皖南地区大肠埃希菌与克雷伯菌属ESBLs表型及基因型的检测

Detection of Extended-spectrum Beta-lactamases and Genotypes in Escherichia coli and Klebsiella isolates in Wannan Area

目的研究安徽省南部地区3所医院临床分离株中大肠埃希菌和克雷伯菌属超广谱β-内酰胺酶(ESBLs)的产生情况、耐药性及其基因型分布。方法平皿琼脂对倍稀释法测定79株大肠埃希菌和克雷伯菌属对13种抗菌药物的耐药性;采用2005年CLSI推荐方法对收集菌株进行ESBLs确证试验;用PCR方法对产ESBLs菌株使用8对引物进行β-内酰胺酶基因的扩增,扩增产物回收纯化后测序。结果皖南地区3所医院临床分离大肠埃希菌和克雷伯菌属中产ESBLs株的检出率分别为61.5%和45.0%,ESBLs产生株对CRO、CTX、CAZ、CIP、LEV的耐药率分别为81.0%、81.0%、47.6%、71.4%、50.0%,对亚胺培南和美罗培南100%敏感;PCR及测序结果显示产ESBLs菌株中,大肠埃希菌CTX-M1型12株(50.0%),CTX-M13型11株(45.8%),OXA1型11株(45.8%),TEM型19株(79.2%);克雷伯菌属CTX-M1型4株(22.2%),CTX-M13型10株(55.6%),OXA1型、OXA2型、TOHO1型各1株,TEM型9株(50.0%)。结论皖南地区3所医院临床分离大肠埃希菌和克雷伯菌属中产ESBLs株的检出率和对头孢菌素类及喹诺酮类的耐药率均达到相当高水平,应加强对产ESBLs株的临床监测,同时要加强临床对抗菌药物的合理使用。

OBJECTIVE To investigate the ESBLs-producing isolates and their resistance and genotypes in Escherichia coli and Klebsiella in three hospitals of Wannan area. METHODS The MIC of 13 antimicrobials against 79 strains of E. coli and Klebsiella were determined by 2-fold agar dilution method. The confirmation test was used to detect ESBLs-producing strains according to CLSI 2005. PCR method was used to amplify beta-lactamases of ESBLs-producing isolates by 8 premiers, PCR products were purified and then sequencing was performed. RESULTS The ESBLs-producing rates in E. coli and Klebsiella in three hospitals of Wannan area were 61.5 % and 45.0%, respectively. The resistance rates to CRO, CTX, CAZ, CIP and LEV of ESBLs-producing strains were 81.0%, 81.0%, 47. 6%, 71.4% and 50. 0%, respectively, all isolates were susceptible to meropenem and imipenem. PCR indicated that CTX-Mt, CTX-M13, TEM and OXA1 types of beta-lactamases were the four major genotypes of the three hospitals in Wannan area. CONCLUSIONS The isolation rates of ESBLs-producing E. coli and Klebsiella as well as their resistance rates to cephalosporins and quinolones in the three hospitals in Wannan area are quite high. Monitoring ESBLs-producing isolates should be strengthened in clinic and laboratory.