Fig. 6

Colonization of the mouse intestine by EcN and EcNsat::cat. a Two sets of four mice were fed independently with 2x10⁵ CFU of strain EcN Sm^r Rf^r (squares) or the mutant strain EcNsat::cat Sm^r Rf^r Cm^r (triangles). b Competition experiments: One set of four mice were fed with 2x10⁵ CFU of a mixture (1:1) of strains EcN Sm^r Rf^r (squares) and the mutant strain EcNsat::cat Sm^r Rf^r Cm^r (triangles). Three independent biological assays were performed for these competition experiments (total n = 12). At the indicated times, stool samples were collected and processed for bacterial counting. Results are expressed as Log₁₀ CFU/g stool (left panels). At day 18, mice were sacrificed and sections from ileum and colon were removed from each mouse. The mucus layer from each fragment was scraped, homogenized and processed for bacterial quantification. Results, expressed as CFUx10⁴/g of mucus, were the mean ± SE of the three independent biological assays (right panels). Asterisks indicate values significantly different from that of the parental strain EcN (*p < 0.05, **p = 0.000)