ERIC-PCR技术在鲍曼不动杆菌基因分型中的应用评估

Application evaluation of ERIC-PCR on genotyping of Acinetobacter baumannii

目的了解仁济医院鲍曼不动杆菌的基因同源性,验证肠杆菌科基因间重复序列(ERIC)-聚合酶链反应(PCR)在鲍曼不动杆菌基因分型中的实用性。方法采用琼脂稀释法检测临床分离的81株鲍曼不动杆菌对临床常用抗菌药物的最低抑菌浓度(MIC);采用ERIC-PCR对81株鲍曼不动杆菌进行基因分型;使用脉冲场凝胶电泳(PFGE)技术对其中的43株耐亚胺培南鲍曼不动杆菌进一步分型,以PFGE分型为参考标准,验证ERIC-PCR在基因分型中的实用性。结果 81株鲍曼不动杆菌对临床常用的13种抗菌药物普遍耐药,只对米诺环素耐药率最低,为30.9%,其次是亚胺培南,为53.1%,对其他抗菌药物的耐药率均>60%。81株鲍曼不动杆菌ERIC-PCR分型主要为A、B、C、D、E、F 6型,其中A、B、C型为主要的流行株。43株耐亚胺培南鲍曼不动杆菌分型为A型41株(A1型29株,A2型12株)、B型1株、C型1株。PFGE分型将其分为5型,A型34株(A1型31株,A2型3株),B型6株,C、D、E分型各1株。结论仁济医院鲍曼不动杆菌存在克隆播散,且主要为耐亚胺培南鲍曼不动杆菌。ERIC-PCR分辨力较强,结果可靠,与PFGE结果具有一定的相关性,是一种简便、快捷的基因分型技术。

Objective To investigate the gene homology of Acinetobacter baumannii clinical isolates in Renji Hospital and to demonstrate the role of enterobacterial repetitive intergenic consensus （ERIC） -polymerase chain reaction （PCR） on genotyping of Acinetobacter baumannii. Methods The minimum inhibitory concentrations （MIC） of common clinical antibiotics against 81 isolates of Acinetobaeter baumannii were determined by agar dilution method. ERIC-PCR was used to type 81 isolates of Acinetobaeter baumannii. Pulsed-field gel electrophoresis （PFGE） as reference standard was used to further type 43 imipenem-resistant Acinetobaeter baumannii. The practicability of ERIC-PCR was verified. Results The 81 isolates of Acinetobacter baumannii were commonly resistant to 13 antibiotics. The lowest resistant rate was 30.9% for polymyxin, the second was 53.1% for imipenem, and the others were all 〉60%. The 81 isolates of Acinetobacter baumannii were classified into 6 types by ERIC-PCR, named genotype A, B, C, D, E and F. There mainly were A, B and C genotypes. The 43 imipenem-resistant Aeinetobaeter baumannii belonged to 3 genotypes, including genotype A had 41 isolates （29 isolates of type A1 and 12 isolates of type A2） , genotype B had 1 isolate, and genotype C had 1 isolate. There mainly were 5 PFGE pulsotypes for the 43 isolates, pulsotype A had 34 isolates （31 isolates of type A1 and 3 isolates of type A2） , pulsotype B had 6 isolates, and C, D and E types had 1 isolate for each. Conclusions There has been clonal spread of Acinetobacter baumannii among patients in the hospital, which mainly were imipenem-resistant Acinetobaeter baumannii. The ERIC-PCR is a useful and expeditious method for genotyping of Acinetobacter baumannii, and the results are correlated with those of PFGE.