·DNA was obtained from sputum samples. The clinical significance of quantitative value of quantitative PCR (qPCR) was analyzed by combining with the results of routine culture and identification of sputum samples.

·There were 1 775 qualified sputum samples. The sensitivity of qPCR was 92.19% (59/64), the specificity was 89.60% (1 533/1 711), the positive predictive value was 24.89% (59/237), and the negative predictive value was 99.67% (1 533/1 538). The results of receiver operating characteristic ( ROC) curve analysis showed that the area under the curve of mecA quantitative value and C_T value were 0.755 and 0.770, respectively. The best critical values were 5.59 and 27.1, respectively. The sensitivity was 72.4% and 73.0%, and the specificity was 70.2% and 74.1%, respectively. When only Sa442 gene was positive, methicillin-susceptible Staphylococcus aureus was the main bacteria. When mecA value was greater than 5.59, or C_T value was less than 27.1, MRSA culture can be predicted to be positive.

·The quantitative detection of mecA and Sa442 genes in sputum samples can be used to quickly exclude the colonization and infection of MRSA in the early stage, helping to analyze the trend of different culture results.