Epifluorescence micrograph of the murine urinary bladder epithelium during chronic bacterial cystitis with uropathogenic E. coli (UPEC). The image demonstrates the ongoing bladder epithelial inflammation (epithelial and immune cell nuclei are counterstained blue and epithelial cells autofluoresce green) after 4 weeks of UPEC infection. Bacteria appear yellow-orange due to indirect antibody co-staining with anti-E. coli (red) and anti-FimH for type 1 pili (green). Persistent extracellular colonization of the bladder with UPEC and accompanying chronic inflammatory responses induce changes to the bladder wall that persist long after clearance of infection with antibiotics and leave mice vulnerable to severe recurrent UTI (see Hannan et al., doi:10.1371/journal.ppat.1001042).

Image Credit: Thomas J. Hannan, Washington University