Abstract 831 Poster Session I, Saturday, 5/1 (poster 279)

Children with SCD are at increased risk for Pnc infections. We reviewed cases of invasive Pnc infection in children with SCD admitted to three hospitals in Atlanta over a four year period (1994-1998), including only children with hg SS. Using the Georgia Emerging Infections Program database, children with SCD and invasive Pnc disease were compared to other Atlanta children of black race who developed invasive Pnc disease during this same time period. Isolates were tested at the CDC for antimicrobial susceptibility using broth microdilution according to NCCLS methods and for serotype using Quellung reaction. We compared penicillin susceptibility results and serotype using stratified analysis controlling for age. We identified 30 cases of children with Pnc and hg SS SCD; all were <11 years of age. Two patients had recurrent infections within 2 months; these patients were included only once in the analysis. We identified 631 children without known SCD and invasive Pnc infection in this age range for whom isolates were available. Overall, 35.9% of children had infections due to penicillin-nonsusceptible Pnc; the most commonly identified serotypes were 14 (n=209, 32.5%), 6B (n=82, 12.8%), 19F (n=70, 10.9%), and 23F (n=66, 10.3%). Controlling for age, children with SCD were significantly more likely than other black children to have isolates that were non-susceptible to penicillin (MIC=/> 0.1 µg/ml, summary RR 1.7, 95% CI 1.2-2.4, p=.02) and to have an infection with serotype 23F (summary RR 3.2, 95% CI 1.6-6.2, p=.003), a serotype commonly resistant to penicillin and other antimicrobial agents. (Table)

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This data suggests that children with SCD are more likely to be infected with Pnc 23F isolates than other children. Most of these isolates are penicillin resistant. The mechanism for Pnc 23F selection in children with SCD may be due to pressure from penicillin prophylaxis, spread of a resistant clone in the sickle cell population and/or immune predisposition. Insuring that new vaccines protect against serotype 23F in children with SCD may be particularly important.