Molecular Epidemiologic Study of Streptococcus pyogenes Analyzed by T protein Serotyping and Pulsed Field Gel Elecrophoresis(PFGE) in Normal Children

ABSTRACT

PURPOSE: In this study we tried to look at the spreading, duration of colonization, and acquisition of new streptococci which were obtained in one geographical area, as well as the bacteriologic and molecular epidemiology of normal school children carrying group A streptococci and their clonal relationship through the combined application of the serotype of T antigen and Pulsed Field Gel Electrophoresis(PFGE). METHODS: A total of 88 strains of group A streptococci were isolated from 396 normal school children. All isolates were classified in groups by Streptex and serotyped by T. agglutination. Restriction enzyme digestion of DNA was taken using Sma I. DNA fragments were separated by PFGE. RESULTS: A total of 33 strains were allocated their epidemiologic characteristics. Four out of 33 strains were not restricted by enzyme(Sma I). Twenty nine strains out of 33 strains showed 12 subtypes with 8-12 fragments between 40kbp and 500kbp of DNA fragments on PFGE. Eight strains of NT and T6 war same fragment patterns on PFGE, respectively. Three strains out of 4 strains of T8/25 were not restricted and the other one showed different, unique patterns. One strain out of 8 stains of T12 was not restricted, and the others were classified as 5 different subtypes. Two strains of Tl were different patterns from each other, and 2 strains of T4 showed the samefragment pattern CONCLUSION: T serotypes with PFGE will be useful as a screening and molecular epidemiologic method in a country where anti-M antisera is not available, after recognizing the advantages and disadvantages of M and T serotyping.