In-vitro activities of ciprofloxacin, levofloxacin, lomefloxacin, ofloxacin, pefloxacin, sparfloxacin and trovafloxacin against Gram-positive and Gram-negative pathogens from respiratory tract infections

Trovafloxacin, sparfloxacin, ciprofloxacin and levofloxacin were equally active against Moraxella catarrhalis, Haemophilus influenzae, Legionella pneumophila, Klebsiella pneumoniae, Enterobacter cloacae and Serratia marcescens. Ciprofloxacin was the most active compound against Pseudomonas aeruginosa (MIC90 = 1 mg/L), followed by trovafloxacin (MIC90 = 4 mg/L). Trovafloxacin was twice as active as sparfloxacin against Streptococcus pyogenes (MIC90 = 0.12 mg/L), Streptococcus pneumoniae (MIC90 = 0.12 mg/L) and Staphylococcus aureus (MIC90 = 0.06 mg/L) (except quinolone-resistant, methicillin-resistant S. aureus, for which the MIC90 was 8 mg/L). Trovafloxacin was the most active compound against Enterococcus faecalis: 80% of strains were susceptible to 0.25 mg/L. There was complete cross-resistance between all fluoroquinolones.