Antibacterial, antibiofilm, and pharmacokinetic properties of some Lamiaceae essential oils against methicillin- and vancomycin-resistant staphylococcus aureus

The presence of methicillin-resistant (MRSA) and vancomycin-resistant (VRSA) Staphylococcus aureus in food raises a public health concern. This study aimed to investigate the antibacterial and anti-biofilm activity of some Lamiaceae essential oils including Melissa Officinalis, Salvia officinalis, and Mentha piperita against MRSA and for the first time on VRSA strains. For this purpose, the disk diffusion test, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), minimum biofilm inhibitory concentration (MBIC), and minimum biofilm eradication concentration (MBEC) were determined. Then, M. Officinalis essential oil compounds were investigated against PBP2a, agrA, and Bap proteins using AutoDocK Vina. Finally, pharmacokinetic properties were investigated using ADMETsar and SwissADME servers. Based on the obtained results, the MIC and MBC values of M. Officinalis essential oil against MRSA strain were equal to 0.05 and 0.112 mg/ml, and against VRSA strain were equal to 1.8 and 2.5 mg/ml, respectively. The MBIC and MBEC of M. Officinalis essential oil against MRSA strain were equal to 0.03 mg/ml and 0.112 mg/ml, and against VRSA strain were equal to 0.9 mg/ml and 3.2 mg/ml, respectively. The results of molecular docking showed that β-Caryophyllene had a greater binding affinity to PBP2a protein either in the active site or in the allosteric site (-6.6kcal/mol). On the other hand, the effective compounds of this essential oil, especially citronellol, thymol, and citral, were acceptable in terms of pharmacokinetic properties. Since natural antibiotics can be an alternative to conventional antibiotics in the treatment of Staphylococcus aureus food-borne diseases, the results of this study showed that Melissa Officinalis essential oil is effective on the growth and biofilm of MRSA and VRSA strains, and it can be used as a drug candidate in the prevention and treatment of infections caused by antibiotic-resistant strains of this bacterium.