Clinical experience with tobramycin in the treatment of infections due to gram-negative bacilli.

Tobramycin, a new aminocyclitol antimicrobial agent, was administered parenterally to 28 patients infected with gram-negative bacilli. The dosage was 1.5 mg/kg every 8 hours, except in patients with renal insufficiency in whom the dosage interval was 10 times the serum creatinine in hours. Serum levels after intramuscular administration were 3.9 +/- 1.6 mug/ml and 1.0 +/- 0.7 mug/ml at 2 and 8 hours, respectively. Serum levels after intravenous administration were 4.6 +/- 0.5 mug/ml, 2.3 +/- 0.6 mug/ml, and 0.6 +/- 0.8 mug/ml at 15 minutes, 1 hour, and 8 hours, respectively. Clinical isolates included 21 of Pseudomonas aeruginosa, 6 of Klebsiella pneumoniae, 2 of Serratia marcescens, and also isolates of E. coli, Proteus mirabilis, and Enterobacter. The minimum inhibitory concentrations (MICs) of tobramycin, gentamicin, sisomicin, and amikacin were determined for these organisms. Clinical results included 18 cures, 3 improvements, 2 indeterminates, and 6 failures. Minimal hepatic and renal toxicity was observed.