Objectives: The purpose of the study is to evaluate the incidence, spectrum of clinical manifestations and outcome of invasive pneumococcal disease (IPD) in children in Chiba prefecture, Japan.
Methods: To determine the precise incidence of IPD in Chiba prefecture, we implemented a retrospective survey of the period from 2003 to 2005. A written questionnaire was sent to 45 hospitals that have pediatric wards, and information was obtained from all hospitals. The questionnaire included the clinical diagnosis, patient's age, underlying disease, prognosis and antimicrobial susceptibility of the isolated strains.
Results: During the 3 study years, 130 patients were diagnosed with IPD. The mean annual incidence rates of IPD among children <2 and <5 years were 19.5-23.8 and 12.6-13.8 per 100,000, respectively. Among 130 patients with systemic infection, 66 patients had bacteremia, 39 had pneumonia and 16 had meningitis. Five patients had neurological sequelae and 2 patients died. Seventy-four out of 115 isolates (64.3%) exhibited resistance to penicillin G.
Conclusions: The annual incidence of pediatric IPD has remained constant during the study period. Two-third of isolated strains were at least partially resistant to penicillin G. Establishment of appropriate antibiotic therapy against IPD due to penicillin-resistant strains and the introduction of pneumococcal conjugate vaccines are emergent issues in Japan.