头孢西丁和拉氧头孢低密度菌落法检测耐甲氧西林凝固酶阴性葡萄球菌

Detection of Methicillin-Resistant Coagulase-Negative Staphylococci Using Cefoxitin and Moxalactam Disc Diffusion Methods

目的评价头孢西丁和拉氧头孢低密度菌落法检测耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)的可靠性和临床实用性。方法临床收集的93株凝固酶阴性葡萄球菌(CNS),按法国生物学会(CASFM)推荐的头孢西丁和拉氧头孢30μg低密度菌落法检测MRCNS,并与mecA基因PCR扩增法进行比较。结果以mecA基因PCR扩增法为金标准,其中MRCNS56株(阳性率60.2%),低密度菌落法头孢西丁的敏感性和特异性分别为94.6%和100%,拉氧头孢的敏感性和特异性分别为100%和97.3%。结论头孢西丁和拉氧头孢低密度菌落法是鉴定异质性MRCNS的良好方法。

Objective To evaluate the reliability and clinical practicability of cefoxitin and moxalactam disc diffusion methods to detect methicillin-resistant coagulase-negative staphylococci （MRCNS）. Methods 93 strains of coagulase-negative staphylococci （CNS） isolated from the hospital were used in this study. Cefoxitin and moxalactam disc diffusion methods with low-density inoculum （CASFM） were compared with mecA gene PCR assay. Results Using mecA gene PCR assay as the ＂gold standard＂, 56 out of 93 strains （60.2%） of MRCNS were identified. The sensitivity and specificity of cefoxitin disc diffusion method was 94.6% and 100%, respectively. The sensitivity and specificity of moxalactam disc diffusion method was 100% and 97.3%, respectively. Conclusion Cefoxitin and moxalactam disc diffusion methods are specific in the identification of MRCNS.