Streptococcus pneumoniae is part of the normal flora but is also responsible for causing many invasive diseases such as pneumonia, meningitis, and sepsis in addition to noninvasive diseases such as otitis in children. Multi-drug resistant strains has raised a lot of concern worldwide and thus the importance of prevention has been emphasized. We have analyzed the current serotypes and antibiotic sensitivity of each serotype as a baseline study to estimate the efficacy of the pneumococcal vaccine in Korean children.

One hundred sixteen cases of pneumococcus cultured at Yonsei Medical Center from September 2001 to January 2003 were analyzed. The serotyping was done with the Quellung reaction and penicillin resistance was tested using the oxacillin disc diffusion method.

Pneumococcus were cultured from the sputum in 76 cases(65.5%), from the blood in 13 cases(11.2%), from the ear discharge in 12 cases(10.3%), from the throat in 7 cases(6.0%), from the nasal cavity in 2 cases(1.7%), and one case(0.9%) each from the cerebrospinal fluid, eye discharge, peritoneal fluid, post-operational wound, brain abscess, and catheter tip. Serotyping was possible with 98 cases and the following serotypes were found; 15 cases of type 19F(15.3%), 11 cases of 19A(11.2%), 8 cases of 11A(8.2%), 7 cases each of 6A, 14 and 3(7.1%), 6 cases each of 35, 6B and 23F(6.1%). Eighty two cases(70.7%) out of 116 cases were penicillin resistant and serotypes 19F, 19A, 11A, 23F, 6A, 9V constituted the majority, 48 cases(59.8%). These serotypes showed resistance to cotrimoxazole (74.4%), tetracycline(69.5%), and erythromycin(90.3%) as well. In the 22 cases cultured from children, 19A and 19F were found in 25.0%, 6A, 6B, and 23F in 10.0%, 11A, 14, 19, and 29 in 5.0%. Fifty percent(10/20) of the clinical isolates were represented in the current 7 valent pneumococcal protein conjugate vaccine, and 85%(17/20) when the cross-reacting serotypes were included. Penicillin resistance was found in 86.4%(19/22).

The percentage of serotypes included in the 7 valent pneumococcal protein conjugate vaccine found in our study was 40.8% which was less than other prior studies. In anticipation of a change of pneumococcal serotypes, a nationwide multicenter study is needed before the initiation of pneumococcal vaccines in Korea.