Objective To evaluate accuracy of cefoxitin disk testing for detecting oxacillin resistance coagulase-negative staphylococci (MRCNS). Methods 139 clinical coagulase-negative staphylococci (CNS) were detected with ID32 STAPH. Cefoxitin disk and oxacillin disk testing were used to detect MRCNS. PBP2a was tested by latex agglutination us a reference method. Results 139 CNS isolates were identified to 8 species: Staphylococcus haemolyticus , S. epidermidis , S. hominis , S. xylosus , S. saprophyticus , S. auricularis , S. simulans and S. warneri. The sensitivity and specificity for cefoxtin disk and oxacillin disk testing were 99.0% vs. 86.0% and 91.7% vs. 74.4%, respectively. One S. epidermidis strain was identified to affect the sensitivity of cefoxitin disk testing. S. xylosus, S. warned, and S. saprophyticus were major species related to the decrease of specificity of cefoxitin disk testing. S. haemolyticus, S. hominis, S. simulans and S. auricularis were major species related to the decrease of sensitivity of oxacillin disk testing. And the decrease of specificity of oxacillin disk testing were mainly related to S. hominis , S. simulans , S. xylosus , S. auricularis , S. saprophyticus and S. warneri. Conclusions The accuracy of MRCNS detection by cefoxitin disk testing is varied due to different CNS species. So it is necessary to test PBP2a or mecA gene according to CNS species, especially for S. xylosus, S. warned and S. saprophyticus.%目的 评价凝固酶阴性葡萄球菌(CNS)菌种鉴定与苯唑西林耐药凝固酶阴件葡萄球菌(MRCNS)检测的准确性.方法 139株临床分离CNS,经ID 32 STAPH鉴定到种,用头孢西丁(FOX)、苯唑西林(OXA)纸片扩散法检测MRCNS,以Slidex MRSA detection乳胶凝集法检测青霉素结合蛋白2a(PBP2a)作为参考方法.结果 139株CNS鉴定为8个种,依次为溶血葡萄球菌、表皮葡萄球菌、人葡萄球菌、木糖葡萄球菌、腐生葡萄球菌、耳葡萄球菌、模仿葡萄球菌、沃氏葡萄球菌.FOX纸片法总的敏感度和特异度为99.0%和86.0%;OXA纸片法总的敏感度和特异度为91.7%和74.4%.影响FOX纸片法敏感度的菌种为1株表皮葡萄球菌;影响其特异度的菌种包括木糖葡萄球菌、沃氏葡萄球菌、腐生葡萄球菌;而影响OXA纸片法敏感度的菌种包括溶血葡萄球菌、人葡萄球菌、模仿葡萄球菌、耳葡萄球菌;影响其特异度的菌种包括人葡萄球菌、模仿葡萄球菌、木糖葡萄球菌、耳葡萄球菌、腐生葡萄球菌、沃氏葡萄球菌.结论 FOX纸片法检测MRCNS准确性因菌种不同有所差异,尤其应关注木糖葡萄球菌、沃氏葡萄球菌、腐生葡萄球菌的影响.建议检测MRCNS时,尽可能将CNS鉴定到种,视菌种必要时用PBP2a或mecA基因予以确认.
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