Abstract

Resistance to penicillin for Streptococcus pneumoniae, differs from region to region. This study was planned to determine intermediate and high-level resistance rates to penicillin in our local area. Eighty three pneu - mococcal strains were isolated from patients with lower respiratory infections who were admitted to Izmir Training and Research Hospital For Thoracic Medicine and Surgery between November 1999 and May 2001. Penicillin resistant strains were determined by disc diffusion method using oxacillin discs. Agar dila - tion method was performed to penicillin resistance levels of pneumococcus strains. All tests were performed according to NCCLS standards. Sixteen (19.2%) strains were resistant to penicillin. In 12 (14.4%) strains, intermediate levels of resistance was found (MIC 0.12-1 µg/ml). High levels of resistance for penicillin (MIC ≥2 µg/ml) was detected in 4 (4.8%) strains. These findings suggest that penicillin is still the major antibiotic for empiric therapy in pneumococcal respiratory infections in our region. The MIC values for penicillin for pneumococcal strains has to be detected in order to understand the spreading of resistant strains under suitable circumstances.