IN-VITRO AND IN-VIVO EVALUATIONS OF LB20304, A NEW FLUORONAPHTHYRIDONE

In vitro activity of LB20304 against 1,231 clinical isolates was evalu ated and compared with those of ciprofloxacin, sparfloxacin, lomefloxa cin, and ofloxacin. LB20301 demonstrated the most potent activity agai nst gram-positive bacteria. It was 32- to 64-fold more active than cip rofloxacin against methicillin-susceptible Staphylococcus aureus, meth icillin-resistant S. aureus, methicillin-resistant Staphylococcus epid ermidis, and Streptococcus pneumoniae (penicillin G resistant). LB2030 1 was also highly active against most members of the family Enterobact eriaceae. Its activity was more potent than those of sparfloxacin, ofl oxacin, and lomefloxacin and comparable to that of ciprofloxacin. The protective activities of LB20301 against systemic infections caused by gram-positive bacteria in mice were superior to those of ciprofloxaci n and sparfloxacin. Against infections by grim-negative bacteria, LB20 304 was slightly less active than ciprofloxacin.