猪源大肠杆菌耐药性及超广谱β-内酰胺酶流行性分析

目的 对福建地区分离的猪源大场杆菌进行耐药性测定以及对ESBLs流行性进行分析,以期为临床合理用药科学提供依据。方法 采用琼脂稀释法测定373株菌大肠杆菌对12种抗菌药物的敏感性,并用PCR方法检测ESBLs耐药基因的携带情况以及分析CTX-M阳性菌的种系发育关系。结果 分离株对甲氧苄啶/磺胺甲噁唑、萘啶酸、氟苯尼考及氨苄西林耐药率较高,分别为93.8%、82.8%、73.7%和70.0%;对恩诺沙星、四环素、庆大霉素、多西环素、环丙沙星、卡那霉素、头孢噻呋和头孢噻肟的耐药率依次为54.4%、53.1%、52.0%、46.6%、44.0%、41.0%、35.9%和30.8%。在373株大肠杆菌中,共有122株菌携带有ESBLs耐药基因,检出率为32.7%,其中CTX-M、TEM及OXA的检出率分别是18.0%(67)、12.1%(45)和7.5%(28),其中CTX-M的阳性菌中以CTX-M-14最为流行,其次是CTX-M-65和CTX-M-55;其种系发育显示分离株主要分布在A群。结论 福建地区猪大肠杆菌对抗菌药表现出较强的耐药性,ESBLs在猪源大肠杆菌中广泛流行,CTX-M是其主要流行的基因型,并且多数菌以共生型大肠杆菌为主。

Antimicrobial resistance analysis and extended-spectrum-β-lactamaeses genes detection in Escherichia coli isolated from swine

The aim of this research was to study the prevalence of antimicrobial resistance and distribution of extended-spectrum-β-lactamaeses (ESBLs) genes of the Escherichia coli isolated from swine, and provided guidance for the rational use of antibiotics. A total of 373 isolates were tested for antimicrobial susceptibility to 12 antimicrobial agents by agar dilution method, screened for ESBLs genes and analysed phylogenetic group among the CTX-M positive isolates by PCR. Results showed strains were found high resistance rates to trimethoprim/sulfamethoxazole, nalidixic acid, florfenicol and ampicillin, with resistance rates of 93.8%, 82.8%, 73.7% and 70.0%, respectively. Strains had showed resistance to enrofloxacin, tetracycline, gentamicin, doxycycline, ciprofloxacin, kanamycin, ceftiofur and cefotaxime, and the resistance rates were 54.4%, 53.1%, 52.0%, 46.6%, 44.0%, 41.0%, 35.9% and 30.8% as follows. There were 32.7% (122/373) of the isolates carried ESBLs genes, including CTX-M (18.0%, 67), TEM (12.1%, 45) and OXA(7.5%, 28) genes, and the CTX-M-14 was the most predominant subtype during the encoding CTX-M isolates, then of CTX-M-65 and CTX-M-55. Phylogeny showed that the strains were mainly distributed in the A group. This research revealed that high rates of resistance to antimicrobial agents, and ESBLs was widely prevalent in Escherichia coli isolated from Fujian Province. The CTX-M was the most predominant gene among those strains, and the majority of them belonged to symbiotic Escherichia coli.