鸡志贺氏菌产超广谱β内酰胺酶(ESBLs)的分子进化  

Molecular Evolution of the Extended Spectrum β-lactamase (ESBLs) Produced by the Shigella Isolated from the Fowl

作　　者：胡功政[1] 孙亚伟[1] 陈红英[1] 司红彬[1] 苑丽[1] 邓立新[1] 莫娟[1] 李胜利[1] 

机构地区：[1]河南农业大学牧医工程学院,郑州450002

出　　处：《中国农业科学》2008年第2期593-598,共6页Scientia Agricultura Sinica

基　　金：国家自然科学基金资助项目(30471307)

摘　　要：【目的】检测鸡志贺氏菌分离株和诱导株所产ESBLs的基因型,探讨其产酶耐药的分子进化机制。【方法】对1株诱导和5株临床分离产ESBLs细菌分别用TEM、SHV、CTX-M3种通用引物进行PCR扩增、基因克隆及测序分析,确定鸡福氏志贺氏菌ESBLs的基因型和基因亚型。【结果】5株临床福氏志贺氏菌质粒上具有相同的TEM序列和相同的SHV序列,TEM型序列与AY903309(TEM-116)序列相比发生了2个位点基因突变即G157A、C409T,其中409位点碱基突变为沉默突变,157位点碱基突变导致相应氨基酸序列53位发生突变Gly53Ser,此氨基酸突变为新的突变位点,所以该TEM型ESBLs是一种新的TEM亚型,暂命名为TEM-1V型;SHV型与AY826418(SHV-12)序列完全相同,为SHV-12型。头孢噻呋诱导标准福氏志贺氏菌,诱导10代时产生了TEM-1型β-内酰胺酶,诱导50代时产生了TEM-1V型ESBLs。【结论】临床分离鸡福氏志贺氏菌ESBLs的基因型为TEM-1V型和SHV-12型,鸡福氏志贺氏菌TEM-1V型ESBLs是由TEM-1型β内酰胺酶直接进化而来。【Objective】 The genotypes of ESBLs produced by Shigella flexneri were detected to elucidate the molecular evolution mechanism of the ESBLs production. 【Method】 Five clinically isolated and one induced Shigella flexneri were amplified by PCR using the primers of TEM, SHV and CTX-M, respectively, their PCR products were cloned and then the cloned fragments were sequenced. The nucleotide sequence obtained were analyzed using DNASTAR software. The search for homologous sequences was done in the GenBank database using FAST software. 【Result】 The same TEM- type and SHV- type sequences were noticed in the plasmids of the five Shigella flexneri isolates. The sequence of the TEM-type was characterized by two nucleotide mutations （G157A, C409T） compared with that of AY903309 （TEM-116）. The mutation of nucleotide 409 was aslient mutation. The mutation of nucleotide 157 led to the mutation of amino acid （Gly53Ser）. Because the mutation didn＇t appear in the published ESBLs sequences. Therefore, the detected TEM-type was a new genotype, named TEM-1V type. The sequence of SHV-type was the same as that of the AY826418 （SHV-12）. The standard Shigella flexneri produced TEM-1 type β-lactamase and TEM-1V type ESBLs, respectively, when it was induced to the tenth and fifth times by Ceftiofur. 【Conclusion】 The isolated Shigella flexneri harboreds TEM-1V type and SHV-12 type ESBLs and the produced TEM-1V type ESBLs evoluted directly from TEM-1 type β-lactamase.

关 键 词：福氏志贺氏菌 ESBLS 基因型 

分 类 号：S852.61[农业科学—基础兽医学]