临床分离的肺炎克雷伯菌和大肠埃希菌中超广谱β-内酰胺酶的检测

目的：检测临床分离的临床分离的肺炎克雷伯菌和大肠埃希菌中产超广谱β-内酰胺酶（ESBL）菌株的发生率、耐药性、流行性以及酶的基因型别。方法：采用双纸片法、琼脂稀释法、PCR、脉冲场电泳对1999年复旦大学附属华山医院临床分离的559株肺克雷伯菌和427株大肠埃希菌进行检测。结果：肺炎克雷伯菌和大肠埃希菌中产ESBL菌株的发生率分别为51％和23.6％,产ESBL菌株主要分布于ICU和神经外科病房,对大多数的β-内酰胺酶和非β-内酰胺类抗菌药物耐药;PFGE显示,产ESBL菌株（尤其是产ESBL肺炎克雷伯菌株）在ICU病房中存在同一菌株的克隆传播;PCR检测显示TEM型是最为常见的β-内酰胺酶型别,CTX-M型ESBL亦较为普遍。结论：产ESBL菌株在临床分离的肺炎克雷伯菌和大肠埃希菌中较为普遍,而且为多重耐药菌株,在医院内中存在流行与传播。

Extended-spectrum beta-lactamase in Klebsiella pneumoniae and Escherichia coli isolates

OBJECTIVE: To investigate the prevalence, drug resistance, gene typing, and epidemicity of extended-spectrum beta-lactamases (ESBL) Klebsiella pneumoniae and Escherichia coli isolates. METHODS: 559 strains of K. pneumoniae and 427 strains of E.coli were isolated form Huanshan Hospital from 1 January to 31 December 1999. The ESBL-producing strains were detected by double disc test and confirmed by minimal inhibitory concentration (MIC). The MIC of ESBL-producing strains was detected by agar dilution test. The beta-lactamase genes were detected by PCR. DNA fingerprinting was made by pulsed-field gel electrophoresis (PFGE). RESULTS: The incidence of ESBL-producing strains was 51% among the isolated K. pneumoniae (285/559) and 23.6% among the isolated E. coli (101/427), most of which were collected from the patients in the intensive care unit and neurosurgical ward. 63.5% of the ESBL-producing K. pneumoniae strains were collected from sputum specimens, and 64.3% of the ESBL-producing E. coli strains were collected from the urine specimens. Most ESBL-producing strains were resistant to most beta-lactam antibiotics, including the third-generation cephalosporins, and non- beta-lactam antimicrobial drugs, such as fluoroquinolones, aminoglycosides, tetracycline, and chloramphenicol. Most of the ESBL-producing strains were susceptible to imipenam, cefmetazole, and beta-lactam antibiotic/clavulanic acid. TEM type beta-lactamase was the main type among those EBSL-producing strains, followed by SHV type and CTX-M type. Some ESBL-producing E. coli and most ESBL-producing K. pneumoniae produced more than one type of beta-lactamase. CONCLUSION: ESBL-producing strains are common among hospital strains of E. coli and K. pneumoniae. Most of them are multidrug resistant. Prevalence and transmission of these strains exist in hospital.