Group A streptococcal throat colonization is a dynamic phenomenon

In order to gain knowledge about the nature of group A streptococcal throat colonization of asymptomatic children, we studied a cohort of healthy chil dren selected at random. Those with throat cultures positive for group A St reptococci (GAS) were followed for 5 weeks. Repeat throat swabs were obtain ed at weekly intervals for antigen detection and culture. GAS obtained were serotyped for T antigen. Twenty-two children were identified as having GAS and 50% had a positive antigen test and culture at least five times in 6 w eeks. There was no consistent pattern in the typeable organisms. Most indiv iduals had more than one T-type alternating with non-T-typeable organisms. We conclude that colonization may be a dynamic process involving numerous o rganism serotypes, which wax and wane.