Evaluation of the effect of Carvacrol and Linalool on the growth of Staphylococcus aureus and E. coli enterotoxin and production of ent A and ent B toxins in Staphylococcus aureus and ST1 and ST2 toxins in E. coli enterotoxins

Abstract

Diseases caused by the consumption of food contaminated with pathogenic bacteria are of a major threat to general health. Using natural substances as antimicrobial compounds seem effective for controlling the presence of pathogenic bacteria and increasing the shelf-life of processed foods. Among these compounds, extracts obtained from medicinal plants have antimicrobial properties and act as a source of antimicrobial substances against pathogens. Given their antimicrobial effects, herbal essences are usable as a substitute for antimicrobial chemicals in food industries. So the aim of this study was the evaluation of the effect of Carvacrol and Linalool on the growth of Staphylococcus aureus and E. coli enterotoxin and production of ent A and ent B toxins in Staphylococcus aureus and ST1 and ST2 toxins in E. coli enterotoxins. Carvacrol and linalool were prepared in dilutions of (1,500, 1/1000, 1/1500, 1/2000, 1/2500, 1/3000 ml / μg) and (1/100, 1/200, 1/400, 1/600, 1/800, 1/1000 ml/μg), respectively. The minimum inhibitory concentration was determined by the use of sterile 24 well plates and broth dilution. The minimum bactericidal concentration was obtained in a turbidity-absent culture, separately on the blood lipid agar medium in the case of Staphylococcus aureus, and Mckanaki agar in the case of Escherichia coli. Ent A and ent B toxins in Staphylococcus aureus were produced by high-performance liquid chromatography (HPLC) and STX 1 and STX 2 toxins in Escherichia coli were generated by Elisa method. The minimum inhibitory concentration of carvacrol was obtained at 1/1000 dilution on Escherichia coli, and 1/1500 dilution on Staphylococcus aureus, The minimum inhibitory concentration of linalool was obtained at 1/400 dilution on Escherichia coli and Staphylococcus aureus, the minimum bactericidal concentration of carvacrol was obtained at 1/1000 dilution on Escherichia coli and 1/2500 dilution on Staphylococcus aureus and the minimum bactericidal concentration of linalool was obtained at 1/400 dilution on Escherichia coli and Staphylococcus aureus. The effects of carvacrol and linalool on Ent A and Ent B toxins of Staphylococcus aureus and STX1 and STX2 toxins of E. coli showed the decreasing trend of toxin production at nanogram level. The results of this study showed that carvacrol and linalool had an inhibitory effect on the growth of both 2 bacteria and reduced the production of Ent A and Ent B toxins in Staphylococcus aureus and ST1 and ST2 toxins in Escherichia coli enterotoxigenic.