IN-VITRO AND IN-VIVO ANTIBACTERIAL ACTIVITIES OF CS-940, A NEW FLUOROQUINOLONE, AGAINST ISOLATES FROM PATIENTS WITH RESPIRATORY-INFECTIONS

We compared the in vivo and in vitro activities of CS-940, a new fluor oquinolone, with those of a group of other drugs. The activities of CS -940 against gram-positive cocci and gram-negative rods, including met hicillin-susceptible Staphylococcus aureus and penicillin-resistant St reptococcus pneumoniae, were comparable to those of tosufloxacin, with MICs at which 90% of the strains were inhibited (MIC(90)s) of 0.5 mu g/ml or less. Against methicillin-resistant S. aureus, CS-940 was as a ctive as tosufloxacin, with a MIC90 of 16 mu g/ml. The efficacy of CS- 940 against murine respiratory infections due to S. pneumoniae or Haem ophilus influenzae was better than those of tosufloxacin and sparfloxa cin. The efficacy of oral doses of CS-940 reflected not only potent in vitro activity but also a high transmigration ratio from the bloodstr eam to lung tissues.