[Comparative in vitro activity of ampicillin, cefoperazone, their combinations with sulbactam and other antibiotics with respect to staphylococci and pneumococci].

Antibiotic susceptibility of 225 Staphylococcus strains and 42 Pneumococcus strains was assayed with the method of serial microdilutions. Methicillin resistant Staphylococcus strains (S. aureus and coagulase negative strains) were characterized by high susceptibility to cephalosporins and ampicillin + sulbactam combination, as well as to ciprofloxacin, rifampicin and vancomycin (70 to 100 per cent of the susceptible strains). Less than 50 per cent of the strains was susceptible to erythromycin. The methicillin resistant Staphylococcus strains preserved their high susceptibility to vancomycin and rifampicin (the coagulase negative strains also preserved their susceptibility to ciprofloxacin). Four Pneumococcus strains with the intermediate resistance to benzylpenicillin were isolated (for 9.6 per cent of the strains the MIC was 0.12 to 1.0 micrograms/ml). The growth of 2 out of these 4 strains was inhibited by the ampicillin + sulbactam combination in a concentration of less than 0.5 micrograms/ml and by cefotaxime and the cefoperazone + sulbactam combination in a concentration of less than 1.0 micrograms/ml. The growth of the other 2 strains was inhibited by betalactams in concentrations higher than the above mentioned.