Drug Resistance and Genetic Relatedness of Escherichia coli from Mink in Northeast China

Abstract

To analyze the drug resistance and Pulsed Field Gel Electrophoresis (PFGE) typing of Escherichia coli (E. coli) from mink, this study collected healthy mink feces from four farms in Northeast China (Liaoning Province, Jilin Province and Heilongjiang Province) from 2016 to 2019. 126 E. coli strains ranging from 155 mink feces were identified by laboratory isolation and culture and 16S rDNA PCR and sequencing analysis. All strains were subjected to antimicrobial susceptibility testing using the Kirby-Bauer disc diffusion method and PFGE to determine their genomic relatedness. The results showed that 126 strains had different rates of resistance to 15 antimicrobials. They were highly resistant to ampicillin, tetracycline, doxycycline, chloramphenicol and cotrimoxazole, with resistance rates above 60%; they were more susceptible to amikacin, amitriptyline, doxycycline, gentamicin and imipenem, with sensitivity rates above 60%. 26 randomly selected highly resistant strains had different PFGE typing, and 14 of them had homology coefficients lower than 50%. These results suggest that mink-derived E. coli in the Northeast China have antimicrobial resistance and high genetic diversity.