猪源产志贺毒素大肠埃希茵耐药性及超广谱β内酰胺酶基因型分析

目的了解我国猪源产志贺毒素大肠埃希菌（Shigatoxin-producingEscherichiacoli，STEC）产超广谱8内酰胺酶（Extended—spectruml β-lactamases，ESBLs）情况及其基因型。方法对22株分离自重庆地区2个规模化养殖场健康猪粪的STEC菌株进行药物敏感性检测、ESBLs表型确证及7种类型（blaSHV，blaLEN,blaOKP，blaTEM，blaCTX-M,blaGES及blaKPC）ESBLs基因型PCR检测和测序分析。结果22株携带stx2e的STEC菌株中2株对所有23种测试抗生素敏感，其余菌株除对亚胺培南和美罗培南敏感外，对其他抗生素均存在不同程度耐药。10株sTEc菌株（占45．45％）产ESBLs酶。PCR检测其中1株为blaCTX-M-1基因型，其余9株为blaCTX-M-9 ＋blaTEM-1基因型。结论重庆地区猪源STEC中存在较高比例的产ESBLs菌株。在加强人和动物STEC感染检测与监测的同时，应进行细菌耐药性监测。

Analysis of antimicrobial resistances and ESBLs genotypes of Shiga toxin-producing Escherichia coli iso- lates from pigs

Objective To ascertain the prevalence and genotypes of extended-spectrum β-1actamases （ESBLs） produced by Shiga toxin-producing Escherichia coli （STEC） strains isolated from healthy pigs in China. Methods Twenty-two STEC strains were isolated from pig feces from 2 large pig farms. A antimicrobial resistance assay and ESBL test were performed, ESBLs were genotyped using 7 genes （blaSHV, blaLEN , blaOKP, blaTEM, blaCTX- M, blaG Es, and blaKPC）, and DNA sequencing was performed. Results Two of the 22 STEC isolates that carried stx2e were susceptible to 23 antimi- crobials. Other STEC isolates had different patterns of resistance except to imipenem and meropenem. Ten STEC isolates were ESBL-positive （45. 450/00）; 1 was the blaCTX-M-1 genotype while the rest 9 were the blaCTC-M-＋blaTEM-1 genotype. Conclusion A high proportion of STEC isolates in Chongqing are ESBL-producing strains. Antimicrobial resistance should be monitored while testing for STEC infections in human and animals.