耐万古霉素肠球菌表型测定及基因分型

Detection of Phenotype and Genotype from Vancomycin-resistant Enterococci

目的对耐万古霉素肠球菌(VRE)的确证试验,同时对VRE进行基因分型。方法采用浓度梯度法及含6μg/ml万古霉素的脑心浸液琼脂平板上点种,确证6株VRE,聚合酶链反应检测vanA、vanB、vanC,并对1株vanB的屎肠球菌进行测序,聚合酶链反应检测ermB、qacE△1-sul1基因。结果160株肠球菌属用微量肉汤稀释法粗筛出17株最低抑菌浓度(MIC)≥4 mg/L的肠球菌属,用浓度梯度法只有6株MIC≥4 mg/L的肠球菌属,并在含6μg/ml万古霉素的脑心浸液琼脂平板上都有不同程度的生长;17株肠球菌属对红霉素ermB耐药基因检测,有10株含有ermB基因;未检测到qacE△1-sul1基因。结论VRE确认试验以及准确检测其MIC值是筛查VRE的可靠方法,对VRE的基因分型,为VRE的进一步研究及流行病学分析提供有价值的信息。

OBJECTIVE To explore the infection rate with identifying test of vancomycin-resistant enterococci （VRE） from clinical samples, that is 3.7 percent and to genotype VRE. METHODS vanA, vanB and vanC were detected by PCR in six isolates of VRE which were identified by the broth microdilution susceptibility test and Etest. The one of vanB was further analyzed with DNA sequence and ermB, qacE△1-sul1 gentypes were detected. RESULTS Seventeen isolates of enterococci （MIC≥4 μg/ml） were obtained of 160 isolates of enterococci which came from Jiangxi Children＇s Hospital by microdilution methods, while 6 isolates were gotten by Etest. It demonstrated that susceptibilities of VRE were different in four in vitro susceptibility testing methods. VRE showed resistance to erythromycin（10/17）, disinfectant/sulfanilamide（0/17）. CONCLUSIONS VRE screening test and the determination of MIC are reliable in finding VRE. VRE genotype is valuable on further research and epidemiological survey of our province.