Comparative study of new benzenesulphonamide fluoroquinolones structurallyrelated to ciprofloxacin against selected ciprofloxacin-susceptible and -resistant Gram-positive cocci

The in vitro activities of benzenesulphonamide fluoroquinolones (BSFQs) I-I II, new fluoroquinolones with a p-substituted benzenesulphonyl moiety attac hed to the C-7 piperazinyl ring of ciprofloxacin, were assessed in comparis on with those of N-sulfanilylpiperazinyl fluoroquinolone (NSFQ)-105 and cip rofloxacin for 133 Gram-positive clinical isolates. NSFQ-105 and BSFQ-I wer e the most active drugs. They were 16- to 64-fold more active than ciproflo xacin against Staphylococcus aureus, Staphylococcus epidermidis, Enterococc us faecalis, including ciprofloxacin-resistant strains, and Streptococcus p neumoniae (eight- to 32-fold). A high degree of correlation was found betwe en the MICs of the new compounds and ciprofloxacin for Staphylococcus spp. and E. faecalis. Staphylococci and enterococci exhibit cross-resistance to BSFQs and ciprofloxacin.