目的　了解肺炎支原体(MP)感染患儿MP流行株基因分型及其流行趋势变化。方法　采集2012年2月至2013年12月住院MP感染患儿的鼻咽分泌物，采用基于MP P1基因的巢式PCR及多重PCR方法进行MP基因亚型的监测，并分析其流行趋势。结果　在313例标本中检出P1-I型304例(97.12%)，P1-II型8例(2.56%)，V2型变异株1例(0.32%)，基因测序结果与巢式多重PCR结果相符合。结论　巢式多重PCR方法能够直接有效地对MP进行P1基因分型，研究期间MP感染株以P1-I型为主，发现1例V2变异株。

　Objective　To analyze the genotype and variation of Mycoplasma pneumonia (MP) strains isolated from children with MP infection in Soochow area. Methods　The nasopharyngeal secretions from hospitalized children with MP infection were collected during January 2012 and December 2013. The nested-multiplex PCR based on MP P1 gene was performed to detect the subtype of MP gene. Results　In 313 samples, 304 (97.12 %) samples were classified as P1-I type and 8 (2.56%) samples were classified as P1-II type and one (0.32%) was V2 variant. Gene sequencing results were consistent with nested-multiple PCR results. Conclusions　Nested-multiplex PCR is a reliable method for genotyping of MP P1 gene. During the study period, P1-I type was the common genotype and only one case of V2 variant was found.