异质性万古霉素中介金黄色葡萄球菌分离率与检测方法评价

Prevalence and detection methods of hetero-resistant vancomycin intermediate Staphylococcus aureus

目的了解医院临床耐甲氧西林金黄色葡萄球菌(MRSA)中异质性万古霉素中介金黄色葡萄球菌(hVISA)的分离率,为寻求一种可用于实验室筛选hVISA简便有效的检测方法。方法收集2014年3月-2015年4月于临床分离的MRSA 205株,分别用16g/L胰酶消化酪蛋白和4μg/ml万古霉素脑心浸液琼脂筛选法(CBHIV4)、宏量E-test法(MET)、E试验法(GRD)及菌群分析曲线(PAP/AUC)法检测hVISA,对比3种检测方法的敏感性及特异性。结果 PAP/AUC、CBHIV4、MET、GRD的4种方法检测hVISA阳性菌株分别为12、18、54、39株;以PAP/AUC作为金标准,CBHIV4、MET、GRD的3种检测方法敏感度分别为80.0%、50.0%、58.3%,特异度分别为96.0%、80.0%、85.7%。结论 16g/L胰酶消化酪蛋白和4μg/ml万古霉素脑心浸液琼脂筛选法有较高的敏感性和特异性,可作为hVISA的初筛方法,代替较为繁琐的菌群分析曲线,并减少E-test纸片的使用,降低检测成本。

OBJECTIVE To research the prevalence of hetero-resistant vancomycin intermediate Staphylococcus aureus（hVISA）among clinical methicillin-resistant Staphylococcus aureus（MRSA）in the hospital and explore a simple and effective method for detecting hVISA.METHODS Totally 205 clinical strains of MRSA were collected from Mar.2014 to Apr.2015.The hVISA isolates were detected by CBHIV4（brain heart infusion agar containing 4μg/ml vancomycin and 16g/L casein）,MET（E-test macromethod）,GRD（E-test）and PAP/AUC（population analysis profiles/area under the curve）.The sensitivity and specificity of CBHIV4 by casein,MET,PAP/AUC and GRD methods were compared.RESULTS The positive strains of hVISA were 12,18,54,39 respectively by the four methods.Taking PAP/AUC method as the gold standard,the sensitivity by CBHIV4,MET and GRD was 80.0%,50.0%,58.3%,and the specificity was 96.0%,80.0%,85.7%respectively.CONCLUSION The CBHIV4 had both high sensitivity and specificity and could be used as the primary screening method of hVISA to reduce the tedious workload of conducting PAP/AUC and the using of E-test and reduce testing costs