INS and irritable bowel syndrome: S. wadsworthensis protects against IBD (Wexler et al., 1996); C. catus ferments fructose, lactate, and pyruvate to short-chain fatty acids (SCFAs) (Holdeman and Moore, 1974); E. hallii contributes to the intestinal propionate formation (Engels et al., 2016) and improves insulin sensitivity (Udayappan et al., 2016); E. ramulus produces propionic acid and dihydroxyphenylacetic acid (Schneider and Blaut, 2000; Braune et al., 2001); R. obeum plays an important role in the recovery process from Vibrio cholerae infection (Lawson and Finegold, 2015).