Intracellular bacterial communities (IBC) in urinary bladder transitional epithelial cell and gall bladder mucosal epithelium. Female C57BL/6 mice were challenged by intra-urethral inoculation with 107 CFUs human urinary pathogenic E. coli strain UTI89 and its bladder was harvested 24 h after infection. Whole mounts of urinary bladder were stained with cytox orange (light green in A), DAPI (blue in A) and WGA (false colored dark green in A). A single Z-section obtained by confocal laser microscopy demonstrates a large aggregation of intracellular bacterial community (IBC) in superficial umbrella bladder epithelial cell (arrow in A). Female C57BL/6 mice were challenged by injection of 105 CFUs of Salmonella enterica serovar Typhimurium/PoxyS-gfp strain SL1344 into the gall bladder which was harvested 24 h after infection. Whole mounts of gall bladder were stained with DAPI (blue in B) and phalloidin-TRITC (red in B). A single Z-section obtained by confocal laser microscopy demonstrates IBC of GFP-expressing bacteria in gall bladder epithelial cells. Scale bars 20 µm (A) and 50 µm (B). All images are representative of the entire sample. The histological morphology and pathology results were very similar for each organ in a given mouse and between mice.