Atividade Antibacteriana de Extratos e Óleo Essencial de Anethum graveolens Frente a Isolados Clínicos de Origem Veterinária

Abstract

Traumatic wounds are veterinary medical conditions that compromise the therapeutic efficacy when contaminated. This therapeutic failure together with the indiscriminate use of antibiotics provides the development of bacterial resistance in both animals and humans are becoming a public health problem responsible for the deaths of thousands of people each year. The development of new drugs is compromised due to the slow progress of research in the pharmaceutical industry. As an alternative, medicinal plants are significant sources of biologically active molecules, an example of Anethum graveolens, (Dill) responsible for antioxidant, antifungal and antibacterial activity. However, literature is scarce due to its activity against resistant veterinary clinical isolates. Thus, the aim of this study was to evaluate the susceptibility profile of the bacteria isolated from traumatic wounds of patients treated at the Veterinary Hospital of the Federal University of Pelotas and the antibacterial activity of aqueous and ethanolic extracts and essential oil of Anethum graveolens against the clinical isolates. The essential oil extraction took place by hydrodistillation technique, unlike the aqueous and ethanolic extracts that were obtained by conventional techniques of maceration, in this way,the major compounds extracted from the essential oil were analyzed by gas chromatography coupled to mass spectrometry. The bacteria were collected with a sterile swab and identificated by Gram staining techniques; biochemical tests and also by the VITEK system, and your susceptibility profile by the disk diffusion technique, using the antibiotics ampicillin, amoxicillin, cephalexin, ceftriaxone, enrofloxacin, neomycin, oxacillin and penicillin G as standards. The minimum inhibitory concentration of the product in the microorganisms was determined by broth microdilution technique with concentrations ranging from 200 - 0.39 µg/mL and toxicity of the oil measured by the neutral red dye test. Fifty-eight bacteria were identicated, where Gram- bacteria showed a wide resistance profile, of up to 100% against penicillin G, amoxicillin and oxacillin. In general, the antibiotics neomycin, ceftriaxone and enrofloxacin were the most active. Pseudomonas spp. and Escherichia coli stood out among the Gran- bacteria, while Staphylococcus spp. was the genus isolated in the highest proportion among the Gram+. In this study, it can be seen that the essential oil was more active against the Gram-positive bacteria,where limonene (18.46%), dihydrocarvone (21.86%), carvone (33.73%) and apiol (14.56%) were identified while the aqueous and ethanolic extracts were more active against the Gram negative bacteria. The bactericidal activity was not observed since the results were not significant by F test. In summary, the dill proved to be a promising source of biomolecules with antibacterial potential, with activity against Gram+ and Gram resistant isolates. This showed that to minimize the effects of antimicrobial resistance, efforts should be cooperative between professionals of human and animal health, along with the identification of the microorganism associated with the infection as well as its susceptibility profile. These are imperative in choosing the appropriate antibiotic for therapy, thus avoiding the indiscriminate use that contributes to the spread of resistance.