Bacterial viability of fecal MCB homogenates.

(a) Quantitative evaluation of bacterial viability in MCB homogenates obtained after immersion of fresh feces of male mice in either M9 or PBS over 28 days. Bacterial viability at day 0 (after feces collection and homogenization) is considered as 100%. Mean ± SEM values. Each data point represents the average of three resazurin assays in technical duplicates. Statistical comparisons by ANOVA repeated measures. (b) Representative images of Schaeffer-Fulton staining (100x) at days 0, 1, 7, 14, 21 and 28. This staining allows the qualitative evaluation of bacterial viability by coloring spores, which are an indicator of viability. Spores are green and bacterial vegetative cells are red—pink. Spores are indicated by an arrow on each image.