济南地区异质性万古霉素中介金葡菌的分离率及方法研究

目的  了解济南地区临床MRSA标本中异质性万古霉素中介金葡菌(hVISA)的分离率，并对三种筛选方法进行探讨。方法  对216株临床分离的耐甲氧西林金葡菌（MRSA）分别进行2μg /mL万古霉素（BHIV2)、4μg/mL万古霉素（BHIV4)及5μg/mL替考拉宁（BHIT5)脑心浸液琼脂筛选法初筛，对阳性菌株进行macroEtest(MET)法及改良菌群分析策略-曲线下面积法（PAP-AUC）确认。结果  BHIV2、BHIV4、BHIT5筛选法初筛的菌株数分别为143、19和110株，初筛菌株最终确认29株，确认率分别为16.1%、73.7%和19.1%，则济南地区hVISA的分离率至少为13.4%（29/216）。结论  在济南地区临床分离的MRSA菌中hVISA占有一定比例；在三种筛选方法中，BHIV2和BHIT5筛选法的敏感性高于BHIV4筛选法，特异性低于BHIV4筛选法，而BHIV2和BHIT5筛选法之间无差异。

Prevalence and screening methods of heteroresistant vancomycin intermediate staphylococcus aureus in Jinan region

Objective  To investigate the prevalence of heteroresistant vancomycin-intermediate staphylococcus aureus and compare three screening methods. Methods  216 strains of methicillin-resistant staphylococcus aureus(MRSA) were preliminarily screened by brain heart infusion agar with 2mg/liter vancomycin (BHIV2), 4mg/liter vancomycin (BHIV4) or 5mg/liter teicoplanin (BHIT5). Positive strains were confirmed by macroEtest(MET) and population analysis profile-area under the curve（PAP-AUC）. Results  In 216 strains of clinical MRSA, isolating rate of hVISA was at least 13.4%. In BHIV2, BHIV4 and BHIT5 screening methods, the preliminarily screened positive strains were 143, 19 and 110, respectively, with finally confirmed rates of 16.1%, 73.7% and 19.1%, respectively. Conclusion  Some certain strains of hVISA exist in MRSA isolated from clinics of Jinan region . Among the three methods, sensitivities in BHIV2 and BHIT5 methods are higher than that in BHIV4 method. However, specificities in BHIV2 and BHIT5 methods are lower than that in BHIV4 method. There are no significant differences in sensitivity and specificity between BHIV2 and BHIT5 methods.