Fig. 2

Dynamics of ETEC survival in different gastrointestinal regions of the TIM-1 and M-SHIME systems. a After introduction of a glass of ETEC-contaminated water in the TIM-1 stomach, the number of cultivable ETEC cells in each compartment was determined by plate counts. Results are expressed as mean concentrations in log₁₀ CFU mL⁻¹ ± SD of four independent replicates (red line), compared with an inert and non-absorbable transit marker indicating 100% survival (gray dashed line). Bacterial curves below that of the transit marker reflect cell mortality, while curves above the transit marker are indicative of bacterial growth. The level of pH in each compartment is illustrated in green. No statistical significant differences were found between ETEC and transit marker kinetics. b After gastro-jejunal digestion of a glass of ETEC-contaminated water under static batch, the pre-digested ETEC inoculum was introduced in the M-SHIME ileum at day 13 and followed up till 122 h post-infection in the luminal and mucosal phases of the ileum and ascending colon. ETEC survival was estimated by qPCR and expressed in log₁₀ gspD copy number mL⁻¹ ± SD of six different healthy donors. Statistically significant differences between ETEC survival in the luminal vs the mucosal phases are denoted at p < 0.05 (*), as determined by pairwise Wilcoxon rank sum tests with Holm correction