[Comparative activity of cefsulodin on Pseudomonas aeruginosa, Acinetobacter and Enterobacteriaceae (author's...

Cefsulodin, a new semi-synthetic cephalosporin, is characterized by its activity against P. aeruginosa. In this study the authors compared this new molecule with other four betalactamines, carbenicillin, ticarcillin, azlocillin and mezlocillin, and two aminoglycosides, amikacin and netilmicin. Two hundred and forty five strains studied were 100 Pseudomonas aeruginosa, 20 Acinetobacter, 42 Proteus, 21 Serratia, 22 Enterobacter, 20 Klebsiella and 20 E. coli. One hundred twenty strains of these showed carbenicillin resistant phenotype. MIC were determined by the agar dilution method. Cefsulodin was only active on Pseudomonas aeruginosa. MICs were at least 16 mg/l in the other species. On carbenicillin susceptible P. aeruginosa strains, the average MIC of cefsulodin, amikacin and netilmicin was 1 mg/l, and MICs of azlocillin, mezlocillin, ticarcillin and carbenicillin were 4-8 mg/l, 8 mg/l, 16 mg/l and 32 mg/l, respectively. On carbenicillin resistant P. aeruginosa, ticarcillin and mezlocillin were not effective and MICs of azlocillin and cefsulodin were 16 mg/l and 4-8 mg/l, respectively. However, MICs were between 64 and 128 mg/l in 20 p. cent of carbenicillin resistant strains.