In-vitro bacterial killing kinetics of ticarcillin/clavulanic acid

An in-vitro model was developed to study the rates of killing by ticarcillin/clavulanic acid combinations of various beta-lactamase producing, ticarcillin resistant, logarithmic phase clinical isolates. Killing, defined as a 3 log reduction, was dependent on the organism, the concentration of clavulanic acid and the duration of exposure. For most isolates studied an optimum period of exposure to and concentration of clavulanic acid could be defined. Certain test strains showed optimum response to readily attainable in-vivo concentrations of clavulanic acid while other strains, although sensitive by MIC data showed a poor response. The clinical implications of this are discussed.