应用头孢西丁纸片扩散法检测耐甲氧西林葡萄球菌

目的 比较头孢西丁纸片扩散法与传统的苯唑西林纸片扩散法对耐甲氧西林葡萄球菌(MRS)检测的效率.方法 收集66株葡萄球菌,分别采用苯唑西林琼脂平板筛选试验、头孢西丁纸片扩散法、苯唑西林纸片扩散法来检测MRS,结果以苯唑西林琼脂平板筛选结果为对照,分别比较头孢西丁和苯唑西林纸片扩散法的特异性和敏感性. 结果 66株葡萄球菌中,37株金黄色葡萄球菌经苯唑西林琼脂平板筛选判定为耐甲氧西林金黄色葡萄球菌(MRSA)的有15株,29株凝固酶阴性的葡萄球菌有24株判定为耐甲氧西林凝固酶阴性的葡萄球菌(MRCNS).与苯唑西林琼脂平板筛选法比较,头孢西丁纸片扩散法检测MRSA的敏感性和特异性均为100%,而苯唑西林纸片扩散法其敏感性和特异性分别为93%(14/15)和91%(20/22);头孢西丁纸片扩散法检测MRCNS的敏感性和特异性均为100%,而苯唑西林纸片扩散法其敏感性和特异性分别为96%(23/24)和40%(2/5).结论 头孢西丁纸片扩散法对MRS检出优于苯唑西林纸片扩散法.

Detection of methicillin-resistant staphylococcus by using cefoxitin disk diffusion method

Objective To compare the efficiency between the cefoxitin disk diffusion test and oxacillin disk diffusion test on the detection of methicillin-resistant staphylococcus(MRS).Methods Sixty-six strains of staphylococcus were collected and sensitivity test were done by using the oxacillin agar-plate screen test,the cefoxitin disk diffusion test and oxacillin disk diffusion test respectively.The sensitivity and specificity of the cefoxitin disk diffusion test and the oxacillin disk diffusion test were compared by using the results of oxacillin agar-plate screen test as a "gold standard".Results Of all the 66 strains of staphylococcus,there were 15 strains of methicillin-resistant staphylococcus aureus(MRSA) in all 37 strains Staphylococcus aureus,and 24 strains of methicillin-resistant staphylococcus in all 29 strains coagulase-negative staphylococcus(MRCNS).Compared with the results of the oxacillin agar-plate screen test,the percentage of sensitivity(%)/specificity(%) were as fallows: the cefoxitin disk diffusion test were 100/100 on detection of MRSA and MRCNS;the oxacillin disk diffusion test were 93/91 on detection of MRSA and 96/40 on detection of MRCNS respectively.Conclusion The cefoxitin disk diffusion test is superior to the oxacillin disk diffusion test and can improve the reliability of routine tests for detection of MRS.