食源性沙门氏菌第Ⅰ类整合子检测及其耐药基因盒分析

Detection of class Ⅰ integron from foodborne salmonella and analysis on the drug resistance gene cassettes

目的:了解食源性沙门氏菌的耐药性、Ⅰ类整合子分布及其耐药基因盒的结构序列,为Ⅰ类整合子的分子进化提供理论基础。方法:采用K-B纸片法检测食源性沙门氏菌对14种抗生素的敏感性;利用聚合酶链式反应(PCR)扩增整合酶基因intI1检测食源性沙门氏菌中Ⅰ类整合子携带率及可变区耐药基因盒。结果:食源性沙门氏菌对β-内酰胺类、氨基糖苷类、喹诺酮类和磺胺类的最高耐药率分别为18.75%、12.5%、6.25%和25%。59.4%(19/32)的食源性沙门氏菌检测出第Ⅰ类整合子。PCR扩增Ⅰ类整合子耐药基因盒,扩增产物大小为1009和1664bp,携带aadA5、dfr17和aadA2耐药基因,可分别介导对氨基糖苷类抗生素壮观霉素、链霉素和磺胺类药物甲氧苄氨嘧啶的耐药。结论:食源性沙门氏菌中也检测到较高的耐药率及整合子携带率,提示我们应该从基因水平上对食源性致病菌耐药及其传播进行监测。

Objective：To investigate the drug resistance,the distribution of class ] integron and drug resistance gene cassette of foodborne salmonella. Methods= K-B assay was applied to measure the drug resistance of foodborne salmonella isolated against fourteen antibiotics.The class ]r integron and drug resistance gene cassette were detected by PCR sequencing of amplification products, Results= The highest drug resistance rate to J3-1actams,aminoglycosides, quinonones and sulfa in foodborne salmonella was 18.75%, 12.5% ,6.25% and 25%. 59.4% （19/32）of foodborne salmonella were positive for class I integron.The product by PCR amplifying of class I integron was lO09bp and 1664bp. ln the drug resistance cassettes of variable regions of class I integrons there were 3 types drug resistance genes, including aadAS, dfrl7 and aadA2, which induced the resistance to aminoglycosides antibiotics spectinomycin, streptomycin and sulfonamides drugs trimethoprim. Conclusion. High multidrug resistance and class I integron carrying had been identified among the foodborne salmonella.The result stressed the need for continued surveillance of foodborne antibiotic resistance bacteria in the molecular level.