异质性万古霉素中介金黄色葡萄球菌的分离及检测方法的建立

目的 了解异质性万古霉素中介金黄色葡萄球菌(h-VISA)的分离情况,并筛选简便可行的h-VISA的检测方法.方法 采用琼脂稀释法和E-test法对分离出的113株金黄色葡萄球菌进行检测,筛选出的可疑h-VISA用菌谱分析法进行确认,并对文献推荐的几种方法的筛选效果进行比较.结果 检测到1株万古霉素的MIC为3 μg/mL和2株MIC为4 μg/mL的MRSA,为万古霉素敏感性减低的金黄色葡萄球菌,其中1株MIC为4 μg/mL的MRSA经菌谱分析法证实为h-VISA,本次113株实验菌株h-VISA的检出率为0.88%.结论 通过实验证实K-B法并不是检测h-VISA的理想方法,而菌谱分析法则较为有效,分离率为8.3%,且在本实验中灵敏度可达10-8.本院分离的MRSA中已出现万古霉素敏感性减低菌株,并分离出1株h-VISA,可见,MRSA对万古霉素的异质性中介耐药不容忽视,应引起国内医学界的广泛重视.

Construction of new methods for the isolation and detection of heterogeneous vancomycin intermediate Stapylococus aureus

Objective To investigate the prevalence of heterogeneous vancomycin intermediate Stapylococus aureus(h-VISA) and develop a new method for the detection of h-VISA.Methods 113 strains of Staphylococcus aureus(SA) were screened by agar dilution method and E-test method.The resistant strains were confirmed by population analysis.Results Three strains of SA were with reduced susceptibility to vancomycin,including one strain with minimal inhibitory concentration(MIC) for 3 μg/mL and two strains with MIC for 4 μg/mL.One strain with MIC for 4 μg/mL was confirmed as h-VISA,and the detection rate was 0.88%(1/113).Conclusion Population analysis could be more effective than disc agar diffusion method,and the former might be with high sensitivity to 10-8.More attention should be paid to the emerge of strains with reduced susceptibility to vancomycin and h-VISA.