Induction of Resistance of Salmonella typhimurium to Environmental Stresses by Exposure to Short‐Chain Fatty Acids

Abstract

Short-chain fatty acids (SCFA), which are widely used as food preservatives and are also present in the gastrointestinal (GI) tract of animals at high concentrations, may play a role in the persistence of Salmonella typhimurium in the environment. To test the hypothesis, S. typhimurium was adapted to SCFA for 1 h and the % survivors against various stress conditions was determined. For adaptation, the SCFA mixtures at the concentrations found in small (SI) and large intestine (LI) were used. The % survivors against extreme acid (pH 3.0), high osmolarity (2.5 M NaCl), and reactive oxygen (20 mM H 2 O 2 ) was greatly increased by exposure to SCFA LI, but to a much less extent by SCFA SI. The results suggest that encountering SCFA by S. typhimurium in the large intestine of the host food animal or food materials treated with them may increase the persistence of S. typhimurium in food animal preand postharvest production by enhancing overall stress resistance.

Salmonella Pathogenicity and Host Adaptation in Chicken-Associated Serovars

“…Responses were dependent on the type of acid used and were time dependent, with hilA being upregulated after a 2-h exposure to the respective acid (350). When Milillo et al compared S. Typhimurium transcriptome responses to sodium acetate and sodium propionate exposure after 1 min (55°C at pH 4.0), the respective gene expression patterns were similar, with no increases in expression levels of rpoS, phoPQ, or virulence factors despite their established roles in organic and inorganic acid stress (35,327,328,338). Conversely, genes related to attachment and/or motility functions were induced, which has been observed previously for S. Typhimurium attachment genes after exposure to 42°C (351).…”

“…The protection against organic acids did not occur if organic acids were used for the initial acid shock. When Kwon and Ricke exposed S. Typhimurium to SCFA at neutral pH for 1 h, they observed that acid tolerance was greater for cells exposed to acetate or propionate than for cells exposed to butyrate or valeric acid and was enhanced under anaerobic incubation conditions (328). Calhoun and Kwon observed substantial enhanced acid tolerance in S. Enteritidis when exposed to 100 mM propionate at neutral pH over a longer period of time (16 h) (329).…”

Effects of Dietary Saccharomyces cerevisiae and Butyric Acid Glycerides on Performance and Serum Lipid Level of Broiler Chickens

“…Also, butyric acid is known the main energy source for enterocytes. Kwon and Ricke [12] showed butyrate and valerate to have the greatest efficacy. Moreover, Lesson et al [10] and Antongiovanni et al [13] reported positive beneficial effects of butyric acid on performance traits of broilers.…”

Differential effects of short-chain fatty acids and iron on expression of iha in Shiga-toxigenic Escherichia coli

“…STEC infections result from consumption of contaminated food products and so pathogens may be exposed to SCFAs during food processing, as well as during colonization of the human gut. A number of studies have shown that SCFAs can act as environmental cues, triggering alterations in gene expression, as well as directly inhibiting the growth of pathogenic bacteria (Arnold et al, 2001;Gantois et al, 2006;Kwon & Ricke, 1998;Lawhon et al, 2002;Shin et al, 2002). Variations in SCFA composition in different regions of the gastrointestinal tract (Cummings et al, 1987(Cummings et al, , 2001Cummings & Macfarlane, 1991;Lawhon et al, 2002;Macfarlane et al, 1992) may also enable differential expression of virulence factors in specific host microenvironments.…”