Antipneumococcal activity of MEN 10700, a new penem, compared with other compounds, by MIC and time-kill kinetics.

The antipneumococcal activity of MEN 10700 was compared with those of nine other compounds by MIC and time-kill kinetics. MIC90s (mg/L) of 202 penicillin-susceptible, -intermediate and -resistant pneumococci were: 0.06, 1.0 and 2.0 (MEN 10700); 0.06, 0.5-1.0 and 2.0 (amoxycillin +/- clavulanate); 0.06, 0.5 and 4.0 (cefotaxime); 0.125, 0.5 and 2.0 (cefepime); 0.016, 0.125 and 0.25 (imipenem); 0.03, 0.5 and 1.0 (meropenem); 2.0 (ciprofloxacin); 0.125, >64.0 and >64.0 (clarithromycin); and 0.5 (vancomycin). Time-kill kinetics showed that MEN 10700, at 4 x MIC, was bactericidal for all 12 isolates tested at 4 x MIC. Kinetics of other beta-lactams were similar to those of MEN 10700, relative to MICs. Ciprofloxacin, at 4 x MIC, was uniformly bactericidal after 24 h. Clarithromycin exhibited slow kill kinetics, after 24 h. Vancomycin was bactericidal against 11/12 isolates at 2 x MIC after 24 h.