实时荧光核酸恒温扩增技术在检测分泌物中MRSA的应用

目的 对实时荧光核酸恒温扩增技术（simultaneous amplification and testing method，SAT）检测创面分泌物中耐甲氧西林金黄色葡萄球菌（MRSA）核酸试剂盒（RNA恒温扩增）应用进行评价。方法 收集我院临床各科室于2016年12月至2017年1月送至检验科微生物室347份分泌物标本，分别用实时恒温扩增技术和ChromID MRSA产色平板筛选MRSA。当SAT法和MRSA培养结果不相符时，进行冻存的备用标本PCR扩增、第三方测序，以MRSA培养结果加PCR测序结果作为本次试验“扩大金标准”，计算SAT的灵敏度、特异性、阳性预测值、阴性预测值,并进行相应的统计学分析。结果 以ChromID MRSA产色平板筛选加PCR测序作为“扩大金标准”，SAT法检测MRSA的敏感度为90.91%、特异度为99.40%、阳性预测值为83.33%、阴性预测值为99.40%，对MRSA的最低检出下线为102拷贝/mL，Kappa系数为0.85。结论 SAT技术在检测分泌物中MRSA具有很高的灵敏度、特异性，而且准确、可靠，与传统的细菌培养相比耗时短，为MRSA的实验室诊断提供新的检测方法。

Simultaneous amplification and testing method for the detection of MRSA

Abstract: Objective To evaluate the diagnostic value of simultaneous amplification and testing method (SAT) for the detection of MRSA in secretions. Methods A total of 347 secretion specimens were collected from November 2016 to January 2017. All of the specimens were inoculated on a ChromID® MRSA agar plate for culturing and detection with simultaneous amplification and testing assay. When the result of SAT method was not consistent with that of MRSA culture, the backup specimens were amplified by using PCR-sequencing. Using MRSA culture plus PCR-sequencing as the reference method, the sensibility, specificity, positive and negative predictive values of the SAT assay were analyzed. Results The sensitivity of MRSA detection by SAT was 102 copies/mL. The Kappa value between SAT and MRSA culture plus PCR-sequencing was 0.85, and the sensibility, specificity, positive-predictive value and negative predictive value of the SAT assay were 90.91%, 99.40%, 83.33%, and 99.40%, respectively. Conclusion The SAT is a sensitive, specific, accurate, rapid and reliable method for detecting MRSA in secretions, and it is much more time-saving than traditional culture. The SAT would be a new potential method for rapid diagnosis of MRSA infection.