Culture-Independent Detection and Genotyping of Mycoplasma pneumoniae in Clinical Specimens from Beijing, China

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.