Fig 6.

Acetate, butyrate, and lactate fermenters in the gut microbiota. (A) Relative proportions of acetate, butyrate, and lactate fermenters in the gut microbiota in the CDI (red), CDN (yellow), and HC (green) cohorts pyrosequenced. Sequence reads were classified at the genus level according to the primary metabolic end product of carbohydrate fermentation, and results were compared using Student's t test. Genera that were ambiguously defined as producing both acetate and butyrate or other short-chain fatty acids, such as succinate, propionate, formate, or ethanol, comprising minor constituents of the gut microbiota (<1% of sequence reads), were excluded in this analysis. Error bars, standard error of the mean. ∗, P < 0.05; ∗∗, P < 0.01; ∗∗∗, P < 0.001. CDI, C. difficile infection; CDN, C. difficile-negative nosocomial diarrhea; HC, healthy control; NS, not significant. (B) Relative proportions of major butyrate-producing bacteria. (C) Relative proportions of major acetogens by genera. (D) Relative proportions of primary lactic acid-producing organisms.