Outbreak of group A streptococcus septicemia in children. Clinical, epidemiologic, and microbiological correlates.

To determine the epidemiologic, clinical, and microbiological features of group A streptococcus septicemia in children. A descriptive series of 34 cases over an 11-year period from 1980 through 1990. An academically affiliated tertiary-care pediatric hospital, the principal referral center for the state of Colorado and surrounding states. Thirty-four patients with positive blood cultures for group A streptococcus (33 medical records were available). Yearly incidence and clinical features of cases; microbiological features of isolated organisms. There was a significant increase (P = .01) in the incidence of group A streptococcus bacteremia over an 11-year period, with 14 (41%) of these cases occurring in 1989 and 1990. Patients had a rapidly progressing illness, usually without preceding pharyngitis. The prominent M and T types were 1 (4) and 12 (4). Eleven (73%) of the 15 strains produced pyrogenic exotoxin B that significantly correlated with production of proteinase. There appears to be an increase in group A streptococcus bacteremia in children that is associated with a strain phenotype that suggests a change in organism virulence.