肺炎克雷伯菌ESBLs及AmpC酶的基因分布检测与耐药特性的相关性研究

目的研究肺炎克雷伯菌ESBLs及AmpC酶的基因分布与耐药特性的相关性。方法收集2008年1月至2013年12月临床分离的100株肺炎克雷伯菌,采用K-B法进行体外药敏试验,采用ESBLs确证试验和AmpC三维试验确定产酶表型,采用聚合酶链式反应进行ESBLs酶及AmpC酶基因的检测。结果60株检测出ESBLs酶,其中60株内检出ESBLs基因阳性56株,主要为SHV型基因;检出AmpC酶的检测6株,主要为DHA型基因。其中两种基因同时阳性者1株。除哌拉西林/他唑巴坦,单产AmpC酶、ESBLs及两种基因同时阳性菌（SSBLs）对其他17种常用抗生素的耐药率均高于不产酶菌株。结论医院肺炎克雷伯菌的主要耐药机制为ESBLs酶及AmpC酶基因。ESBLs耐药基因检出率高,ESBLs阳性株耐药率明显高于ESBLs基因阴性株。

The correlation of ESBLs and AmpC enzyme gene distribution with drug resistance of Klebsiella pneumoniae

Objective To investigate the correlation between the gene distribution of ESBLs and AmpC and the drug resistance of Klebsiella pneumonia. Methods 100 strains were collected between January 2008 and December2013. All the strains were tested by K-B method for drug resistance. The phenotypes of ESBLs and AmpC were detected by ESBLs confirmatory test and AmpC-three-dimensional test,respectively. PCR and DNA sequencing were undertaken to detect ESBLs and AmpC genes. Results 60 strains of ESBLs producers were identified,mainly of the SHV type gene; 6 strains were detected as AmpC,mainly of the DHA type gene; 1 strain had both ESBLs and AmpC genes. In addition to piperacillin /tazobactam,the strains with AmpC,ESBLs or with both genes（ SSBLs）were more resistant to the other 17 antibiotics than those of non enzyme producing strains. Conclusion The main mechanism of drug resistance of nosocomial Klebsiella pneumonia is ESBLs enzyme and AmpC enzyme genes. The detection rate of resistant ESBLs gene is high,and the resistance rate of ESBLs positive strains is significantly higher than that of ESBLs negative strains.