A satisfactory mouse model of ascending urinary tract infection (UTI) must avoid inoculation-induced vesicoureteral reflux (VUR) yet still produce kidney and bladder infection in a substantial proportion of mice. To define inoculation conditions that would satisfy both these conditions, mice were evaluated for VUR immediately after inoculation under a variety of conditions and were assessed for kidney and bladder infection 48 h after inoculation. Elimination of VUR required a slowed infusion rate, a reduced inoculum volume (25 μL), and use of less traumatic methods for euthanasia and organ harvest. Bladder and kidney infection were highly prevalent at 48 h among mice inoculated under VUR-free conditions with either of 2 wild type Escherichia coli strains. Together with reports from other investigators, these findings indicate that satisfactory experimental conditions for the mouse model of ascending UTI can be defined empirically but may be laboratory-specific.
Bibliographical noteFunding Information:
Received 3 July 1995; revised 23 October 1995. Animal experimentation guidelines of the University of Minnesota Animal Care Committee were followed in animal studies. Grant support: National Institutes of Health (DK-47504), Minnesota Medical Foundation (MRF-93-93), and University of Minnesota Graduate School (15424). Reprints or correspondence: Dr. James R. Johnson, Medicine/Infectious Diseases, Box 250 UMHC, 14-102 PWB, 516 Delaware St., SE, Minneapolis, MN 55455.