Anti-Biofilm Inhibitory Synergistic Effects of Combinations of Essential Oils and Antibiotics

Abstract

In recent years, the increase of bacteria antibiotic- resistance has been a severe problem for public health. A useful solution could be to join some phytochemicals naturally present in essential oils (EOs) to the existing antibiotics, with the aim to increase their efficacy in therapies. According to in vitro studies, EOs and their components could show such effects. Among them, we studied the activity of Cinnammonum zeylanicum, Mentha piperita, Origanum vulgare, and Thymus vulgaris EOs on bacterial biofilm and their synergism when used in association with some common antibiotics such as norfloxacin, oxacillin, and gentamicin. The chemical composition of EOs was determined using gas chromatography (GC) coupled with mass spectrometry (MS) techniques. The EOs drug efficacy was evaluated on four different strains of Gram-positive bacteria forming biofilms. The synergistic effects were tested through the chequerboard microdilution method. The association EOs-antibiotics showed a strong destruction of the biofilm growth of the four bacterial species considered. The interaction of norfloxacin with EOs was the most effective in all the tested combinations against the strains object of this study. These preliminary results suggest the formulation of a new generation of antimicrobial agents based on a combination of antimicrobial compounds with different origin.

Synergistic Activity of New Diclofenac and Essential Oils Combinations against Different Candida spp.

“…Our previous studies on EOs showed their synergy with some commercially available antibiotics and demonstrated the effectiveness of these associations by proposing the possibility of a new therapeutic use [31][32][33][34][35].…”

Virucidal and antiviral effects of Thymus vulgaris essential oil on feline coronavirus

“…TEO (Specchiasol Bussolengo, Verona - Italy) composition was determined in three independent experiments using the gas chromatography hyphenated with mass spectrometry (GC-MS) technique, as recently reported ( Rosato et al, 2020 ). Details of sample preparation, instruments and GC-MS analysis methods have been previously reported ( Salvagno et al, 2020 ; Rosato et al, 2018 ).…”

Mechanistic Study of Synergistic Antimicrobial Effects between Poly (3-hydroxybutyrate) Oligomer and Polyethylene Glycol

“…The mixture of PHB powder and PEG after treatment under 150 °C possesses higher antibacterial reduction than each of the individual components. Some antimicrobial agents, such as reactive oxygen species [ 21 ], and radical [ 22 ] and new molecules [ 23 ], may be produced as a result of possible chemical reaction between the mixing components, leading to a better antimicrobial effect than each individual component. To see if this hypothesis was true or false, the mass spectrum (MS) was carried out for the solid and liquid part of mixture of PHB powder and PEG after heat treatment, as well as the individual PHB powder and PEG after heat treatment under 150 °C for 4 h. It can be seen from Figure 4 A that there is no difference between PHB powder and the solid part of mixture of PHB powder and PEG after heat treatment, which means that no new solid antimicrobial component is produced after the reaction of PHB powder and PEG under high temperature.…”