37株耐万古霉素屎肠球菌基因型及同源性分析

Genotype and Homology Analysis in 37 Vancomycin-resistant Enterococcus faecium Strains

目的检测37株耐万古霉素屎肠球菌（VREFm）的基因型以利于临床治疗选药，重复基因外回文序列-聚合酶链反应（REP-PCR）同源性分析为分子流行病学提供依据。方法依据2006年美国临床实验室标准化研究所（CLSI）推荐的纸片扩散法和琼脂稀释法对VREFm进行药敏试验；PCR方法检测万古霉素的耐药基因；用REP-PCR进行同源性分析。结果37株屎肠球菌对万古霉素、替考拉宁、红霉素和氨苄西林均100．0％耐药，万古霉素MIC〉512μg／ml，基因型均为vanA；耐药率左氧氟沙星为89．2％、庆大霉素为86．5％、环丙沙星为91．9％、呋喃妥因为59．5％、氯霉素为5．4％；37株VREFm扩增出3～14条带，大小在100～2000bp之间，分为6个型。结论37株VREFm表型与基因型一致；VREFm对多种抗菌药物耐药；REP-PCR方法简便、快速、花费低，可用于肠球菌属同源性检测。

OBJECTIVE To detect the genotype in 37 vancomycin-resistant Enterococcus faecium （VREFm） strains to guide the clinical treatment. Results of homology provide the proof for molecular epidemiology. METHODS According to the guideline of Clinical Laboratory Standardization Institute of the USA （CLSI）, antimicrobial susceptibility tests were performed with disk diffusion and agar dilution method; to detect vancomycin resistant gene by PCR. To analyze the homology by repetitive extragenic palindromic element-PCR （REP-PCR） method. RESULTS Resistance rates to vancomycin and teicoplanin were 100.0% and 100.0^ in 37 VREFm, respectively. It had minimum inhibitory concentration （MIC）〉512 μg/ml for vancomycin. Thirty seven VanA genes were detected in 37 VREFm. Thedrug resistance rates to erythromycin, ampicillin, levofloxacin, gentamicin, ciprofloxacin, nitrofurantoin （Euradantin） and chloramphenicol were 100. 0%, 100. 0%, 89. 2%, 86. 5%, 91.9%, 59.5%, and 5.4% ,respectively. The REP-PCR generated 3-14 bands between 100 and 2000bp. They were divided into six types. CONCLUSIONS There is 100. 0% agreement between phenotypes and genotypes in VREFm. VREFm are multiresistant. REP-PCR method is simple, rapid, and with lower cost to detect the homology in enterococci.