常见肠杆菌科细菌临床株aac(6＇)-Ib-cr基因的流行现状和耐药特征

摘要

目的 研究氨基糖苷乙酰胺转移酶基因的突变形式aac(6’) -Ib -cr在肺炎克雷伯菌和大肠埃希菌临床株中的分布状况；分析携带该基因菌株对环丙沙星、氨基糖苷类和头孢菌素类的耐药特征.方法 利用多聚酶链式反应检测肺炎克雷伯菌和大肠埃希菌临床分离株中aac(6’)-Ib基因携带情况,采用BtsC I酶切消化,经DNA测序确认aac(6 ’)-Ib-cr基因；统计分析aac(6’) -Ib-cr基因与环丙沙星、头孢菌素类和氨基糖苷类耐药性关系.结果 aac(6’)-Ib-cr基因在肺炎克雷伯菌和大肠埃希菌的检出率分别为12.6％ (30/238)和18.8％ (13/69)；aac(6 ’)-Ib-cr阳性株与阴性株对环丙沙星的耐药率分别为72.1％ (31/43)和48.1％(127/264),差异有统计学意义(X2=8.52,P＜0.05).肺炎克雷伯菌aac(6’)-Ib-cr基因阳性株对阿米卡星的耐药率高于aac(6’) -Ib-cr基因阴性株(X2=4.25,P＜0.05).aac(6’)- Ib-cr基因阳性株和阴性株对庆大霉素的耐药率、常用的头孢菌素类的耐药率和多重耐药率均较高,无统计学差异.结论 本地区肺炎克雷伯菌和大肠埃希菌临床分离株中,aac(6’) -Ib-cr基因均有检出；aac(6’)-Ib-cr基因阳性株对环丙沙星耐药率明显高于阴性株,肺炎克雷伯菌中aac(6’)-Ib-cr基因阳性株对阿米卡星的耐药率明显高于阴性株,具有统计学意义.aac(6’) - Ib-cr基因阳性株和阴性株对常用头孢菌素类的耐药率和多重耐药率均较高,无统计学意义.%Objective To investigate the prevalence of aac (6')-Ib-cr gene in clinical isolates of Klebsiella pneumoniae and Escherichia coli,and analyze the drug-resitant charactcristios of positive aac ( 6' ) - ib- cr isolates of fluoroquinolones,aminoglyeosides and cephalosporins.Methods aac ( 6' ) -Ib gene were detected by PCR.Positive PCR products of aac(6')-Ib were digested with BtsCI and sequencing to identify aac(6')-Ib-cr; analyze the resistance to fluoroquinolones,aminoglycosides and cephalosporins in isolates containig aac( 6 ' ) -Ib-cr gene with statistical methods.Results aac( 6' ) -Ib -cr gene was detected in 12.6 ％ ( 3 0 / 2 3 8 ) of Klebsiella pneumoniae isolates and 18.8 ％ ( 1 3 / 6 9 ) of Escherichia coli isolates; the resistance rates of ciprofloxacin in positive and negative aac (6')-Ib-cr isolates were 72.1％ (31/43) and 48.1％ (127/264),the difference was statistically significant (x2 =8.52,P ＜ 0.05 ).The resistance rate of amikacin in positive aac ( 6' ) -Ib-cr of Klebsiella pneumoniae isolates was significantly higher than negative isolates(x2 =4.25,P ＜ 0.05 ).All the isolates displayed a high resistant rate to gentamicin and cephalosporins which else showed multidrug resistance,regardless the carrying of aac (6')-Ib-cr gene,which showed no significant difference.Conclusion In the region,aac (6')-Ib-cr gene was both detected in Klebsiella pneumoniae and Escherichia coli clinical isolates; The resistance rate to ciprofloxacin in positive aac (6')-Ib-cr isolates was significantly higher than negative isolates,so did to amikacin in Klebsiella pneumonia isolates,which had statistical significance,the resistance rate and the multiple resistance rate of common used cephalosporins in whether positive or negative aac(6')-Ib-cr isolates were high,which has no statistically significant.