Evaluation of Meropenem and Gentamicin Synergy on Klebsiella pneumonaie

Abstract

Objective: Antimicrobial resistance is a severe global problem, causing both medical and economic results. Klebsiella pneumoniae (K. pneumoniae) is a gram-negative bacterium that plays a major role in these burdens due to its widespread resistance mechanisms. This study searchs for the synergy and antagonism between meropenem and gentamicin using the disk diffusion method and compares these findings with results from the checkerboard method. If the results are consistent, validating the reliability of the disk diffusion method, it could be a cost-effective alternative to other testing methods. Methods: The checkerboard method is used to assess the interaction of two antimicrobial agents (synergistic, indifferent, or antagonistic) by preparing a grid of wells containing varying concentrations of the agents. The fractional inhibitory concentration index (FICI) is calculated to evaluate the combination's efficacy. In the disc diffusion method, the antimicrobial activity of an agent is determined by placing discs soaked in the agent on an agar plate inoculated with bacteria. After incubation, the diameter of the inhibition zone is measured to assess susceptibility. Results: No synergy or antagonism was detected in any of the 30 Klebsiella pneumaniae isolates by either method. Conclusion: The disc diffusion method is a cost-effective and reliable alternative to other in vitro synergy tests, especially when facilities are limited.