Short Chain Fatty Acids Alter HEp‐2 Cell Association and Invasion by Stationary Growth Phase Salmonella Typhimurium

Abstract

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

Salmonella Pathogenicity and Host Adaptation in Chicken-Associated Serovars

“…There were also indications that these S. Typhimurium responses were growth dependent, particularly in the presence of propionate and butyrate at pH 6.0, which reduced the growth rate considerably (341). However, when late-logarithmic-phase (12 h) and stationary-phase (18 h) S. Typhimurium cells were compared (342,343), all SCFAs reduced cell attachment at pH 6.0 and 7.0 but only marginally influenced invasion for late-log-phase cultures of Salmonella. The stationary-phase Salmonella cells exhibited reduced attachment only in the presence of SCFA at pH 6.0, while actual increases in invasion occurred for lower concentrations of acetate (342,343).…”

“…However, when late-logarithmic-phase (12 h) and stationary-phase (18 h) S. Typhimurium cells were compared (342,343), all SCFAs reduced cell attachment at pH 6.0 and 7.0 but only marginally influenced invasion for late-log-phase cultures of Salmonella. The stationary-phase Salmonella cells exhibited reduced attachment only in the presence of SCFA at pH 6.0, while actual increases in invasion occurred for lower concentrations of acetate (342,343). Van Immerseel et al, using avian intestinal and cecal epithelial cell lines, also observed increases in invasion of S. Enteritidis exposed to acetate for 4 h and decreases with propionate and butyrate (265,344).…”

“…Durant et al conducted a series of tissue culture studies with an epidermal carcinoma cell line (HEp-2) to determine the influence of S. Typhimurium after growth in either a mixture or separate intestinal concentrations of SCFA (acetate, propionate, and butyrate at pH 6.0 or 7.0) on its subsequent ability to adhere to and invade tissue culture cells (341)(342)(343). For S. Typhimurium incubated for 4 h in the presence of SCFA, acetate at pH 6.0 and 7.0 did not alter attachment, and only slight increases in invasion occurred, while propionate and butyrate dramatically decreased attachment and invasion at pH 6.0 but not at pH 7.0.…”

Short Chain Fatty Acids Influence Virulence Properties ofSalmonella EntericaSerovar Typhimurium

“…can combat this stress by adaptation and acid tolerance response. [12,13,25] In the present study, the surface hydrophobicity of cells during logarithmic as well as stationary phase was evaluated by binding of congo red dye to bacterial cells. Mouse lethality determination revealed a 30-fold decrease in LD 50 of SCFA exposed cells (2.163 × 10 3 organisms/mouse) as compared to the normal cells (6.46 × 10 4 organisms/mouse).…”

“…[4] One of the potential stress conditions that can be encountered by the food-borne pathogens like Salmonella is their exposure to short chain fatty acids (SCFA), particularly acetate, propionate, and butyrate. [12,13] SCFA have also been observed to modulate the expression of Salmonella pathogenicity island invasion genes including hilA and invF. These acids can be found in concentrations as high as 190 mM in gastrointestinal ecosystems harboring extensive populations of fermentative anaerobic bacteria.…”