两株分离自鸡粪便费格森埃希菌的耐药性

Antimicrobial resistance of two Escherichia fergusonii strains isolated from chicken feces

【背景】费格森埃希菌(Escherichia fergusonii)是与大肠杆菌同属、近源的病原菌,目前耐药性鲜有报道。【目的】对在浙江省鸡粪便中分离到的2株费格森埃希菌EFCF053和EFCF056进行耐药性检测和分析。【方法】通过微量肉汤稀释法进行MIC测定,二代高通量测序获得全基因组序列,并通过ResFinder数据库预测获得性耐药基因。利用S1-PFGE和Southernblotting杂交进行质粒和耐药基因的确认。【结果】两种菌均对氨苄西林、庆大霉素、氟苯尼考、磺胺异噁唑、复方新诺明、四环素耐药,其中菌株EFCF056还对粘菌素、头孢噻呋、大观霉素、恩诺沙星、氧氟沙星耐药。预测到耐药基因β-内酰胺类blaTEM-1A、blaCTX-M-65、blaOXA-1、blaTEM-1B、blaCTX-M-55;氨基糖苷类aac(3)-IId、aph(3’)-Ia、aph(3’’)-Ib、aph(6)-Id、rmtB、aac(6’)-Ib-cr、aadA2;粘菌素mcr-1;喹诺酮类qnrS2、aac(6’)-Ib-cr、oqxA、oqxB;磷霉素fosA3;大环内酯类mph(A);苯丙醇类catA1、floR、catB3;利福霉素ARR-3;磺胺类sul1、sul2、sul3、dfrA12、dfrA14;四环素类tet(A)。另外,含有mcr-1基因的质粒通过实验证实可发生接合转移。【结论】结果显示费格森埃希菌可能是重要耐药基因存储库,费格森埃希菌与大肠埃希菌要在抗药性流行病学中加以区分,深入研究其MIC频率分布、重要耐药基因mcr-1及ESBL等,保障临床检测的准确性。

[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-1 A, blaCTX-M-65, blaOXA-1, blaTEM-1 B, 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.