We employed a model of UPEC-induced cystitis in which 107 colony-forming units (CFU) of UPEC isolate UTI89, made resistant to either ampicillin or kanamycin, were instilled intravesically into 7–8 week old female wildtype C57Bl/6 or C57Bl/6 RAG2-/- mice [20]. Here, RAG2 is linked to chronic cystitis.