大肠埃希菌耐药性分析及生物被膜形成能力研究

目的 探讨医院产ESBLs大肠埃希菌(ECO)临床分离株的流行现状、耐药性及其生物被膜形成能力,为医院感染控制和临床诊疗感染性疾病提供依据.方法 采用法国生物梅里埃公司的VITEK-2 Compact全自动微生物分析仪对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菌株的生物被膜形成能力.结果 医院ECO检出前3位病区分别为普外病区、肾脏病区和呼吸病区；检出前3位标本分别为痰、尿和血液；466株ECO临床分离菌株中,产ESBLs菌株297株占63.73％,非产ESBLs菌株169株占36.27％；对＞3类抗菌药物耐药ECO 357株占76.61％,其中,产ESBLs菌株287株占61.59％,耐药率最高的为氨苄西林,其次为头孢唑林和头孢曲松；环丙沙星和左氧氟沙星的耐药率均＞60.0％；已出现耐亚胺培南ECO;对于临床常用的青霉素类、头孢菌素类、氟喹诺酮类、氨基糖苷类和单酰胺类抗菌药物,与非产ESBLs菌株相比,产ESBLs菌株的MIC值与耐药率显著升高；而对头霉素类、呋喃类、含酶抑制剂的哌拉西林/他唑巴坦和碳青霉烯类药物的敏感性产ESBLs组与非产ESBLs组比较差异无统计学意义；＞90.00％的ECO具有生物被膜形成能力,生物被膜形成量以中量为主,不同标本来源的菌株之间生物被膜形成能力差异无统计学意义.结论 医院ECO产ESBLs比例高,生物被膜形成能力强,呈现多药耐药的特征,医院应加强产ESBLs菌株的分子流行病学调查和感染控制,避免医院感染的暴发流行.

Antibiotic resistance and ability of biofilm formation of Escherichia coli strains

OBJECTIVE To approach the prevalence and drug resistance of extended β-lactamases(ESBLs)-producing Escherichia coli and its ability of biofilm formation,in order to provide guidance for clinical medication and control of nosocomial infections.METHODS E.coli identification and drug susceptibility testing were performed by using VITEK2 COMPACT of Biomerieux.The method of microtiter plate culture-crystal violet stain was used for quantitative analysis of biofilm formation.RESULTS The department of general surgery,department of nephrology and department of respiratory medicine were the first three departments that were with the highest detection rate of E.coli.The sputum,urine and blood were the first three clinical specimens from which E.coli strains were isolated;a total of 297(63.73%) strains of ESBLs-producing E.coli were isolated from 466 E.coli clinical strains,there were 169(36.27%) non-ESBLs-producing E.coli strains;there were 357 strains(76.61%) of E.coli resistant to more than three antibiotics,among which there were 287 strains(61.59%) of ESBLs-producing E.coli,the drug resistance rate was the highest to ampicillin,followed by cefazolin and ceftriaxone;the drug resistance rates to ciprofloxacin and levofloxacin were over 60.0%;imipenem-resistant E.coli strains have emerged;as compared with MIC of non-ESBLs-producing strains,the MIC of ESBLs-producing strains to commonly used antibiotics including penicillins,cephalosporins,fluoroquinolones,aminoglycosides and monobactams was increased significantly,and the drug resistance rate was significantly increased;the difference in the antibiotics susceptibility to cefotetan,nitrofurans,piperacillin/tazobactam and carbapenems between the ESBLs-producing strains and non-ESBLs-producing strains was not statistically significant;more than 90% of the clinical isolates of E.coli possessed the ability of forming the biofilm,and most isolates produced medium quantity