Abstract
A duplex real-time PCR assay was designed for simultaneous detection and genotyping of Mycoplasma pneumoniae (M. pneumoniae). The detection/typing performance of this duplex PCR method, targeting specific genes for M. pneumoniae type 1 (mpn 459) and type 2 (mpna 5864), was compared to that of the previously published MpP1 real-time PCR assay and the genotyping method for the adhesin P1 gene (mpn 141). A total of 1,344 throat swab specimens collected from patients in Beijing, China were tested for M. pneumoniae by bacterial culture, MpP1 real-time PCR assay, and our duplex PCR assay, and positive detection rates of 26.9%, 34.4%, and 33.7%, respectively, were obtained. The duplex PCR method demonstrated high sensitivity and accuracy for detecting and genotyping M. pneumoniae, and significant differences in genotyping ability were observed when compared to the conventional P1 gene-based method. M. pneumoniae type 1 was the predominate genotype from 2008 to 2012 in Beijing, and a shift from type 1 to type 2 began to occur in 2013. To our knowledge, this is the first reported incidence of a type shift phenomenon of M. pneumoniae clinical isolates in China. These genotyping results provide important information for understanding recent changes in epidemiological characteristics of M. pneumoniae in Beijing.