Antimicrobial resistance of two Escherichia fergusonii strains isolated from chicken feces

Abstract:

[Background] Escherichia fergusonii is a pathogen highly homologous to Escherichia coli, but its antimicrobial resistance has rarely been reported. [Objective] In this study, two E. fergusonii strains, EFCF053 and EFCF056, which were isolated from chicken feces in Zhejiang province, were tested and analyzed for antimicrobial resistance. [Methods] MICs were determined by microbroth dilution method. The whole genome sequences were obtained by using the next-generation sequencing, and acquired antimicrobial resistance genes were predicted via ResFinder database. Plasmids and resistance genes were identified by S1-PFGE and Southern blotting hybridization. [Results] It was found that both strains were resistant to ampicillin, gentamicin, florfenicol, sulfamidoxazole, trimethoprim/sulfamethoxazole and tetracycline. The strain EFCF056 was also resistant to colistin, ceftiofur, spectinomycin, enrofloxacin and ofloxacin. It was predicted that resistance genes existing in the strains were beta-lactam blaTEM-1A, blaCTX-M-65, blaOXA-1, blaTEM-1B, blaCTX-M-55; aminoglycoside aac(3)-IId, aph(3')-Ia, aph(3'')-Ib, aph(6)-Id, rmtB, aac(6')-Ib-cr, aadA2; colistin mcr-1; quinolone qnrS2, aac(6')-Ib-cr, oqxA, oqxB; fosfomycin fosA; macrolide mph(A); phenicol floR, catA1, catB3; rifamycin ARR-3; sulfonamides sul1, sul2, sul3, dfrA12, dfrA14; tetracycline tet(A). In addition, the data indicated that the plasmid harboring mcr-1 gene had the ability of conjugative transfer. [Conclusion] The results showed that E. fergusonii might be a reservoir of antimicrobial resistant genes. It is necessary to distinguish it from E. coli in the epidemiology of antimicrobial resistance. Further studies are needed to investigate the MIC frequency distribution, important drug resistance genes mcr-1 and ESBL for ensuring the accuracy of clinical detection.

Key words:Chicken feces, Escherichia fergusonii, Antimicrobial resistance gene, mcr-1