To characterize the epidemiology and clinical features of invasive pneumococcal infections in Korean children.

One hundred ninety four cases of invasive pneumococcal infections diagnosed at the Seoul National University Children's Hospital from October 1985 to December 2003 were analysed retrospectively. All isolates were screened for resistance to penicillin by oxacillin disc diffusion test. Serotypes were determined for 125 isolates.

The types of infection were bacteremia without focus 84/194(43%), meningitis 36/194(19%), pneumonia with bacteremia 36/194(19%), peritonitis 24/194(12%), other focal infections 3/194(2%). Fifty seven percent(110/194) of the episodes developed in the immunocompromised and 20%(37/194) were nosocomially acquired. The patients younger than 2 years of age was 60% in the immunocompetent patients and 25% in the immunocompromised patients. The overall case fatality rate was 7%. All the isolates by 1988 were susceptible to penicillin screened by oxacillin disk. Penicillin resistance was first detected in 1989(20%), and then increased rapidly; 89% in 1995, 69% in 1996, and 80~100% thereafter. The seven most frequently isolated serotypes were 23F, 19F, 14, 6B, 6A, 9V and 19A, which accounted for 70% of total isolates.

S. pneumoniaeis an important cause of morbidity and mortality in children. Invasive infections caused by S. pneumoniae most often occurred in infants and young children, while they are frequent in older immunocompromised children as well. This is the largest case series on invasive pneumococcal infections in Korean children.