Genetic diversity, cholesterol reduction, and presence of conserved bile salt hydrolase gene in probiotic strains from human milk.

Abstract

Probiotics are known to possess strain- and species-specific functional properties, of which hypocholesteremia is of major interest. Bile salt hydrolase (BSH) activity is one of the key mechanisms involved in the hypocholesterolemic effect. The study was designed to genetically characterize probiotics obtained from human milk on the basis of simple sequence repeat (SSR), isolate potent hypocholesterolemic strains, and detect BSH activity, deconjugation of bile salts, and bsh polymorphism. This study, for the first time, linked genetic diversity with cholesterol reduction potential and proved the presence of conserved bsh of Levilactobacillus brevis in genetically diverse species. The strains displayed 2.78%-42.23% cholesterol reduction, which was not influenced by prebiotics. In this study, data obtained from SSR markers indicated 93.3% diversity, and based on cluster analysis, they were distributed into XI clades; out of five potent cholesterol-reducing strains, three belonged to clade I. The strains could deconjugate both sodium glycocholate and sodium taurocholate, but we preferred using sodium glycocholate. The variation in cholesterol reduction potential and BSH activity pointed toward the presence of more than one bsh in the strains. Weissella confusa MW051433 displayed highest cholesterol reduction (42.23%) and specific BSH activity (2.64U ml -1). Search for other bsh and in vivo assessments of cholesterol reduction by W. confusa MW051433 have been proposed.