目的 了解分离自临床标本的耐碳青霉烯类抗生素产气肠杆菌的耐药机制.方法 对临床分离到非重复的16株厄他培南耐药,及亚胺培南耐药或敏感性减低的产气肠杆菌采用改良Hodge试验和聚合酶链反应(PCR)检测KPC酶及其KPC酶基因,并采用转移接合试验对KPC酶基因阳性的菌株进行转移接合.结果 对16株产气肠杆菌的改良Hodge试验和KPC-2酶基因扩增试验结果均呈阳性,阳性菌株均可发生转移接合.结论 16株耐碳青霉烯类抗生素产气肠杆菌的主要耐药机制是产KPC-2碳青霉烯酶.此KPC-2基因可以通过质粒介导水平传播.临床医学工作者应予以高度重视,预防和控制此类菌株的播散.%Objective To investigate the resistance mechanism of carbapenem-resistant Enierobacteraerogenes. Methods Sixteen nonduplieate strains of ertapenem-resistant and imipenem-resistant (or intermediate) E. Aerogenes were isolated from patients. Isolates were screened for KPC producing phenotype by modified Hodge test. PCR amplification was used to analyze the existence of the KPC-2 gene in the 16 isolates. Transmission mechanism of the KPC-positive strains was studied by the conjugation experiment to reveal the transferability of plasmid related to carbapenem resistance. Results Modified Hodge test showed that all the 16 strains of E. Aerogenes produced carbapenemase. The carbapenem-hydrolyzing beta-lactamase genet KPC-2, was identified in all the 16 isolates by PCR and sequence analysis. Conjugation tests indicated that KPC-2 gene in the 16 isolates was transferred to recipient E. Coli strains by plasmid. Conclusions Production of plasmid-mediated carbapenem-hydrolyzing beta-lactamase KPC-2 is the main mechanism of the 16 Enterobacter aerogenes resistant to carbapenems. The KPC-2 gene of the 16 isolates can be horizontally transmitted by plasmid. It has important implications for controlling the transmission of such carbapenem-resistant strains.
展开▼
