Constancy of distribution of serogroups of invasive pneumococcal isolates among children: experience during 4 decades.

Serogroups of pneumococci that caused bacteremia or meningitis in children were examined from 1981 through 1998 at Boston City Hospital/Boston Medical Center. There were 410 episodes of pneumococcal bacteremia (13--36 cases per year), of which 14 occurred in human immunodeficiency virus (HIV)--infected children and 9 occurred in children with sickle-cell disease. The 7 most common serogroups were 14 (30.7% of isolates), 19 (11.7%), 6 (11%), 18 (10.7%), 9 (7.6%), 23 (7.3%), and 4 (5.6%). The rate of episodes due to serogroups 4, 6, 9, 14, 18, 19, and 23 ranged from 80% to 91.9% during the study period. The rate of episodes due to serogroups 4, 6, 14, 18, 19, and 23 was 84.6% among patients with HIV infection, 100% among patients with sickle-cell disease, and 94.1% among the 18 patients for whom cultures of CSF specimens revealed pneumococcal meningitis. The results demonstrate that type 14 was the dominant pneumococcal serogroup responsible for invasive disease throughout the 18-year study period and that serogroup distribution overall remained constant. A comparison of these findings with historical pediatric data from our institution showed serogroup stability dating back to 1957.