Antibacterial effects of ticarcillin/clavulanic acid in animal models of infection.

The therapeutic effects produced by ticarcillin plus clavulanic acid were compared with those of ticarcillin and clavulanic acid separately against infections in the mouse caused by beta-lactamase-producing bacteria. The infections studied included a pneumonia model, a local tissue infection and pyelonephritis. The distribution of ticarcillin and clavulanic acid in infected animals was evaluated by measurement of the concentrations of the substances present at sites of infection. The results showed that both ticarcillin and clavulanic acid were well-distributed in the mouse and at the doses employed were present at the sites of infection at concentrations of the same order as those obtained in man after administration of ticarcillin/clavulanic acid formulations (Timentin). The protection of ticarcillin by clavulanic acid from inactivation by the beta-lactamases produced in vivo by Bacteroides fragilis, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa was demonstrated by the pronounced bactericidal effects produced by the ticarcillin/clavulanic acid combination against the ticarcillin-refractory infections studied.