耐环丙沙星大肠埃希菌对氨基糖苷类药物的耐药性探讨

Drug resistance analysis of ciprofloxacin-resistant Escherichia coli to aminoglycosides

目的探讨本地区耐环丙沙星(CIP)大肠埃希菌临床分离株对氨基糖苷类药物的耐药表型与基因型的相关性。方法用纸片扩散法测定75株大肠埃希菌对CIP和6种氨基糖苷类药物的耐药率,PCR法检测6种氨基糖苷类修饰酶基因。结果 53株(70.67%)对CIP耐药。耐CIP菌株对庆大霉素、卡那霉素、链霉素、妥布霉素、奈替米星、阿米卡星的耐药率分别为:73.58%、64.15%、62.26%、50.94%、16.98%、13.21%;与非耐CIP菌株比较,庆大霉素、卡那霉素、妥布霉素耐药率的差异均有统计学意义(P<0.05),多重耐药表型的差异同样具有统计学意义(P<0.05),耐CIP菌株aac(3)-II和aac(6′)-I的检出率为主(56.60%、41.51%);与非耐CIP菌株比较aac(6′)-I检出率的差异有统计学意义(P<0.05)。结论耐CIP菌株多表现为同时对多种氨基糖苷类药物耐药,提示耐CIP大肠埃希菌对氨基糖苷类药物的耐药与氨基糖苷类修饰酶存在一定相关性,尤以AAC(6′)-I为明显。

The objective of this study was to detect the relativity of drug resistance phenotypes and genotypes about ciprofloxacin-resistant （CIP-resistant） Escherichia coli （E.coli） to aminoglycosides for clinic isolates. The antibiotic susceptibility tests of 75 E.coli strains to ciprofloxacin （CIP） and 6 kinds of aminoglycosides drugs were performed by Kirby-Bauer disk diffusion method. Then 6 kinds of aminoglycoside-modifying enzyme genes in these strains were amplified by PCR and their products were sequenced. 53 strains （70.67%） were resistant to CIP and the resistant rates of CIP-resistant strains to Gentamicin,Kanamycin,Streptomycin,Tobramicin,Netilmicin and Amikacin were 73.58%,64.15%,62.26%,50.94%,16.98% and 13.21%,respectively. The resistant rates of CIP-resistant strains to Gentamicin,Kanamycin and Tobramicin were higher than that of non-CIP-resistant strains. CIP-resistant strains were multidrug resistant to aminoglycosides. The rates of CIP-resistant strains to aac（3）-II and aac（6＇）-I were 56.60% and 43.40% respectively,and the rates of CIP-resistant strains to aac（6＇）-I was higher than that of non-CIP-resistant strains. CIP-resistant E.coli strains were multidrug resistant to aminoglycosides and the resistance of CIP-resistant E.coli strains to aminoglycosides is associated with aminoglycoside-modifying enzymes,especially aac （6＇）-I.