Infection with pathogenic O157:H7 upregulates ROS.

<p>(A) iHIOs were injected with saline and approximately 10³ commensal <i>E</i>. <i>coli</i> or pathogenic O157:H7. Mean CFU +/- standard error were determined at the indicated times from three different iHIOs for each strain. (B) ROS production was assessed 4 hours post-injection by fluorescence microscopy 30 minutes after addition of the oxidative stress detection reagent (Enzo). Bar indicates 100 μm. (C) Fluorescence intensity, pixels (mean and standard error of the mean) is plotted for three independent iHIOs. Statistical significance was assessed by using one-way ANOVA analysis of variance using Tukey’s multiple comparison posttest using GraphPad Prism 5.0. ** Very significant (<i>P</i> value 0.001 to 0.01), *** extremely significant (<i>P</i> value <i>p</i> < 0.001). Similar results were seen in an independent replicate experiment.