[Comparison of the in vitro activity of ceftazidime: in culture, in serum and in combination with granulocytes].

The bactericidal activity of ceftazidime against 5 serum resistant Staphylococcus epidermidis and 5 serum sensitive Pseudomonas aeruginosa strains was compared in Mueller-Hinton broth and normal human serum. Except for the first 4 hours incubation time ceftazidime was less active in serum as compared to broth against the serum resistant staphylococci at subinhibitory concentrations. Against the serum sensitive Pseudomonas aeruginosa strains the in vitro activity of ceftazidime in serum was significantly higher than in broth at all concentrations investigated. In vitro activity of ceftazidime was best in combination with leukocytes and serum against a Staphylococcus aureus and a Pseudomonas aeruginosa strain. Leukocytes in serum enhanced the bactericidal activity of ceftazidime against a Pseudomonas aeruginosa strain already at 1/4 MIC, which could only slightly be improved at 1 MIC, but not at 4 MIC.