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Therapeutic alternatives against Staphylococcus spp. multiresistant isolated from Bovine Mastitis

Grant number: 20/09249-5
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): September 01, 2020
Effective date (End): March 31, 2021
Field of knowledge:Agronomical Sciences - Animal Husbandry - Animal Production
Principal Investigator:Lenira El Faro Zadra
Grantee:Lívia Castelani
Home Institution: Instituto de Zootecnia. Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Nova Odessa , SP, Brazil
Associated research grant:17/50339-5 - Institutional research development plan of the Animal Science Institute , AP.PDIP

Abstract

Staphylococcus spp. are microorganisms of great significance for dairy cattle worldwide. It is responsible for massive production losses and alterations in milk' centesimal composition. Besides, it is highly contagious pathogens, with low response to conventional treatments due to high levels of antimicrobial resistance and diversity of virulence factors. Therefore, it is necessary the search for new safer and effective antimicrobial molecules as alternatives. Bacteriocins, natural peptides synthesized and secreted by antimicrobial activity bacteria and plant origin compounds are promising sources to development of new therapeutic formulations. Thus, the aim of this research is to evaluate in vitro antimicrobial activity of bacteriocin nisin and different essential oils against resistant Staphylococcus spp. strains planktonic and in biofilms cells, obtained from bovine mastitis and strains ATCCs, as well as the potentially synergism between molecules, aiming the development of therapeutic alternative formulations. Bacterial resistance will be characterized through disk diffusion method and PCR. Biofilms production will be phenotypically and genotypically determined. In addition, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) will be determined for each compound and from the interaction between them against planktonic cells, biofilms and raw milk. In vitro activity from these compounds against bacterial strains will be evaluated according to interaction time using time-kill curves. The cytotoxic effect from molecules will be assessed in MAC-T mammary cells culture. Physicochemical interactions from molecules will be determined by size, polydispersity and surface charge. (AU)