Comparative in vitro activity of cefpiramide, a new parenteral cephalosporin.

The in vitro activity of cefpiramide was compared with that of nine other cephalosporins by determining the MIC values by means of an agar dilution method for 300 representative clinical isolates of nonfastidious bacteria. Cefpiramide had a broad-spectrum of activity, similar to that of the third-generation cephalosporins. As judged by the MIC50 and the MIC90 values, cefpiramide was one of the most active cephalosporins against Pseudomonas aeruginosa (MIC50 2.9 micrograms/ml, MIC90 64 micrograms/ml), staphylococci (MIC50 1.2 micrograms/ml, MIC90 10 micrograms/ml) and Enterococcus faecalis (MIC50 13 micrograms/ml, MIC90 43 micrograms/ml). Cefpiramide had moderate activity against Enterobacteriaceae (MIC50 4 micrograms/ml, MIC90 108 micrograms/ml), comparable to that of the older second-generation cephalosporins. Ticarcillin-resistant strains of gram-negative rods were inhibited by higher concentrations of cefpiramide than ticarcillin-susceptible strains.