Figure 1

Experimental design of continuous three-stage colonic fermentations. Two three-stage continuous fermentation models (F1 and F2) simulating (R1) proximal, (R2) transverse and (R3) distal colonic sections were inoculated with the same immobilized child fecal microbiota, infected with Salmonella beads and operated in parallel for a total of 65 days divided into different experimental periods as described previously [15]. For this study, reactor effluents collected during the last 3 days of each experimental period were directly applied onto confluent mucus-secreting HT29-MTX cell layers to detect host-protection properties of different experimental treatments. Data obtained during similar treatments in models F1 and F2 (highlighted in the same color) were not significantly different and therefore used as repetitions: (Stab) initial system stabilization periods, (Sal) Salmonella infection periods, (Ecol) E. coli L1000 wt treatments (microcin B17-producing wild-type strain), (Ecol*) E. coli L1000 MccB17- treatments (microcin B17-negative mutant strain), (Bif) B. thermophilum RBL67 treatments, (Inulin) prebiotic inulin treatment.