一种新型β内酰胺酶CTX-M-38的发现

CTX-M-38,a novel beta-lactamase produced by Klebsiella pneumoniae

目的了解CTX-M型ESBLs在深圳市人民医院临床分离肺炎克雷伯菌的分布。方法采用3组PCR引物分别扩增产ESBLs菌株的CTX-M基因,应用ABI自动荧光测序仪对PCR扩增产物进行测序。结果64株产ESBL肺炎克雷伯菌中,PCR阳性41株(64.1%),基因型分别为CTX-M-3(4株)、CTX-M-9(2株)、CTX-M-13(3株)、CTX-M-14(28株)和CTX-M-3合并CTX-M-14(2株)。在另外2株菌中发现1种新的CTX-M型酶,经美国Lahey临床医学中心专家确认并被命名为CTX-M-38,GenBank登录号AY822595。结论我院临床分离的肺炎克雷伯菌产CTX-M型ESBLs检出率较高,其中以CTX-M-14型为最常见,CTX-M-38是一种新基因型ESBL。

Objective To understand the distribution of CTX-M type ESBL in Klebsiella pneumoniae isolates from Shenzhen People＇s Hospital. Methods PCR and DNA sequencing were carried out to identify CTX-M genes. Results Among 64 ESBL-producing isolates, 41 were found carrying CTX-M genes, including CTX-M-3 （4 isolates）, CTX-M-9 （2 isolates）, CTX-M-13 （3 isolates）, CTX-M-14 （28 isolates）, and both CTX-M-3 and CTX-M-14 （2 isolates）. In addition, a novel CTX-M gene was found in another 2 isolates. Deduced amino acid sequence of the new gene differed from CTX-M-9 at two amino acid： Set220→ Arg and Ala231→Val, It was named as CTX M-38. GenBank accession No. AY822595. Conclusions CTX-Mq4 type is the major ESBLs of K. pneumoniae isolates in this hospital. CTX-M-38 is a novel β-lactamase.