Bacteria are prokaryotic, single-celled microorganisms, among the first life forms to appear on Earth, and are present in most existing habitats. Escherichia coli is a Gram-negative, short bacillus that does not form spores; it is mobile, usually with peritric flagella, forming individual colonies or pairs. The genus Escherichia is part of the large Enterobacteriaceae family, having as a habitat, largely, the intestines of humans and animals. Because some strains cause serious infections and are resistant to conventional treatments, herbal extracts are studied and used, at least as an adjuvant, in the treatment of these conditions in humans and domestic animals. Herbal essential oils are increasingly popular, being used both in perfumery, cosmetics, and natural medicine industries. Currently, there are numerous scientific studies that have experienced the properties of these oils. In this research, the inhibitory effect of 19 essential oils on Escherichia coli was studied. The method used was the Kirby-Bauer diffusion method, often used in microbiology laboratories to test the antibiotic sensitivity of various bacteria. The reading of the results was achieved by measuring the inhibition zone in mm using a ruler, including the disc diameter (6 mm). The essential oils used were purchased commercially and the bacteria tested was Escherichia coli, a resource obtained from the “Horia Cernescu” Research Laboratory Complex of the “King Michael I of Romania” Banat University of Agricultural Sciences and Veterinary Medicine in Timisoara, Romania. The results obtained show that Escherichia coli is highly sensitive to oregano (34 mm), wild thyme (32 mm), garden thyme (27 mm), rosemary (25mm), tea tree (22 mm), and clove (21 mm) oils. It is very sensitive when treated with cinnamon oil (17 mm), peppermint (15 mm), and basil (15 mm), and sensitive when treated with lavander (10 mm), fennel (9 mm), dill (9 mm), garden sage (9 mm), and cumin (9 mm) oils. It is non-sensitive when treated with patchouli (0 mm), grapefruit (8 mm), vervain (8 mm), black cumin (7 mm), and rose geranium (7 mm) oils. The main objective of this study is to test some commercially obtained essential oils on E. coli bacteria to verify the veracity of these products and their effect on in vitro bacterial cultures.

Escherichia coli, essential oils, disk diffusion method, inhibition zone

field crops and pastures

Presentation: poster