Abstract: Objective To investigate the distribution of the emm types and superantigens of group A streptococcal (GAS) isolated from Chinese children. Method 222 GAS isolates obtained from five Children's Hospital of China during 2005-2006 were studied, emm types were performed by PCR and sequencing. And the eight superantigen (SAg) genes (speA, speC, speH, speI, speG, speJ, ssa, and SMEZ) were detected by PCR. Results Nine emm types were determined，of which emm12 (55.86%) and emm1 (39.64%) were the most prevalent types. The GAS isolates carried six or more than six SAg genes were 78.39% of all the isolates in this study. The SAg gene profiles were closely associated with the emm type. Conclusion This study showed that the distribution of the emm types of S. pyogenes isolated from Chinese children were intensively. The SAg genes appeared to be associated with the emm type, thereby aiding in vaccine development in China.

Key words: Group A streptococcus, emm gene sequence, superantigen