Bacteriostatic and bactericidal activity of penicillins at constant and variable concentrations.

Temocillin, the first beta-lactamase stable penicillin which is active against Gram-negative bacteria, was shown to be much more potent than ampicillin, piperacillin and mezlocillin against most species of Enterobacteriaceae. All isolates of Escherichia coli producing TEM 1, TEM 2 or OXA 1 beta-lactamases were sensitive to temocillin. When the prolonged kinetics of elimination of temocillin were simulated in an in vitro system, more rapid killing and less regrowth occurred as compared with penicillins with more rapid elimination.