurred in nine strains. These results indicate that MCRPEC exists on this pig farm and is MDR. Bacterial monitoring should be strengthened, the use of antibiotics on farms should be reduced, and the spread of ARGs should be controlled.