苯唑西林MIC≥0.5ug/ml折点对凝固酶阴性葡萄球菌耐药性高估情况分析

摘要

目的：了解使用苯唑西林MIC（最低抑菌浓度）≥0.5ug/ml的折点判断部份凝固酶阴性葡萄球菌为耐甲氧西林葡萄球菌对此类葡萄球菌耐药性高估的情况。方法：对73株苯唑西林MIC法耐药的凝固酶阴性非表皮葡萄球菌同时用头孢西丁纸片法扩散法（K-B法）检测，分析结果。结果：9株表现为敏感（抑菌圈≥25mm），占12%，其中6株苯唑西林MIC介于0.5-2ug/ml之间，3株苯唑西林MIC≥2ug/ml。头孢西丁敏感与耐药的两组菌对常用抗阳性球菌药物敏感性有明显差别。结论：对于苯唑西林MIC介于0.5-2ug/ml的凝固酶阴性的非表皮葡萄球菌，临床实验室应遵照美国临床和实验室标准化研究所（CLSI）指南，用头孢西丁K-B法或其它方法复核验证其耐药性，苯唑西林MIC≥2ug/ml的菌株，可直接报告为耐甲氧西林的葡萄球菌。%Objective:To investigate the overvalued situation about drug resistence that the pretive stangards of susceptibility results of oxacillin MIC≥0.5ug/ml are used to decide Methicillin resistant coagulase-nagative staphylococci. Methods:Analyze the results of 73 strains coagulase-negative Staphylococcus used cefoxitin diffusion method. Those Strains used oxacillin MIC method were showed drug resistance moreover they are not Staphylococcus epidermidis.Results:9 strains showed sensitive(inhibition zone≥25mm),accounting for 12%. Among them,6 Strains result of MIC method of oxacillin were between 0.5-2ug/ml, then 3 result ≥2ug/ml. The group which used cefoxitin showed drug resistance and Sensitive were showed significant differences to common Antibiotics.Conclusions:Clinical Laboratory should follow the guide of CLSI to use the cefoxitin K-B method to review the result of coagulase nagative staphylococci ,when they result of MIC method were between 0.5-2ug/ml. Which can be directly reported as methicillin-resistant Staphylococcus if the result of MIC method of oxacillin ≥2ug/ml.