Comparative activities of N-formimidoyl thienamycin, ticarcillin, and tobramycin against experimental Pseudomonas aeruginosa pneumonia.

The therapeutic efficacies of disodium ticarcillin, tobramycin sulfate, and N-formimidoyl thienamycin (MK0787) were compared in guinea pigs with experimentally induced Pseudomonas aeruginosa pneumonia. Survival rates were 35% for ticarcillin, 80% for tobramycin, and 75% for N-formimidoyl thienamycin. Numbers of viable Pseudomonas organisms in lungs approximately 3 h after the first dose of drug were nearly 10-fold fewer in tobramycin- or N-formimidoyl thienamycin-treated animals than in ticarcillin-treated animals. Our data suggest that N-formimidoyl thienamycin may have therapeutic efficacy against respiratory infections with P. aeruginosa equivalent to that of tobramycin.