[Study on the distribution of superantigen of group A streptococcus isolated from children in Beijing, 2011].
OBJECTIVE
To analyze the prevalence of super-antigens (SAgs) of group A streptococcus (GAS)isolated from Beijing pediatric patients in 2011, and to explore the relationship between emm types, characteristics of patients and SAgs.


METHODS
A total of 635 isolates of GAS were collected from children in 36 hospitals in Beijing from May to July, 2011. Thirteen currently known SAg genes were tested by real-time PCR, and emm gene was performed by PCR and sequencing of N-terminal gene fragments of M protein.


RESULTS
Prevalence rates of 13 SAg genes speA, speB, speC, speF, speG, speH, speI, speJ, speK, speL, speM, smeZ, ssa were 22.4%, 100.0%, 99.4%, 99.7%, 99.7%, 76.4%, 76.2%, 21.7%,0.6%, 1.1%, 2.2%, 99.7% and 98.0%, respectively. A total of 26 SAgs profiles were observed according to the SAgs inclusion. There were significant differences in frequencies of speA, speH, speI and speJ between emm1 and emm12 strains (P < 0.05). In isolates from patients with pharyngeal infection, the prevalence rates for speK and speL were higher while the frequency for ssa was lower than that from scarlet fever cases (P < 0.05).


CONCLUSIONS
The frequencies of speB, speF, smeZ, speG, speC, and ssa were high among strains isolated while speM, speL and speK were relatively low from children in Beijing, 2011. SAg genes appeared to be associated with the emm types. In this study, differences of frequency for speA and speC from strains collected from patients with scarlet fever and pharyngeal infection had not been found.
Institute for Infectious Disease and Endemic Disease Control, Beijing Centers for Disease Control and Prevention, Beijing 100013, China.
Xiaomin
X
Peng
Institute for Infectious Disease and Endemic Disease Control, Beijing Centers for Disease Control and Prevention, Beijing 100013, China.
Shuang
S
Liu
Institute for Infectious Disease and Endemic Disease Control, Beijing Centers for Disease Control and Prevention, Beijing 100013, China.
Peng
P
Yang
Institute for Infectious Disease and Endemic Disease Control, Beijing Centers for Disease Control and Prevention, Beijing 100013, China.
Jing
J
Li
Institute for Infectious Disease and Endemic Disease Control, Beijing Centers for Disease Control and Prevention, Beijing 100013, China.
Daitao
D
Zhang
Institute for Infectious Disease and Endemic Disease Control, Beijing Centers for Disease Control and Prevention, Beijing 100013, China.
Shujuan
S
Cui
Institute for Infectious Disease and Endemic Disease Control, Beijing Centers for Disease Control and Prevention, Beijing 100013, China.
Shuangsheng
S
Wu
Institute for Infectious Disease and Endemic Disease Control, Beijing Centers for Disease Control and Prevention, Beijing 100013, China.
Yimeng
Y
Liu
Institute for Infectious Disease and Endemic Disease Control, Beijing Centers for Disease Control and Prevention, Beijing 100013, China. Email: bjcdcxm@126.com.
Quanyi
Q
Wang
D000293:Adolescent; D000942:Antigens, Bacterial / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D017422:Sequence Analysis, DNA; D013290:Streptococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification
D000942:Antigens, Bacterial