Serotyping of Group A Streptococci Isolated from Healthy School Children and Patients with Pharyngotonsillitis

Cha, Sungho; Park, Yongho; Suh, Jintae; Johnson, Dwight

Abstract

BACKGROUND
To evaluate serological typing of T(epidemiologic marker) and M protein(major virulence antigen) is important to understand pathogenesis and epidemiology of streptococcal infection. The purpose of this study is to find out whether there were major difference in distribution of serotypes isolated from healthy school children and patients with pharyngotonsillitis, and to characterize the geographical differences in distribution of the serotypes. METHOD: Twenty-three strains of group A streptococci were isolated from healthy school children in two different areas(Dongdaemun-Ku and Kangsuh-Ku) in Seoul in April and July 1996. 23 strains came from patients living in Dongjak-Ku with pharyngotonsillitis in April 1996. All isolated were serotyped by T agglutination, M precipitation and opacity factor at the WHO Collaborative Center for Reference and Research on Streptococci, University of Minnesota, Minneapolis.
RESULTS
89.1% of the strains were typable by T agglutination, 56.5% by M precipitation, and 52.2% were positive in opacity factor. T types 1, 25, 4, and 12 accounted for 65.2% of patients with pharyngotonsillitis, T types 12, and 25 accounted for 71.5% of healthy children in Dongdaemun-Ku, and T types 28, 6, and 3 accounted for 62.6% of healthy children in Kangsuh-Ku. T types 1, 25, 28, 12, 4 and M types 1, 75, 28, 4, 12 were typed in decreasing order.
CONCLUSION
We characterized the differences in serotypes of group A streptocpcci between healthy children and patients. The periodic and seasonal serotyping analysis is important in monitoring and understanding of the epidemiologic patterns of group A streptococci.