Staphylococcus aureus resistentes a meticilina e meropenem em leite de vacas com mastite subclínica

Abstract

Staphylococcus aureus is the most common pathogen in bovine mastitis. Resistance to methicillin is of concern in animal production and carbapenems are still poorly described in the literature in relation to this bacterium. The aim of this study wasto investigate the frequency of Staphylococcus aureusin subclinical bovine mastitis in farms in the north of Minas Gerais and to determine the sensitivity to beta-lactams. For this, the California Mastitis Test was performed and milk samples were collected from subclinical teats. It was performed sown on blood agar and the nmicrobial identification by MALDI-TOF. The susceptibility of Staphylococcus aureus to the antimicrobials amoxacillin, oxacillin, ampicillin / sulbactam, cefoxitin, imipenem and meropenem was tested by disk diffusion. As aresult,214 microorganisms were detected, with Staphylococcus being the most frequent genus (N = 146) and, of these, 79 were of the aureus species. Among Staphylococcus aureus, 30 (37.9%) isolates were resistant to cefoxitin and the rest (62.1%) sensitive to thedrug. In relation to oxacillin sensitivity test,29 (36.7%) were resistant. There were amoxicillinresistance in27isolates(34.2%)andmeropenemresistancein9 (11.4%). There was a significant association between resistance and farm of origin of the isolates.