Atividade antimicrobiana de Lippia origanoides Kunth (Verbenaceae) contra Staphylococcus spp. causadores de mastite bovina

Abstract

Mastitis is the disease that causes the greatest damage in dairy herds, as it causes a decrease in milk production, animal disposal and milk infected or contaminated with residues. To control this infection, antibiotic-based treatments are performed without medical advice and this is favoring the selection of resistant microorganisms. The use of plant extracts to fight infections of the mammary glands is already studied in order to reduce the indiscriminate use of antimicrobials. Lippia origanoides is a plant rich in essential oils and other bioactive substances that have strong antimicrobial potential, showing inhibition of bacteria of the genus Staphylococcus spp., considered important causes of infections in humans and animals. Thus, the objective of this work was to evaluate the phytochemical composition and antimicrobial activity of Lippia origanoides extract against bacteria isolated from cases of mastitis in cattle. After obtaining the hydroalcoholic extract, a high performance liquid chromatography (HPLC) analysis was performed to identify the major compounds. The antimicrobial activity of the extract was evaluated by the broth microdilution technique, and for conventional antibiotics, by the disk-diffusion test, against bacteria of the genus Staphylococcus spp. isolated from cases of mastitis in cattle. HPLC analysis revealed three major compounds that belong to the flavonoid group. The extract showed antibacterial activity against all samples tested, with minimum inhibitory concentration and minimum bactericidal concentration ranging from 187,5 to 1.500 μg/mL. In the disk diffusion test, a resistance profile to the antibiotics penicillin, tetracycline, erythromycin, clindamycin and cefoxitin was observed, with emphasis on the β-lactam penicillin, which was the antibiotic with the highest resistance rate. The extract of L. origanoides has a high content of flavonoids and has shown promising results as an antibacterial compound, and may be a low-cost alternative for the treatment of mastitis in cattle.