In-vitro activity of enoxacin (CI-919), a new quinoline derivative, compared with that of other antimicrobial agents

Abstract
The in-vitro activity of enoxacin (CI-919), a new synthetic quinoline derivative was compared with that of three other quinolines ofloxacin, norfloxacin and nalidixic acid. In addition β-lactams and gentamicin were also included when appropriate. The MICs of enoxacin for 90% of Escherichia coli, Klebsiella spp., Enterobacter spp., Proteus spp., Providencia stuartii, Pseudomonas aeruginosa and Staphylococcus aureus were less than 4 mg/l, for Haemophilus influenzae less than 0.25 mg/1 and Neisseria gonorrhoeae less than 0.03 mg/1. Bacteroides fragilis and streptococci (including Streptococcus pneumoniae) were less susceptible, MIC90, 16 mg/1. Against many of the common Enterobacteriaceae enoxacin displayed a similar degree of activity as gentamicin. Gentamicin-resistant strains of common bacterial pathogens were susceptible to enoxacin as were methicillin-resistant Staph. aureus. The protein binding of enoxacin (concentration 5 mg/1) was 18%.