Antibakterielle In-vitro-Wirksamkeit ätherischer Öle gegen veterinärmedizinisch relevante Keime klinischer Isolate von Hunden, Katzen und Pferden

Abstract

In vitro Antibacterial Activity of Essential Oils against Bacteria of Veterinary Relevance from Clinical Isolates of Dogs, Cats, and Horses Introduction: Essential oils are the basis for aromatherapy. They are supposed to have an antibacterial activity. The aim of this study was to determine the in vitro antibacterial activity of essential oils against a broad range of clinical isolates of bacteria which are relevant for veterinary medicine. Methods: The antibacterial activity of 16 essential oils was detected using the agar diffusion test. Gram-positive and gram-negative bacteria of clinical isolates of dogs, cats, and horses from veterinary routine diagnostic were used. Classification of antibacterial activity in not, lowly, moderately, and highly effective resulted from the size of the zone of inhibition of bacterial growth. Results: Overall, gram-positive and gram-negative bacteria were susceptible against essential oils. They showed an in vitro antibacterial activity against staphylococci including methicillin-resistant strains. Pasteurella multocida was rather sensitive, in great contrast to the totally resistant Pseudomonas aeruginosa. Tea tree, oregano, and winter savory oil seemed to be the most potent oils. In addition, lemongrass oil and thyme oil showed a good activity against gram-positive and gram-negative bacteria, respectively. Conclusion: Essential oils have an in vitro antibacterial activity against clinical isolates of dogs, cats, and horses. This study conducts basic information for the use of essential oils in veterinary medicine. Clearly, tendencies in the spectrum of efficacy of essential oils can be found, but no generalizing assertion about their activity against specific pathogenic bacteria in an individual patient should be made. Thus, before the beginning of a therapy with essential oils, their respective individual activity should be tested by an aromatogram.