In vitro activity of carumonam (RO 17-2301) and twelve other antimicrobials against clinical isolates of Pseudomonas aeruginosa.

Minimal inhibitory concentrations of the monobactam carumonam (RO 17-2301) and twelve other antimicrobials were determined using agar dilution against 140 recent non-replicate clinical isolates of Pseudomonas aeruginosa. The most active drugs were ciprofloxacin, amikacin, imipenem and ceftazidime, inhibiting 96, 91, 90 and 86 percent of the strains, respectively, at or below the susceptibility threshold. The monobactams carumonam and aztreonam were active against 78 and 65 percent of the strains, respectively. Tobramycin inhibited 68 percent of the strains, and gentamicin and netilmicin 50 and 21 percent, respectively. Analysis of correlation coefficients revealed a low correlation between imipenem and the other beta-lactams and a remarkably good correlation between the beta-lactams (excepting imipenem) and the aminoglycosides.