In vitro activity of a new 'higher-lactam' antibacterial agent LY 193239.

In vitro activity of the new bicyclic pyrazolidinone LY 193239 (Eli Lilly) was evaluated against 52 clinical isolates of Haemophilus influenzae (4 were beta-lactamase producers), 32 Enterococcus faecalis, 14 Neisseria gonorrhoeae (1 beta-lactamase-positive) and 19 Neisseria meningitidis. Activity was best against Neisseria spp. and H. influenzae, including penicillinase-producing strains. Results of the time-kill study against a non-enzyme-mediated penicillin resistant strain of N. meningitidis indicate that exposure to an antibacterial concentration four times the minimal inhibitory concentration was bactericidal. E. faecalis was insensitive.