Antibiotic susceptibility of Streptococcus pneumoniae isolates from paediatric patients.

We studied 91 strains of Streptococcus pneumoniae isolated in the Children's and Maternity Hospital San Juan de Dios of Barcelona, Spain, from July 1984 to June 1986. All strains were recovered from miscellaneous sites in different patients. We tested their susceptibility to 14 antimicrobial agents: penicillin, gentamicin, chloramphenicol, tetracycline, co-trimoxazole, erythromycin, vancomycin, rifampicin, cephalothin, cefaclor and cefotaxime. In addition, for 56 of the strains, cefonicid, cefoxitin and imipenem were included. We found many strains with decreased penicillin susceptibility (52.8%). Among the beta-lactam antibiotics tested, cefotaxime and imipenem showed the lowest MIC (less than or equal to 1 mg/l). Only 5.5% of the strains showed resistance to erythromycin, and all were susceptible to vancomycin and rifampicin. Tetracycline and co-trimoxazole were the antimicrobials with the highest prevalence of resistance (72.5% and 67%, respectively). Our isolates were distributed in 21 serotypes, serotype 23 being the most frequent among strains with decreased penicillin susceptibility (50%).