Abstract
Salmonella enterica is a ubiquitous and multi-host pathogen that causes significant morbidity and mortality worldwide. Outbreaks of foodborne salmonellosis continue to occur, highlighting the need for additional interventions. The present study investigated the potential for the commercial protective culture Hafnia alvei B16 to provide enhanced protection against multi-drug resistant strains of S. enterica serovars Typhimurium and Newport by attenuating their virulence when cocultured in milk (as a model food) and broth, and by protecting intestinal epithelial cells from pathogen infection in vitro. Exposure to HA in milk inhibited the subsequent adhesion of S. Typhimurium by 95.23%, whereas the invasion capacity of both serovars was reduced when cocultured with HA in broth and milk. The inhibition of invasion by S. Typhimurium and S. Newport was greater when cocultured in milk (86.95% and 86.58%, respectively) compared to broth (51.64% and 79.88%, respectively). Exposure to HA in both media decreased the expression of virulence genes in S. Typhimurium and S. Newport. Pre-treatment of Caco-2 cells with HA reduced invasion of S. Newport by 89.68% compared to control. These data demonstrate the potential for HA to enhance food safety by attenuating Salmonella virulence and protecting against pathogen invasion of intestinal epithelial cells.
•Coculture with B16 in milk reduced S. Typhimurium adhesion to human Caco-2 cells.•Coculture with B16 reduced subsequent Salmonella invasion of human Caco-2 cells.•Pre-treatment of Caco-2 cells with B16 reduced invasion of S. Newport.•Coculture with B16 decreased the expression of virulence genes in Salmonella.