The Combinatory Effects of Essential Oil from Lippia macrophylla on Multidrug Resistant Acinetobacter baumannii Clinical Isolates

• Published in: Chemistry & biodiversity 2024-10, Vol.21 (10), p.e202400537-n/a
• Main Authors: Silva Cirino, Isis Caroline, Santana, Caroline Ferreira, Vasconcelos Rocha, Igor, Souza, Larissa Isabela Oliveira, Silva, Marcia Vanusa, Bressan Queiroz de Figueiredo, Regina Celia, Coutinho, Henrique D. M., Leal‐Balbino, Tereza Cristina
• Format: Article
• Language: English
• Subjects: Acinetobacter baumannii; Acinetobacter baumannii - drug effects; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - isolation & purification; Anti-Bacterial Agents - pharmacology; Antibacterial agents; Antibiotic resistance; Antibiotics; Antiinfectives and antibacterials; Ceftazidime; Clinical isolates; Combination therapy; Dose-Response Relationship, Drug; Drug Resistance, Multiple, Bacterial - drug effects; Effectiveness; Essential oils; Humans; Imipenem; Lippia; Lippia - chemistry; Membranes; Microbial Sensitivity Tests; Minimum inhibitory concentration; Multidrug resistance; Oils & fats; Oils, Volatile - chemistry; Oils, Volatile - isolation & purification; Oils, Volatile - pharmacology; Ultrastructure
• ISSN: 1612-1872; 1612-1880; 1612-1880
• DOI: 10.1002/cbdv.202400537

To assess the antibacterial effectiveness of Lippia macrophylla essential oil (LMEO) against multidrug‐resistant Acinetobacter baumannii isolates, both as a standalone treatment and in combination with conventional antibiotics. LMEO demonstrated a significant inhibitory effect on the growth of A. baumannii, with a minimum inhibitory concentration (MIC) below 500 μg/mL. Notably, LMEO was capable of reversing the antibiotic resistance of clinical isolates or reducing their MIC values when used in combination with antibiotics, showing synergistic (FICI≤0.5) or additive effects. The combination of LMEO and imipenem was particularly effective, displaying synergistic interactions for most isolates. Ultrastructural analyses supported these findings, revealing that the combination of LMEO+ceftazidime compromised the membrane integrity of the Acb35 isolate, leading to cytoplasmic leakage and increased formation of Outer Membrane Vesicles (OMVs). Taken together our results point for the use of LMEO alone or in combination as an antibacterial agent against A. baumannii. These findings offer promising avenues for utilizing LMEO as a novel antibacterial strategy against drug‐resistant infections in healthcare settings, underscoring the potential of essential oils in enhancing antibiotic efficacy.