Comparative Evaluation of the in Vitro Activity of Three Combinations of Beta-Lactams with Beta-Lactamase Inhibitors: Amoxicillin/Clavulanic Acid, Piperacillin/Tazobactam and Ticarcillin/ Clavulanic Acid.

Background: In the modern era of increased use of β-lactam antibiotics, resistances to bacteria become a major problem. To overcome this specific resistance mechanism, β-lactam antibiotics are often given with β-lactamase inhibitors like clavulanicacid, salbactam or tazobactam. Aims and Objectives: To comparein vitro activity of betalactam/beta-lactamase inhibitor combinations (Amoxycillin / Clavulanic acid, Ticarcillin / Clavulanic acid and piperacillin/Tazobactam) among gram negative isolates. Material and method: Gram negative bacilli found resistant to penicillin drugs or one or more cephalosporin drugs, were tested for three β-lactam / β-lactamase inhibitor combinations. Antibiotic susceptibility testing was carried out by disc diffusion method as per CLSI guidelines. Result: Total 7800 samples were received, from these 3816 were positive and 3984 were negative for isolates. From positive culture, 1000 were GPC and 2819 were GNB. Susceptibility of the enterobacteriaceae to Augmentin, Piperacillin-Tazobactam and Ticarcillin-Clavulanicacid were 34.82%, 71.64% & 39.8%. Conclusion: Overall piperacillin/ tazobactam was observed to be the best combination agent. Comparative Evaluation of the in Vitro Activity of Three Combinations of Beta-Lactams with BetaLactamase Inhibitors: Amoxicillin/Clavulanic Acid, Piperacillin/Tazobactam and Ticarcillin/ Clavulanic Acid.