头孢西丁扩散法检测耐甲氧西林葡萄球菌异质性耐药菌株的评价

目的:评价头孢西丁扩散法检测耐甲氧西林葡萄球菌异质性耐药菌株的可靠性和临床实用性.方法:将临床分离得到的葡萄球菌310株,按美国临床实验室标准化委员会(NCCLS)标准操作规程进行苯唑西林纸片扩散法、头孢西丁纸片扩散法、苯唑西林琼脂稀释法实验,并以PCR检测葡萄球菌mecA基因为判断标准,比较4种方法的敏感性及特异性.结果:经mecA基因检测,耐甲氧西林金黄色葡萄球菌(MRSA)为57.1%(113/198),耐甲氧西林的凝固酶阴性葡萄球菌(MRCNS)为62.5%(70/112).头孢西丁纸片扩散法检测MRSA的敏感性和特异性均为100%,检测MRCNS敏感性为98.6%,特异性为100%.结论:头孢西丁纸片扩散法操作简便,结果可靠,可作为临床实验室检测耐甲氧西林葡萄球菌的常规方法.

Cefoxitin disk diffusion test in the detection of MRSheterogenic drug-resistant strains

Objective To evaluate the reliability and clinical practicability of cefoxitin disk diffusion test in the detection of methicillin-resistant staphylococcus (MRS) heterogenic drug-resistant strains. Methods Three hundred and ten strains of staphylococcus isolated from clinics were detected by the oxacillin disk diffusion test, the cefoxitin disk diffusion test as well as the oxacillin agar dilution test according to the standard operation procedures of NCCLS, and the detection of mecA gene of staphylococcus was used as a criterion. The sensitivities and specitivities of the 4 methods were compared. Results By the detection of mecA gene, the ratio for MRSA was 57.1%(113/198) and the ratio for MRCNS was 62.5%(70/112). Both the sensitivity and specificity of cefoxitin disk diffusion test in the detection of MRS were 100%, and those in the detection of MRCNS were 98.6% and 100%. Conclusion Cefoxitin disk diffusion test is reliable, simple and convenient, and it can be used as a conventional method for the detection of MRS in clinical laboratories.