Staphylococcus spp. multidrug-resistant isolated from bovine mastitis: alternative treatments based on the use of bacteriocins and cationic lipid nano-fragments

Abstract

Staphylococcus spp. are reported as one of the main agents of bovine mastitis. These microorganisms present several virulence factors, such as toxin production and biofilm formation, which contribute to its pathogenicity and persistence in the mammary gland. Another relevant factor is the isolation of multidrug-resistant and which do not respond to conventional treatments. In addition, antimicrobial drugs used in the treatment of mastitis generate residuals that alter food quality and milk safety and its derivatives. In this scene, new treatment and control alternatives are indispensable. Bacteriocins and nanoparticles have emerged as promising alternatives for further development of antimicrobial agents. This project aims to in vitro evaluation of the antibacterial efficacy of bacteriocin Nisin and nanofragments of the cationic lipid dioctadecyldimethylammonium bromide (DDA) against resistant strains and/or virulent Staphylococcus spp. isolated from mastitis in heifers and primiparous cows in lactation, as well as to correlate the efficacy of treatment with the resistance and / or virulence. Strains of Staphylococcus spp. isolated from heifers and cows with mastitis collection belonging to the Milk Quality Laboratory of the Instituto de Zootecnia - CAPTA Bovinos de Leite - Nova Odessa - SP will be used. Screening of resistant strains will be determined by the disc diffusion method and MIC determination, virulence genes and resistance will be investigated by PCR and later confirmed by sequencing. The activity in vitro of Nisin and DDA against Staphylococcus spp. will be evaluated in function of interaction time using death curves (time-kill). (AU)