Efficacy of different dosing schedules of tobramycin for treating a murine Klebsiella pneumoniae bronchopneumonia.

The efficacy of different dosing schedules of tobramycin for treating a murine Klebsiella bronchopneumonia was compared. Therapeutic efficacy depended upon dosing intervals. In mice treated for four days with a daily dose of 48 mg/kg, dosing intervals of 4 and 8 h allowed cure of 10/10 animals, whereas dosing intervals of 12 and 24 h yielded survival rates of only 6/10 (P less than 0.05) and 2/10 (P less than 0.01) respectively. Although observed in vitro, a post-antibiotic effect of tobramycin against K. pneumoniae was unlikely in vivo since residual concentrations of tobramycin were found in the lung tissue 12 h after dosing, when efficacy starts to decrease. Efficacy also depended to some extent upon the duration of therapy.