Algas e leveduras isoladas de mastite bovina: identificação e perfil de sensibilidade a antissépticos e antimicrobianos

Abstract

Bovine mastitis is one of the most prevalent and impacting diseases in dairy cattle. Different microorganisms are involved in their etiology, being classified as contagious, when adapted to the interior of the mammary gland, or environmental, normally present in the environment of animal husbandry. Among environmental agents, algae and yeasts are unusual agents, but considered emerging. In the present study, 149 yeast strains and 62 strains of algae isolated from cases of mastitis in bovine herds of São Paulo, Minas Gerais and Paraná were evaluated for the antimicrobial and antiseptic susceptibility profile, using the minimum inhibitory concentration. In addition, isolated yeasts were characterized by the MALDI-TOF technique. A minimum inhibitory concentration (MIC) test did not show growth of algae at the concentration of 4% gentamicin, 16% amikacin and 8% polymyxin B. Different rates of algae growth inhibition were observed for antiseptics: for triclosan 0.25%, quaternary ammonia <0.01%, hydrogen peroxide <0.002%, iodine 0.015, peracetic acid 0.25%, sodium hypochlorite 0.125% and chlorhexine <0.018%, there was growth of algae at the highest acid concentrations lactic acid and glutaraldehyde. The MIC results for yeast were: <0.0015% for triclosan, quaternary ammonia <0.02%, hydrogen peroxide <0.007%, iodine 0.125%, peracetic acid 0.125%, chlorhexidine <0.0018 and sodium hypochlorite in concentration of 0.125%. These results confirm the efficacy of these agents as an asepsis mechanism in dairy farms. There was growth of yeasts in the highest concentrations of lactic acid and glutaraldehyde. With the protein identification technique, the profile of the isolates was traced, identifying 6 yeast species with predominance of Issatchenkia orientalis, if in a herd there was identification of more than one isolate, but with a predominance of species. In vivo tests should be performed to confirm the sensitivity of the isolates to the antibiotics tested. According to this study, the results endorse the use of antiseptics for roof antisepsis (pre and post-immersion), aiming at the control and prevention of mastitis caused by these environmental agents of bovine mastitis. The yeast species identified in this study resemble species already identified in the literature.