Purpose : To evaluate the spectrum of activity of three β-lactamase inhibitors such as amoxicillin/ clavulanic acid, ticarcillin/ clavulanic acid and piperacillin/ tazobactam in comparison to cephalosporins against gram negative bacilli.
Methods : Gram-negative bacilli isolated from the clinical specimens received in the laboratory were included in the study. Using the API system (bioMérieux) during a one-year period, a total of 1,252
Enterobacteriaceae and 385 non-fermenters were evaluated.
Results : The percentage resistance of the
Enterobacteriaceae isolates was 82.92% to amoxicillin/ clavulanic acid, 58.22% to ticarcillin/clavulanic acid and 22.44% to piperacillin/tazobactam respectively.
Pseudomonas aeruginosa
showed resistance of 96% to ticarcillin/ clavulanic acid and 61% to piperacillin/ tazobactam and
Acinetobacter baumannii
showed 49% resistance to ticarcillin/ clavulanic acid and 77% resistance to piperacillin/ tazobactam respectively. The isolates exhibited high resistance to all the generations of cephalosporins and the other groups of antibiotics except carbapenems.
Conclusions : Piperacillin/tazobactam was found to be the most active combination of the three against
Enterobacteriaceae and
Pseudomonas spp. and ticarcillin/clavulanic acid against
Acinetobacter spp. and
Stenotrophomonas maltophilia
.
