Enoxacin: in-vitro and animal evaluation as a parenteral and oral agent against hospital bacterial isolates

Enoxacin was evaluated in in-vitro tests and in studies of effectiveness and blood concentrations in the mouse. Enoxacin was active against both susceptible and multircsistant hospital isolates of Enterobacteriaceae, Pseudomonas aeruginosa, Haemophilus influenzae, Neisseria gonorrhoea and staphylococci. Less susceptible were streptococci and anaerobes. Of nine quinolones tested, only norfloxacin was equivalent in vitro. The MBCs of enoxacin were one- to two fold greater than the MICs, and enoxacin was rapidly bactericidal. No single-step resistant mutants could be detected at 10mg/l against large inocula and six to 11 steps were required for selection of resistant clones. In systemic mouse infections, enoxacin was effective in a single oral or subcutaneous dose against one strain each of Enterobacter cloacae, Escherichia coli, Klebsitlla pneumoniae, Providencia rettgeri and Ps. aeruginosa, and two Staphylococcus aureus strains. Single oral and subcutaneous enoxacin doses (50 mg/kg) gave peak mouse blood levels of 4·9 and 9·5 mg/l and an elimination half-life of 1·8 h.