Bactericidal activity of ethanolic extracts of propolis against Staphylococcus aureus isolated from mastitic cows
- 558 Downloads
Staphylococcus aureus is an important pathogen for both humans and animals, and it has been an ubiquitous etiological agent of bovine mastitis in dairy farms worldwide. Elimination of S. aureus with classic antibiotics is difficult, and the current study aimed to evaluate the efficacy of ethanolic extracts of propolis (EEP) against S. aureus cultivated in complex media or milk. EEP (0–0.5 mg ml−1) decreased growth of S. aureus in BHI media and 1 mg ml−1 was bactericidal against washed cell suspensions (107 CFU ml−1). Propolis extracts also killed S. aureus cells resuspended in milk, but the bactericidal dose was at least 20-fold greater. Cultures that were transferred for at least 60 generations with sub-lethal doses of propolis did not change much their sensibility to EEP. Atomic force microscopy images revealed changes in morphology and cell size of S. aureus cells exposed to EEP (0.5 mg ml−1). Our results indicate that propolis extracts might be effective against mastitis-causing S. aureus strains in vivo, but milk constituents affect the inhibitory activity of propolis. Considering that propolis-resistance appears to be a phenotype not easily selected, the use of EEP combined or not with other antimicrobial agents might be useful for mastitis control in vivo.
KeywordsBaccharis dracunculifolia Mastitis Udder infection AFM Dairy
The authors thank the Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG), Belo Horizonte, Brazil (Grant No. CBB-1318/06) for providing financial support for this research. HFS and AATC received fellowships from the Conselho de Desenvolvimento Científico e Tecnológico (CNPq). We thank Dr. Maximiliano Luis Munford, from the Physics Department at the Universidade Federal de Viçosa for technical assistance with the AFM analyses.
- Brito MAVP, Brito JRF (1999) Diagnóstico microbiológico da mastite. Circular Técnica 55, Embrapa Gado de Leite, Juiz de ForaGoogle Scholar
- Fischer G, Paulino N, Marcucci M, Siedler B, Munhoz L, Finger P, Vargas G, Hübner S, Vidor T, Roehe P (2010) Green propolis phenolic compounds act as vaccine adjuvants, improving humoral and cellular responses in mice inoculated with inactivated vaccines. Mem Inst Oswaldo Cruz 105:908–913CrossRefGoogle Scholar
- National Committee for Clinical Laboratory Standards (2003) Methods for dilution antimicrobial susceptibility test for bacteria that grow aerobically. Approved standard-sixth edition. Technical report M07-A6, Wayne, PAGoogle Scholar
- Pinto MS (2008) Atividade de própolis verde e bovicina HC5 sobre bactérias isoladas de mastite bovina. Thesis, Universidade Federal de ViçosaGoogle Scholar
- Raghukumar R, Vali L, Watson D, Fearnley J, Seidel V (2010) Antimethicillin resistant Staphylococcus aureus (MRSA) activity of ‘pacific propolis’ and isolated prenylflavanones. Phytother Res 24:1181–1187Google Scholar
- Varella Coelho M, Santos Nascimento J, Fagundes P, Madureira D, Oliveira S, Vasconcelos de Paiva Brito M, Freire Bastos M (2007) Activity of staphylococcal bacteriocins against Staphylococcus aureus and Streptococcus agalactiae involved in bovine mastitis. Res Microbiol 158:625–630CrossRefGoogle Scholar