In vitro inhibition of growth of Erwinia amyloyora by plant oils

摘要

Previous studies have demonstrated the antimicrobial properties of essential oils and their constituentsfrom a wide variety of plants being effective against different microorganisms. The aim of the thisinvestigation was to assess the antibacterial activities of test oils against E. amylovora. Thirty fouressential oils from medicinal plants grown in Hungary were investigated using the agar diffusion method.Experiments were carried out in vitro to determine the magnitude of antibacterial activity of essential oils(Aromax Rt, Budapest) towards different antibiotic sensitive and resistant strains of E. amylovora: Eal[Strep~s Hungary (H), apple] , Ea 110 (Rif~RUSA, apple), Ea 88 (Strept~R USA, pear) and Ca 11 (Strept~RUSA, apple). Other species such as Pseudomonas syringae pv. syringae P53 (H, pepper), P. savastanoipv. phaseolicola El356 (H, bean), Xanthomonas vesicatoria XV73 (H, pepper), XVS03 (H, tomato)served as test bacteria. In the first selection ten different oils displayed a very effective inhibition of bacteria. From this groupthree oils of Mentha, Thymus, and Tagetes spp. displayed the most comprehensive inhibitory propertieseven in a dilution of 1:4. Gas chromatography analysis showed that the most effective components arecarvone, dihydrocarvone, thymol, and carvacrol. There was no difference between the antibiotic sensitive(Hungarian) and resistant (USA) E. amylovora strains in their reaction to essential oils.