病毒性肝炎后肝硬化住院患者血液感染大肠埃希菌超广谱β-内酰胺酶基因型调查

Distribution of genotypes in ESBLs producing E. coli strains isolated from posthepatitic cirrhosis＇ patients with bloodstream infection

目的研究病毒性肝炎后肝硬化住院患者血液感染的大肠埃希菌产超广谱β内酰胺酶基因型。方法连续收集2011年1月至12月分离自病毒性肝炎后肝硬化住院患者血培养阳性的大肠埃希菌，VITEK-II鉴定细菌，K-β药敏试验检测细菌的药敏，多重PCR、PCR、测序及比对等对大肠埃希菌超广谱β内酰胺酶基因型进行分析。结果肝硬化主要原因为病毒感染，共收集79株大肠埃希菌，PCR扩增产物测序、比对：20株大肠埃希菌产TEM-1型β-内酰胺酶；仅有的-株产SHV-1型β-内酰胺酶，未检测出TEM型和SHV型超广谱β-内酰胺酶；40株产CTX-M型超广谱B-内酰胺酶，CTX-M-1群20株，CTX-M-9群26株，其中有6株菌同时产两群CTX-M型超广谱β-内酰胺酶，测序比对出CTX-M-3、CTX-M-15、CTX-M-14等八种基因型。结论病毒性肝硬化患者血液感染的大肠埃希菌超广谱B内酰胺酶最常见为CTX-M型，CTX-M-14是最常见的基因型。

Objective To study the genotype distribution of extended-spectrum β-1actamases （ESBLs） in ESBLs-producing Escherichia coli （E. coli） isolates from posthepatitic cirrhosis＇ patients with bloodstream infection. Methods E. coli were isolated in bloodstream from patients with posthepatitic cirrhosis between January and December in 2011. The strains were identified by VITEK-Ⅱ. The antibiol susceptibility tests were performed with K-B method. β-1actamases genes were detected muhi-PCR, PCR, sequence and blast. Results A total of 79 non-duplicate clinical isolates of E coli were consecutively collected from liver cirrhosis＇ patients with bloodstream infection. There were 20 isolates produced TEM-1 type 13-1actamases and 1 isolate produced SHV-1 typel3-1actamases. 40 clinical isolates were detected to produce CTX-M type ESBLs, there were 20 CTX-M-1 group and 26 CTX-M-9 group, including 6 stains habouring both CTX-M-1 and CTX-M-9 group. Eight CTX-M genotypes were confirmed by sequencing of the PCR products, including CTX-M-3, CTX-M-14, CTX-M-15, CTX-M-24, CTX-M-28, CTX-M-31, CTX-M- 65 and CTX-M-79. Conclusion CTX-M genotype ESBLs was the most popular extended-spectrum β- lactamases in E. coli isolated from liver cirrhosis＇ patients with bloodstream infection. The CTX-M-14 is the dominant epidemic type.