尿液分离大肠埃希菌株耐药性及生物被膜形成分析

摘要

目的 探讨我院尿路感染患者产ESBLs大肠埃希菌株(ECO)检出率、对常用抗菌药物的耐药性及生物被膜形成能力.方法 采用法国生物梅里埃公司的VITEK2-COMPACT全自动微生物分析仪,对2010年10月~2011年12月临床送检的尿液标本分离ECO菌株进行鉴定和药物敏感性分析,采用结晶紫半定量方法检测其生物被膜形成能力.结果 115株ECO临床尿液分离菌株中,产ESBLs菌株68株,占59.13%;ESBLs阴性菌株47株,占40.87%.对3种以上不同种类抗菌药物耐药ECO 82株,占71.30%,其中,产ESBLs菌株64株,占总菌株数的55.65%,占产ESBLs菌株数的94.12%.耐药率最高的为氨苄西林(88.70%),其次为头孢唑啉(65.22%);环丙沙星和左氧氟沙星的耐药率均在60%以上.对于临床常用的青霉素类、三代头孢菌素类、氟喹诺酮类、氨基糖甙类的妥布霉素和庆大霉素、单酰胺类、磺胺类抗菌药物,与ESBLs阴性菌株相比,产ESBLs菌株的MIC值显著升高,耐药率显著升高(P＜0.05或P＜0.01);而对头霉素类、四代头孢菌素、呋喃类、氨基糖甙类的阿米卡星、含酶抑制剂的哌拉西林/他唑巴坦和碳青霉烯类抗菌药物的敏感性,ESBLs阳性组与ESBLs阴性组比较无统计学差异.98.26%的ECO临床尿液分离株具有生物被膜形成能力,生物被膜形成量以中量和大量为主.结论 我院尿液分离ECO菌株产ESBLs比例高,生物被膜形成能力强,呈现多药耐药的特征.%Objective To discuss the detection rate of escherichia coli ( ECO) strains isolated from urine extended β-actamases ( ESBLs) in patients with urinary tract infection , their drug resistance, and their ability of biofilm formation. Methods VITEK2-COMPACT microbe analysator was used to identify the ECO strains isolated from urine specimens which were clinically collected from October 2010 to December 2011 and determined their drug susceptibility. Crystal violet semiquantitative method was used to detect the ability of biofilm formation. Results Among the 115 strains of ECO isolated from urine specimens , there were 68 strains (59. 13% ) producing ESBLs and 47 strains(40. 87% )which did not produce ESBLs. Eighty two strains of ECO(71. 30% )were resistant to more than three kinds of antibiotics. Among these strains ,64 ones produced ESBLs which accouted for 55. 65% of the total number of stains and 94.12% of the strains producing ESBLs. The resistant rate to the antibiotics below was the highest : ampicillin (88. 70% ) and cefazolin(65. 22% ). Both resistant rates to ciprofloxacin and levofloxacin were more than 60%. For commonly used penicillins, Ⅲ generation of cephalosporins , fluoroquinolones , tobramycin, gentamicin, monobactams, and sulfanilamide antibiotics ,the MIC value and the drug resistant rate of the strains producing ESBLs significantly increased compared with those of the strains not producing ESBLs (P<0.05 or P<0.01). There was no significant difference in the susceptibility between the strains producing and not producing ESBLs,as to the antibiotics such as cefotetan ,cefepime,nitrofurans,amikacin,piperacillin/tazobactam,and carbapenems. 98. 26% of the isolated strains had the ability of biofilm formation . Conclusion The proportion of strains producing ESBLs is high in the isolatied ECO from urine specimens ,and they have strong ability of biofilm formation. They have the characteristic of multi-drug resistance.