Serotypes and antimicrobial susceptibilities of Streptococcus pneumoniae isolated from hospitalized patients in Thailand

Two hundred seven Streptococcus pneumoniae isolates were obtained from patients admitted to Siriraj Hospital. One hundred two, and 105 isolates were from sterile sites and non-sterile sites, respectively. They were serotyped by Quellung reaction with specific antisera from Statens Serum Institut; 81.6% of these pneumococci were typeable. These serotypes were included in the 23-valent pneumococcal polysaccharide vaccine. The five most common serotypes were serotype 6 (22.5%), followed by serotype 23 (18.9%), serotype 19 (16.6%), serotype 3 (7.7%) and serotype 11 (5.3%). Among typeable pneumococci (169 isolates), 52.7% were from sterile sites and 47.3% were from non-sterile sites. Serotypes 6, 23 and 19 were the predominant serotypes isolated from sterile sites. Of the 9 drugs tested, pneumococcal isolates were sensitive to ofloxacin (99%), ciprofloxacin (81.5%), meropenem (80%), imipenem (66.5%), ceftriaxone (65%), cefotaxime (63%), erythromycin (58%), penicillin (48%), and trimethoprim-sulfamethoxazole (34.5%).