Inhibitory and bactericidal activity of cefpirome and cefotaxime against blood culture isolates

Using a broth microtiter dilution method, minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) were determined for the aminothiazolyl cephalosporins cefpirome and cefotaxime against 436 blood culture isolates. At concentrations of less than or equal to 16 mg/l, cefpirome inhibited 82.3% of the isolates and cefotaxime 66.5%. At the same concentrations, cefpirome killed 60.0% of the isolates and cefotaxime 46.7%. Whereas the MIC values indicated a far better activity of cefpirome than cefotaxime against oxacillin-resistant Staphylococcus aureus, Enterococci and Pseudomonas aeruginosa, the MBC values showed a poor activity of both drugs against these strains. By comparison, cefpirome was the more active agent, covering a similar spectrum to that of cefotaxime with a slight additional activity against oxacillin-susceptible S. aureus and Staphylococcus epidermidis.