Streptococcus pneumoniae is, even now, important pathogen of respiratory infections. It annually forms 20 to 30 per cent of the causative bacteria of respiratory infections determined by our quantitative sputum culture method. And recently resistant strains against some antibiotics were reported. Therefore 64 strains of respiratory pathogenic Streptococcus pneumoniae isolated more than 107ml from sputa were studied on the susceptibility to 17 antibacterial agents and serotype, with following results :
1. There was no noticeable resistant strain against penicillins. Antibacterial activities of penicillins were in order Amoxycillin≅PC-904≥Benzylpenicillin≅Ampicillin≅Piperacillin>Ticarcillin.
2. There was no resistant strains against cephalosporins. Antibacterial activities were Cephaloridine >Cefazolin>Cefoxitin<Cephalexin.
3. Resistant strains against Chloramphenicol, Thiamphenicol and Doxycycline were respectively 57.4%, 57.8% and 62.3%. 52.6% of 64 strains were resistant against all of them.
4. There was no resistant strain against Clindamycin, Erythromycin and Josamycin. Antibacterial activities were Clindamycin>Erythromycin≥Josamycin.
5. Serotypes of 54 strains were examined, and only 5 strains were type III and the others were non-typable.
