羊源大肠杆菌对氨基糖苷类药物耐药表型及耐药基因的检测

Analysis of aminoglycoside antibiotics resistance phenotype and drug resistance gene of E.coli from sheep

(无菌采集绵羊粪便,采用细菌常规分离鉴定结合16S rRNA PCR扩增的方法分离鉴定大肠杆菌,应用K-B药敏纸片的方法研究分离的大肠杆菌耐药表型及PCR方法检测全部菌株氨基糖苷类耐药基因AadB、AadA1、Aac(3′)-Ⅱ、Aac(6′)-Ⅰb和Aph(3′)-Ⅰ的携带情况。结果显示,共分离100株羊肠道正常菌群大肠杆菌,分离株对链霉素的耐药率最高,为24%,其次是新霉素、丁胺卡那、庆大霉素和卡那霉素,分别为21%,14%,13%,7%;AadA1和Aph(3′)-Ⅰ耐药基因的检出率分别为98%和89%,未检测到AadB、Aac(3′)-Ⅱ和Aac(6′)-Ⅰb基因。结果表明,新疆石河子市羊肠道正常菌群大肠杆菌对氨基糖苷类抗生素具有较为广泛的耐药性,耐药基因主要以AadA1和Aph(3′)-Ⅰ为主,本试验为羊致病性大肠杆菌耐药机理的进一步研究提供有用数据。

In order to study the drug-resistant phenotype and gene carrying of Escherichia coli(E.coli)from normal flora of sheep intestinal tract in Shihezi City,Xinjiang,sheep feces were collected aseptically.E.coli was isolated and identified by routine bacterial isolation and identification combined with 16 S rRNA PCR amplification.The aminoglycoside antibiotics resistant phenotype of E.coli was studied by K-B and resistance gene(AadB,AadA1,Aac(3′)-Ⅱ,Aac(6′)-Ib and Aph(3′)-Ⅰ)were detected by PCR.The results showed that 100 E.coli from normal intestinal flora were isolated,with to streptomycin 24%the highest resistance rate,followed by neomycin,amikacin,gentamicin and kana,they were 21%,14%,13%and 7%respectively.The detection rates of AadA1 and Aph(3′)-Ⅰgenes in 100 non-pathogenic sheep-derived E.coli were 98%and 89%respectively,and these strains did not carry AadB,Aac(3′)-Ⅱand Aac(6′)-Ib genes.E.coli from normal intestinal flora of sheep in Shihezi,Xinjiang had extensive resistance to aminoglycoside antibiotics.The main resistance genes were AadA1 and Aph(3′)-Ⅰ.The results provide useful data for further study on the mechanism of drug resistance of sheep pathogenic E.coli.