Fecal densities. Concentration of L. monocytogenes in fecal samples of animals dosed with un-restricted (open symbols) and/or oxygen-restricted (closed symbols), fluorescence-labeled bacteria. (A): Animals dosed with monocultures of CFP-labeled bacteria. (B): Integrated presentation of data from C and D. (C): Animals dosed with a mixture of CFP-labeled, un-restricted Listeria and YFP-labeled, oxygen-restricted Listeria. (D): Animals were dosed with a mixture of YFP-labeled, un-restricted Listeria and CFP-labeled, oxygen-restricted Listeria. All animals were dosed at Day 0 and again at Day 1. Each data point in panel A and B represents the average of samples from 12 animals, while each data point in panel C and D represents the average of samples from 6 animals. Error bars designate standard errors of the means.