ABSTRACT
Objective To investigate the prevalence of Mycoplasma pneumoniae ( Mp) infection in children in Hengyang from 2013 to 2016 and to analyze the p1 genotypes of the isolated Mp strains by using polymerase chain reaction-restriction fragment length polymorphism ( PCR-RFLP) , nested polymerase chain reaction (nPCR) and rapid-cycle polymerase chain reaction (Rapid-Cycle PCR).Methods Throat swab samples of children with acute respiratory tract infection were collected from four hospitals in Hengyang , Hu-nan Province from 2013 to 2016.Mp strains in these samples were identified by PCR amplification of the 16S rRNA gene.PCR-RFLP, nPCR and Rapid-Cycle PCR were performed for Mp p1 genotyping in order to fur-ther analyze the genotypes of Mp strains circulating in Hengyang .Results A total of 109 clinical strains of Mp were identified from the 984 throat swab samples .The sensitivities of PCR-RFLP and nPCR for genoty-ping MP strains were both 100％, while that of rapid-Cycle PCR was 98 .17％.All of the three methods showed 100％specificity for genotyping.Of all isolated Mp strains, 78.90％ were p1 gene type Ⅰ and 21.10％were p1 gene typeⅡ(t=93.239, P=0.01).From 2013 to 2016, the annual isolation rates of p1 gene type Ⅰ and type Ⅱ strains were 93.10％, 87.5％, 76.92％, 65.79％ and 6.90％, 12.5％, 23.08％, 34.21％, respectively.The rate of Mp p1 gene type Ⅰinfection decreased over year , while that of p1 gene type Ⅱinfection increased gradually .Conclusion PCR-RFLP, nPCR and rapid-Cycle PCR are reliable for genotyping of Mp p1 gene.The predominant genotype of Mp strains circulating in Hengyang is p 1 gene type Ⅰ, but the incidence of p 1 gene type Ⅱinfection gradually increases from 2013 to 2016 .