Short chain fatty acids alter HEp-2 cell association and invasion by stationary growth phase salmonella typhimurium

We examined the ability of stationary phase Salmonella typhimurium to adher e and invade cultured HEp-2 cells after growth in broth supplemented with a cetate, propionate, butyrate, or a mixture of the three short chain fatty a cids (SCFA). At pH 6, all concentrations, except 25 and 50 mM butyrate, red uced cell-association of S. typhimurium when compared to controls, while at pH 7 only 100 mM concentrations of acetate and butyrate reduced cell-assoc iation significantly. Invasion percentages were greater for S. typhimurium grown at an initial pH of 6 with 25 mM acetate when compared to controls, S CFA mixture, and all other single SCFA concentration combinations. At pH 7, invasion was greater with either the SCFA mixture or 25 or 50 mM acetate t han with control and all other single SCFA concentration combinations.