Antibiotics - Mentha piperita essential oil synergism inhinibts mature bacterial biofilm

Essential oils (EOs) are known for their antimicrobial and antiinflammatory properties and they could be used for treatment of several microbial infections in synergy with commercially available antibiotics. The synergistic effects between EOs and drugs would aim to reduce the side effects of antibiotic therapies, so,the goal of our research has been to highlight the potential synergistic effect between Mentha x piperita L. EO and three widely used antibiotics (Gentamicin, Oxacillin, Norfloxacin) on biofilm formation and growth. Gas chromatography hyphenated with mass spectrometry technique was employed to assess the EO chemical profile. The in vitro efficacy of the EO-Drug associations was evaluated against four different strains of Gram-positive bacteria, forming biofilms. Synergistic effects were tested using the chequerboard microdilution method and FIC index., All the combination of EO with antibiotics are able to produce a substantial inhibition of bacterial biofilms growth.