Pathogenic potential and clonal profile of Staphylococcus spp. in milk of cows with unconventional treatment of mastitis

• Grant number: 17/08979-7
• Support Opportunities: Regular Research Grants
• Start date: August 01, 2017
• End date: January 31, 2020
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Preventive Veterinary Medicine
• Principal Investigator: Luiz Francisco Zafalon
• Grantee: Luiz Francisco Zafalon
• Host Institution: Embrapa Pecuária Sudeste. Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA). Ministério da Agricultura, Pecuária e Abastecimento (Brasil). São Carlos , SP, Brazil

Abstract

Mastitis is one of the major diseases in dairy cattle, as it causes great economic losses to producers due to the reduction of milk production and changes in the quality of the product. The disease is mainly caused by bacteria of the genus Staphylococcus spp. These microorganisms have the ability to express various virulence factors and mechanisms of resistance to antimicrobial agents. In herds with organic management, producers and technicians use unconventional ways to treat and control the disease, such as homeopathy. However, it is not known if this type of treatment is able to control pathogenic bacteria such as those of the genus Staphylococcus, of relevance to animal and human health. Thus, this study aims to characterize the virulence factors and the clonal profile of Staphylococcus spp. isolated from milk samples from cows with subclinical mastitis submitted to homeopathic formulation for one year. The milk samples were collected between October of 2015 and September of 2016, in a herd formed by Holstein and Jersolandas cows. The etiology of the disease was preliminarily identified through colony growth characteristics and biochemical tests. Bacteria identified as belonging to the genus Staphylococcus will undergo confirmatory tests for species identification, investigation of enterotoxin-encoding genes, toxic shock syndrome toxin (TSST-1), Panton Valentine's leukocidin (PVL), as well as genes related to the formation of biofilms, in addition to gene research related to oxacillin resistance (mecA). The clonal profile of Staphylococcus will be studied to evaluate the dissemination of microorganisms in animals with and without mastitis treatment. From the results obtained, it is expected a more extensive understanding about the behavior of these bacteria in a herd submitted to this type of treatment and the consequences for the health of the mammary gland, which will generate subsidies to producers and technicians on choices to control the disease. (AU)