Evaluation of Synergistic Effect of Cefuroxime and Clavulanic Acid against Escherichia Coli

Background: β-lactamase mediated resistance is the most common mechanism which renders the β-lactam antibiotics ineffective against bacteria including Escherichia coli. The development of resistance has led to the widespread empirical use of higher generation cephalosporins and it is likely that the third generation cephalosporins are also losing their efficacy by the same mechanism. The present study was conducted to evaluate the and microbial effect of cefuroxime with and without a β-lactamase inhibitor named clavulanic acid, against Escherichia coli. Research Methodology: An institution based analytic observational study was carried out at Department of Microbiology, Khyber Medical College, Peshawar. β-lactamase producing Escherichia. coli were identified and cultured in Mueller Hinton medium in petridishes. The antibiotic disks containing cefuroxime alone and in combination with clavulanic acid were placed in the same petridishes about 24-30 mm apart. The zones of inhibition were measured according to NCCLs zone diameter criteria using disk diffusion method. Results: A total of 40 β-lactamase producing bacteria were isolated. The zones of inhibition surrounding the disks containing both cefuroxime and clavulanic acid were larger than those containing cefuroxime alone. Conclusion: In this study it was found that the synergistic antibacterial effect of the combination of cefuroxime and clavulanic acid was far more than the cefuroxime alone against Escherichia coli.