Gomes, FernandaRodrigues, Maria ElisaMartins, NatáliaFerreira, Isabel C.F.R.Henriques, Mariana2018-02-192020-01-062018-01-192020-01-062019Gomes, Fernanda; Rodrigues, Maria Elisa; Martins, Natália; Ferreira, Isabel C.F.R.; Henriques, Mariana (2019). Phenolic plant extracts versus penicillin G: In vitro susceptibility of Staphylococcus aureus isolated from bovine mastitis. Pharmaceuticals. ISSN 1424-8247. 12, p. 1-8http://hdl.handle.net/10198/20261Antibiotics are the elective drugs in bovine mastitis (BM) treatment, despite their low rates of e ciency and e ectiveness and increasing risk of pathogen resistance. In this sense, it is urgent to discover new and e ective antimicrobial agents to apply in BM control and even treatment. Plant extracts have been widely recognized as a rich source of phytochemicals with antimicrobial potential. Thus, the present work aims to compare the bioactivity of Eucalyptus globulus and Juglans regia extracts against Staphylococcus aureus bovine mastitis strains with penicillin G. At non-toxic concentrations, E. globulus exerted a bacteriostatic e ect in planktonic cells and J. regia had no antimicrobial activity. Penicillin G, at minimum inhibitory concentration (MIC), demonstrated bactericidal activity, but just for S. aureus 3, 5, 6 and ATCC 25923, while the other strains seem to have acquired resistance. On the other hand, E. globulus and penicillin G in combination demonstrated synergy, being the most e ective approach against S. aureus 1, 2 and 4. Thus, penicillin alone and in combination with E. globulus or J. regia seems to be promissory strategies to control bovine mastitis infections.engBovine mastitisEucalyptus globulus LabillJuglans regia L.Penicillin GStaphylococcus aureusjournal article10.3390/ph12030128