重症监护病房铜绿假单胞菌医院获得性感染暴发的流行病学调查

目的对重症监护病房(ICU)铜绿假单胞菌医院获得性感染的暴发进行流行病学调查,并对其同源性进行分析。方法收集微生物和临床资料,评估铜绿假单胞菌感染率的变化。收集ICU环境和ICU医护人员的标本,监测可能的环境传染源。用K-B法对分离的细菌进行耐药性监测,用脉冲场凝胶电泳(PFGE)联合限制性内切酶法,对铜绿假单胞菌进行同源性分析。结果ICU患者的铜绿假单胞菌感染率由非暴发期的18·0%上升到暴发期(2004年5月~7月)的40·0%(P=0·000;OR值3·037;95%可信区间1·672,5·516)。随机选取从不同ICU患者分离的20株铜绿假单胞菌进行PFGE分型,共获得6种PFGE分型,12株为A型,同源性完全相同,其中11株分离自暴发期,该克隆株对青霉素类、头孢菌素类和碳青霉烯类等抗菌药物耐药。采取防治措施后,2004年8月ICU铜绿假单胞菌的感染率降至基线水平(15·4%)。结论铜绿假单胞菌可发生克隆株在ICU患者的交叉感染,引起医院获得性感染的暴发流行,呈多药耐药,应控制该菌在医院内的传播。

An outbreak of panantibiotic resistant Pseudomonas aeruginosa nosocomial infection in an intensive care unit in China

Objective To investigate an outbreak of panantibiotic resistant Pseudomonas aeruginosa nosocomial infection in an intensive care unit(ICU) in China.Methods Microbiological results and medical records were reviewed and the incidence of infection with Pseudomonas aeruginosa was assessed from Mar 2003 to Feb 2005.During an outbreak from May to July 2004,the environment and the hands of health care workers in ICU were sampled to reveal the possible environmental reservoirs.The chromosomal DNA genotyping of the selected isolates was analyzed for clonality by pulsed-field gel electrophoresis.Results The incidence rate of infection with Pseudomonas aeruginosa from ICU increased from 18.0 percent at base line to 40.0 percent during the outbreak(P=0.000,relative risk,3.037,95 percent confidence interval,1.672 to 5.516).Pulsed-field gel electrophoresis showed that 12 patients had the same clone of Pseudomonas aeruginosa.Among of 12 Pseudomonas aeruginosa, 11 were isolated during the outbreak.Furthermore the 12 isolates had the similar antibiogram which were resistant to penicillins,cephalosporins and carbapenems.The incidence of infection declined to 15.4 percent in Aug 2004 after the control measurements were implemented.Conclusions Pseudomonas aeruginosa is the most common pathogen of nosocomial infection.Furthermore the clonal spread of the panantibiotic resistant strain can cause nosocomial outbreak.Effective and cautious strategies must be determined to prevent the disastrous event.