Serotypes of Streptococcus pneumoniae causing disease.

Serotypes of Streptococcus pneumoniae from 525 infected children were examined over a four-year period. Type distribution was similar among 84 cases of bacteremia and 30 cases of meningitis, with types 6, 14, and 18 accounting for half of the illnesses. In contrast, half of 396 episodes of otitis media were caused by three other types, 19, 23, and 3. Four of eight fatalities were due to type 6. Carrier strains isolated from children had a distribution of types similar to that of the otitis media collection. Adult patients had fewer of the types that caused disease in children. Most childhood infections (80%) occurred in children less than or equal to 24 months of age; no relationship between age and infecting serotype was noted. There were no seasonal trends in type distribution.