is Well Adapted to Withstand Intestinal Stressors and Modulate the Gut Epithelium.

The gastrointestinal tract has been speculated to serve as a reservoir for , however little is known about the ecological fitness of strains in the gut. Likewise, not much is known about the ability of to consume dietary, or host derived nutrients or their capacity to modulate host gene expression. Given the increasing prevalence of in the clinical setting, we sought to characterize how responds to gut-related stressors and identify potential microbe-host interactions. To accomplish these aims, we grew clinical isolates and commercially available strains of in minimal media with different levels of pH, osmolarity, ethanol and hydrogen peroxide. Utilization of nutrients was examined using Biolog phenotypic microarrays. To examine the interactions of with the host, inverted murine organoids where the apical membrane is exposed to bacteria, were incubated with live and gene expression was examined by qPCR. All strains grew modestly at pH 6, 5 and 4; indicating that these strains could tolerate passage through the gastrointestinal tract. All strains had robust growth in 0.1 and 0.5 M NaCl concentrations which mirror the small intestine, but differences were observed between strains in response to 1 M NaCl. Additionally, all strains tolerated up to 5% ethanol and 0.1% hydrogen peroxide. Biolog phenotypic microarrays revealed that strains could use a range of nutrient sources, including monosaccharides, disaccharides, polymers, glycosides, acids, and amino acids. Interestingly, the commercially available strains and one clinical isolate stimulated the pro-inflammatory cytokines , , and while all strains suppressed and . Collectively, these data demonstrate that is well adapted to dealing with environmental stressors of the gastrointestinal system. This data also points to the potential for to influence the gut epithelium.