Farahani Abbas, Mohajeri Parviz, Gholamine Babak, Rezaei Mansour, Abbasi Hassan
Student Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran.
Department of Microbiology, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
N Am J Med Sci. 2013 Nov;5(11):637-40. doi: 10.4103/1947-2714.122305.
Staphylococcus aureus is known as a powerful pathogen that causes various infections. Emergence of methicillin-resistant S. aureus (MSRA) is responsible for nosocomial and community-acquired infections worldwide.
The present study aimed to evaluate the performance and ability of eight different phenotypic and genotypic methods for the detection of MSRA.
A total of 186 S. aureus isolates were defined as methicillin-susceptible S. aureus (MSSA; 95) and MSRA (91) using polymerase chain reaction (PCR) as the gold standard. Susceptibility to methicillin was investigated using oxacillin, methicillin, cefotetan, cefoxitin, and cefmetazole disks, by oxacillin Adata Tab and strips. For all S. aureus isolates minimal inhibitory concentrations of oxacillin were determined using the broth microdilution method according to Clinical and Laboratory Standards Institute guidelines.
Among the diagnostic methods studied, broth microdilution and the cefoxitin disk had the highest specificity (98.9 and 94.7%), sensitivity (100 and 98.9%), and concordance with PCR results (98.9 and 93.6%). The cefotetan and cefmetazole disks had the lowest concordance with PCR results.
Our results suggest that microdilution and cefoxitin disk methods have high sensitivities compared with other methods for detection of MSRA. The cefoxitin disk method may be preferred in clinical laboratories because it is easy to perform and does not require special equipment.
金黄色葡萄球菌是一种可引发多种感染的强大病原体。耐甲氧西林金黄色葡萄球菌（MRSA）的出现导致了全球范围内的医院感染和社区获得性感染。
本研究旨在评估八种不同表型和基因型方法检测MRSA的性能和能力。
以聚合酶链反应（PCR）作为金标准，共186株金黄色葡萄球菌分离株被定义为甲氧西林敏感金黄色葡萄球菌（MSSA；95株）和MRSA（91株）。使用苯唑西林、甲氧西林、头孢替坦、头孢西丁和头孢美唑纸片，通过苯唑西林Adata Tab和试纸条研究对甲氧西林的敏感性。根据临床和实验室标准协会指南，采用肉汤微量稀释法测定所有金黄色葡萄球菌分离株对苯唑西林的最低抑菌浓度。
在所研究的诊断方法中，肉汤微量稀释法和头孢西丁纸片法具有最高的特异性（分别为98.9%和94.7%）、敏感性（分别为100%和98.9%）以及与PCR结果的一致性（分别为98.9%和93.6%）。头孢替坦和头孢美唑纸片法与PCR结果的一致性最低。
我们的结果表明，与其他检测MRSA的方法相比，微量稀释法和头孢西丁纸片法具有较高的敏感性。头孢西丁纸片法在临床实验室中可能更受青睐，因为它操作简便，且不需要特殊设备。
