Probiotic potential and biofilm inhibitory activity of Lactobacillus casei group strains isolated from infant feces

Probiotic bacteria are receiving growing interest, particularly for the preparation of functional foods. In the present study, eight Lactobacillus strains, newly isolated from infant feces, were investigated for the presence of probiotic properties such as antimicrobial susceptibility, hemolytic activity, resistance to simulated gastro-intestinal conditions, bile salts hydrolytic activity, inhibitory ability against biofilm formation by other bacteria, attachment to HT-29 human cancer cells and anti-cancer activity. All the strains tested highlighted interesting properties, but L. paracasei DTA93 and L. paracasei DTA81 appeared of particular interest. Some properties of these two strains resulted similar, and in some cases superior, to the reference widespread probiotic commercial strain L. rhamnosus GG. Strain L. paracasei DTA81 possesses amazingly high adherence ability to HT-29 cells, about ten times higher than that of L. rhatnnosus GG. Moreover, L. paracasei DTA93 and L. paracasei DTA81 were able to effectively inhibit biofilm formation of Escherichia coli and Listeria innocua.