Antibacterial Potential of Chitosan Scaffolds Incorporated with Oregano and Thyme Essential Oils against Escherichia coli

Abstract

The aim of this study was to evaluate the antibacterial potential of chitosan-based scaffolds associated with the essential oils of Origanum vulgare L. and Thymus vulgaris L. against a strain of Escherichia coli. The antibacterial potential was assessed by reading the inhibition halos formed around the chitosan-based scaffolds incorporated with thyme EO, oregano EO and thyme and oregano EO against the Escherichia coli strain, using the Mueller Hinton agar diffusion methodology per well. To do this, Mueller Hinton Agar was used as the culture medium in Petri dishes, and holes 6 mm in diameter were formed using a mold to create the wells. The plates were inoculated with the microorganism using a swab, then incubated in a bacteriological oven at 37 °C for 24 hours. Scaffolds, in the form of disks, were aseptically deposited in the wells of the inoculated media, which were incubated at 37 °C for 24 hours. After incubation, the plates were observed for homogeneity of bacterial growth and the diameter of the inhibitory halo was measured using a millimeter ruler in cases where inhibition of bacterial growth was verified. The tests were carried out in duplicate and the results correspond to the average values. The association of chitosan with Origanum vulgare L. and Thymus vulgaris L. EOs was found to have antibacterial activity against the Escherichia coli strain. For the scaffolds incorporated with Origanum vulgare L. EO, Thymus vulgaris L. EO and associated Origanum vulgare L. and Thymus vulgaris L. EOs, 16 mm inhibition halos were formed against the Escherichia coli strain. The association of chitosan with the EOs of Origanum vulgare L. and Thymus vulgaris L. has antibacterial activity, acting as a bactericide against the Escherichia coli strain tested.