Chemical Composition and Antibacterial Activity of Citrus Peels Essential Oils Against Multidrug-Resistant Bacteria: A Comparative Study

Introduction: Multidrug-resistant bacteria pose major challenges for clinicians. Essential oils hold great promise for the development of new and effective anti-infective treatments. This study investigated the chemical composition and antibacterial activity of essential oils extracted from the barks of Citrus sinensis, Citrus limon, and Citrus aurantium. Methods: The essential oils from citrus peels were obtained by hydrodistillation using a Clevenger apparatus and analyzed by gas chromatography-mass spectrometry (GC-MS). Antibacterial activity was assessed by both agar diffusion and broth microdilution methods. We tested these essential oils against six bacterial strains, including four clinical multidrug-resistant bacteria: extended-spectrum j3-lactamase-producing Escherichia coli, carbapenem-resistant Acinetobacter baumannii, ceftazidime-resistant Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus, in addition to two reference bacterial strains, Escherichia coli (EC) ATCC 25922 and Staphylococcus aureus (SA) ATCC 29213. Results: The chemical analysis revealed the presence of 26 compounds, with D-Limonene being the dominant one. The essential oils demonstrated significant antibacterial properties against all examined bacterial strains. They exhibited low MICs, ranging from 110 mu g/mL to 140 mu g/mL, against EC ATCC 25922, carbapenem-resistant Acinetobacter baumannii, extended-spectrum j3-lactamase-producing Escherichia coli, and ceftazidime-resistant Pseudomonas aeruginosa. Moreover, they also effectively inhibited SA ATCC 29213 and methicillin-resistant Staphylococcus aureus at slightly higher MICs, ranging from 200 mu g/mL to 220 mu g/mL. Conclusions: In this report, we demonstrate the significant antibacterial activity of citrus peel essential oils against multidrug-resistant bacteria. This could be the result of synergistic interactions between the various natural chemical compounds, encouraging their use in the discovery of new antibacterial drugs.