Risk factors and course of illness among children with invasive penicillin-resistant Streptococcus pneumoniae

Objectives. To assess differences in risk factors, clinical presentation, a nd course of illness between factors children infected with penicillin-sens itive and drug-resistant Streptococcus pneumoniae (DRSP). Design. A retrospective cohort study conducted in Uruguay and Argentina usi ng information from a hospital-based surveillance system. Hospitalized chil dren 5 years of age and younger who had S pneumoniae isolated from a normal ly sterile site between June 1993 and October 1996 were eligible. Hospital records were linked with surveillance data. Both stratified univariate anal ysis and logistic regression was completed. Results. Of the 380 children eligible for the study, 274 records (72%) were available for review. Ninety-nine children (36%) had DRSP; 46 showed inter mediate susceptibility (minimum inhibitory concentration, 0.12-1.0 mu g/mL) and 53 showed high-level resistance (minimum inhibitory concentration grea ter than or equal to 2.0 mu g/mL). Children with meningitis were less likel y to have DRSP than those with other forms of invasive disease (relative ri sk = 0.5; 95% confidence interval [CI], 0.2-0.9). Risk factors associated w ith DRSP were use of penicillin or ampicillin in the 3 months before illnes s (odds ratio = 2.9; 95% CI, 1.5-5.7) and possession of private medical cov erage (odds ratio = 2.4; 95% CI, 1.2-5.0). Response to therapy, including r esponse to penicillin or ampicillin among children with nonmeningeal invasi ve disease, course of illness, and clinical outcome did not differ signific antly between children infected with penicillin-susceptible or penicillin-r esistant isolates. Conclusion. In this study, previous use of penicillin or ampicillin and pri vate medical coverage were associated with having DRSP. Children with nonme ningeal invasive disease responded equally well to penicillin regardless of the penicillin susceptibility of their pneumococcal isolate.