IN-VITRO ACTIVITY OF SPARFLOXACIN AGAINST METHICILLIN-RESISTANT STAPHYLOCOCCI

The antimicrobial activity of sparfloxacin (GAS 110871-86-8) against 1 54 clinical isolates of methicillin-resistant staphylococci was invest igated and compared with that of 6 other fluoroquinolones. The isolate s consisted of 100 methicillin-resistant Staphylococcus aureus (MRSA), 29 Staphylococcus epidermidis (MRSE) and 25 other coagulase-negative staphylococci (CNS). Sparfloxacin was more active than ciprofloxacin a nd the other fluoroquinolones against all strains tested. The MIC(90) of sparfloxacin against the 100 isolates of Staphylococcus aureus was 8 mg/l, while that of ciprofloxacin was greater than or equal to 64 mg /l. Moreover, ciprofloxacin-susceptible MRSA isolates were inhibited b y sparfloxacin at a concentration of less than or equal to 0.06 mg/l. The other quinolones had an MIC(90) ranging from 0.5 mg/l to 4 mg/l ag ainst ciprofloxacin-susceptile MRSA. Similar results were obtained for the MRSE and CNS isolates tested. As many as 90% of the ciprofloxacin -susceptible microorganisms were inhibited at a concentration of less than or equal to 0.06 mg/l os 0.125 mg/l of sparfloxacin. The MIC(90) of sparfloxacin against ciprofloxacin-resistant CNS and MRSE were 4 mg /l and 8 mg/l, respectively. Sparfloxacin was clearly more active than any of the other quinolones against all species tested, although high er concentrations were needed to inhibit ciprofloxacin-resistant staph ylococci.