产超广谱β内酰胺酶大肠埃希菌中SHV型β内酰胺酶的分子生物学研究

The molecular biological study of SHV β-lactamases in clinical isolates of ESBLs-producing Escherichia coli

目的 :了解复旦大学附属华山医院临床分离产超广谱 β内酰胺酶 (ESBLs)大肠埃希菌中SHV型 β内酰胺酶的分布、流行情况以及分子生物学特点。方法 :用SHV型 β内酰胺酶基因的通用引物进行聚合酶链反应 (PCR)检测 ;编码框以外设计引物、PCR扩增SHV型 β内酰胺酶全编码基因并进行克隆表达、序列分析 ;对产SHV型 β内酰胺酶的菌株进行脉冲场凝胶电泳 (PFGE)检测。结果 :5 8株产ESBLs大肠埃希菌中 ,只有 3株细菌产生SHV型 β内酰胺酶 (5 .2 % ) ,其中 1株产生SHV 1 1(非ESBLs) ,另 2株产生SHV 1 2 (ESBLs) ;3株产SHV型 β内酰胺酶菌株的PFGE谱型不同。 结论 :临床分离产ESBLs大肠埃希菌中 ,SHV型 β内酰胺酶的基因型为SHV 1 1和SHV 1 2 ,SHV型ESBLs不是主要的ESBLs型别。未发现产SHV型

Objective: To investigate the prevalence and molecular biological characteristics of SHV β lactamases in strains of ESBL producing Escherichia coli isolated from Huashan Hospital. Methods:The partial bla SHV of ESBLs producer was amplified by PCR using universal primers and the entire bla SHV were amplified by PCR using the primers outside the open reading frame (ORF) of SHV β lactamases; the PCR products of entire bla SHV were cloned into vector and the recombinant plasmids were transformed into the recipient strain for expression; the PCR products were also directly sequenced and analyzed; the clinical isolates of SHV producers were detected by PFGE. Results: Among 58 strains of ESBL producing Escherichia coli, only 3 isolates produced SHV β lactamases (5.2%), one produced SHV 11 (non ESBL), and two produced SHV 12(ESBL); PFGE patterns of SHV producing isolates were different. Conclusions: Types of SHV β lactamases are SHV 11 and SHV 12 in clinical isolates of ESBL producing Escherichia coli, and SHV ESBLs are not common in those strains; no clone spread in SHV β lactamase producing strains was found.