Comparative Assessment of the Antibacterial Efficacy of Zingiber officinale Extracts Against Multidrug Resistant Gram Negative Bacteria

Abstract

: Multidrug-resistant Gram-negative bacteria (MRSAs) pose a serious global health challenge, prompting this study to evaluate the antibacterial activity of aqueous, ethanolic, and methanolic extracts of ginger (Zingiber officinale) against clinically resistant isolates: Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa .Phytochemical screening was performed to identify active compounds, and antimicrobial activity was assessed using the disk diffusion assay and the broth microdilution method to determine the minimum inhibitory concentration (MIC) and lethal concentration (MBC) across six independent biological replicates. The results showed that the ethanolic extract was superior, containing the highest percentage of active compounds and achieving the largest inhibition zones, reaching 18 mm against A. baumannii, 15 mm against E. coli, 14 mm against K. pneumoniae, and 12 mm against P . aeruginosa , followed by the methanolic extract, while the aqueous extract was the least effective. The ethanolic extract recorded the lowest MIC values (6–10 mg/ml) and MBC values (10–14 mg/ml). A. baumannii was found to be the most susceptible, while P. aeruginosa exhibited the highest resistance. The MBC/MIC ratio (1.4–1.67) indicated that the organic extracts possess bactericidal activity. These results confirm that organic ginger extracts exhibit in vitro bactericidal activity against Gram-negative strains and highlight the crucial role of the solvent in extraction efficiency. Ginger holds promising potential as a natural antimicrobial source, paving the way for further studies to isolate its active components and evaluate their therapeutic potential.