Risk of bacteremia in young children with pneumonia treated as outpatients

Background: Blood cultures are often obtained as part of the evaluation of children with pneumonia. There are few data regarding the risk of bacteremia with pneumonia in children since introduction of the Haemophilus influenzae type b vaccine. Objective: To evaluate the risk of bacteremia in young children with pneumonia who were treated as outpatients. Methods: A retrospective cohort study of 580 children aged 2 to 24 months who were evaluated by blood culture in a tertiary care children's hospital emergency department between February 1, 1993, and May 31, 1996, and discharged with the diagnosis of pneumonia. Results: The mean patient age was 14.1 months; 339 patients (58.4%) were boys. Thirty-eight patients (6.6%) reported the use of oral antibiotics before initial emergency department evaluation. The prevalence of bacteremia was 1.6% (95% confidence interval, 0.7%-2.9%). Streptococcus pneumoniae was the causative organism in all 9 cases. The serotype was available for 8 of 9 cases. Six (75%) of 8 cases of S pneumoniae bacteremia were caused by serotypes included in the current heptavalent pneumococcal conjugate vaccine, which was not available at the time of this study. The contamination rate was 1.9% (95% confidence interval, 1.0%-3.4%). The mean ± SD time to blood culture positive for organisms in a continuously monitored system was significantly shorter for pathogens (13.9±1.3 hours) than for contaminants (21.2±6.1 hours; P=.01). Conclusions: Children aged 2 to 24 months with pneumonia who are treated as outpatients are at low risk of bacteremia. Widespread use of the pneumococcal conjugate vaccine may further decrease the incidence of bacteremia in this population.