关键词: 肠球菌, 耐药, 万古霉素, 猪场

Abstract: This experiment was conducted to investigate the isolation ratio， the phenotype and the genotype of Vancomycin-resistant Enterococci (VRE) from 3 different pig farms and provide basic data for the epidemiology of VRE. A broth dilution method recommended by American Society of Clinical and Laboratory Standards Institute (CLSI) was used to determinate the resistant phenotypic, a PCR method was used to identify Enterococci and detect Vancomycin-resistant gene at the same time. The results were as follows: 30 strains of VRE were isolated from 250 samples of 3 different pig farms. The isolation ratio of VRE was highest in the sucking piglets，followed in weaned pig, milking sow, farrowing sow, and hog, and lowest in boar- Sensitivity test results of VRE showed that the resistance rate of oxytetracycline was highest (93.3%), and the sensitive rate of ampicillin was highest (80%). Resistance gene of 30 VRE strains were detected by PCR method and there were two VanA-positive，12 VanB-positive，7 VanC1-positive，5 VanC2/3-positive in all the VRE, though there were no Van gene amplified from 4 strains of VRE. The isolation ratio of VRE from 3 pig farms was related to the extent of antibiotic usage. The VRE had different resistant rate to 6 kinds of antibiotics. There was highly agreement between phenotypes and genotypes in 30 strains of VRE．

Key words: Enterococci, resistance, Vancomycin, pig farm