Comparison of the susceptibility of Pseudomonas aeruginosa and Escherichia coli, isolated from clinical specimens to ticarcillin, ticarcillin/clavulanic acid and piperacillin/tazobactam

In this study, the susceptibilities of 50 Pseudomonas aeruginosa and 50 Escherichia coli strains isolated from clinical specimens, against ticarcillin, ticarcillin/clavulanic acid and piperacillin/tazobactam were investigated by disk diffusion method. Of pseudomonas aeruginosa isolates, 54% were found to be sensitive to ticarcillin, 74% to ticarcillin/clavulanic acid, whereas 24% of Escherichia coli isolates were sensitive to ticarcillin (susceptible + moderately susceptible), and 94% to ticarcillin/clavulanic acid. It was determined that 23% of P. aeruginosa and 4% of E. coli isolates brought about a zone diameter equal to or below 15 mm against piperacillin/tazobactam. As a result, P. aeruginosa and E. coli isolates were found to be susceptible to both of the beta-lactam/beta-lactamase inhibitor combinations.