Sensitivity pattern of gram negative bacilli to three beta-lactam/beta-lactamase inhibitor combinations using the automated API system.
OBJECTIVE
To evaluate the spectrum of activity of three beta-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 (bioMiotarieux) 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.
Anuradha
K
K
Department of Microbiology, Nizam's Institute of Medical Sciences, Hyderabad - 500 082, Andhra Pradesh, India.
Sailaja
V V
VV
Umabala
P
P
Satheesh
T
T
Lakshmi
V
V
D000150:Acinetobacter / Q000187:drug effects / Q000254:growth & development; D000658:Amoxicillin / Q000494:pharmacology; D019818:Clavulanic Acid / Q000494:pharmacology; D004755:Enterobacteriaceae / Q000187:drug effects / Q000254:growth & development; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000254:growth & development; D008826:Microbial Sensitivity Tests / Q000379:methods; D010397:Penicillanic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D010878:Piperacillin / Q000494:pharmacology; D011549:Pseudomonas / Q000187:drug effects / Q000254:growth & development; D020588:Stenotrophomonas / Q000187:drug effects / Q000254:growth & development; D000078142:Tazobactam; D013982:Ticarcillin / Q000494:pharmacology; D018440:beta-Lactam Resistance; D065093:beta-Lactamase Inhibitors; D047090:beta-Lactams / Q000494:pharmacology*
D004791:Enzyme Inhibitors; D065093:beta-Lactamase Inhibitors; D047090:beta-Lactams; D019818:Clavulanic Acid; D000658:Amoxicillin; D010397:Penicillanic Acid; D013982:Ticarcillin; D000078142:Tazobactam; D010878:Piperacillin