Mouse Model for Pyelonephritis

Abstract

This unit describes a simple way to induce pyelonephritis in female mice using uropathogenic Escherichia coli (UPEC). Methods for culturing and preparing working stocks of UPEC are provided. Protocols to measure the bacterial load in the murine kidney following the establishment of pyelonephritis by determining the bacterial colony forming units (CFU) are also included. This assay can be performed with kidney homogenates if the bacterial load is the sole read-out or if cellular intactness is not required for subsequent assays, or from kidney single cell suspensions prepared by enzymatic digestion. A support protocol describes methods for isolating cells for flow cytometry, ex vivo culture, and other assays.

Cytotoxic Necrotizing Factor 1 Downregulates CD36 Transcription in Macrophages to Induce Inflammation During Acute Urinary Tract Infections

“…For bacterial clearance, Rippere-Lampe reported that CNF1 increased UPEC colonization in bladder and kidney using UPEC clinical strains CP9 and C189 ( 30 ); whereas, Michaud reported that CNF1 had no effect on bacteria colonization using U8 and RS218 ( 32 ); and Diabate reported that CNF1 decreased UPEC in blood while inducing inflammation using UTI89Δ hlyA strain in a bacteremia mouse model ( 31 ). In our study, two widely reported UPEC strains UTI89 (comparing to UTI89Δ cnf1 ) and CFT073 (comparing to CNF1-expressing CFT073) were used to transurethrally infect C57BL/6J mice using a pyelonephritis mouse model ( 35 , 38 ), and found that CNF1 decreased UPEC clearance and increased neutrophil infiltration and tissue damage in bladder and kidney. Based on these published papers and our study, we hypothesized that the effect of CNF1 on bacterial clearance and inflammation were affected by four factors.…”

“…(1) The type of UPEC strain: CNF1 from most UPEC clinical strains except U8 induced inflammation according to our study and others ( 27 – 31 ). (2) The bacterial infection dosage: 10 7 to 2 × 10 9 CFU has been used in urinary tract infection mouse models ( 49 – 52 ), and a high dosage is necessary for kidney infection and CNF1's effect on bacterial clearance ( 30 , 35 , 38 ). In this study, CNF1's effect on bacterial clearance is more obvious by using 10 9 CFU of CFT073 than 10 8 CFU of UTI89.…”

“…Therefore, the inoculation dosage should be different ( 30 , 53 ). (4) The type of tissue: bladder is easily to be colonized by UPEC at a low dosage, whereas kidney infection requires a high dosage ( 35 , 38 ).…”

“…Acute UTIs in mice were established according to the previously described protocols for mouse model for pyelonephritis ( 35 ). UPEC strains were cultured overnight under static conditions in LB medium, harvested by centrifugation at 5000 × g for 10 min, and resuspended in PBS to a concentration of 2 × 10 10 CFU/ml.…”

Animal models of kidney inflammation in translational medicine

“…Infective pyelonephritis process can be mimicked by one-time or repetitive transurethral UPEC inoculation into the urinary bladder of female mice [34]. Transient urethral obstruction with one drop of removable glue supports UPEC entry into the renal pelvis and the onset reliable infective pyelonephritis in all mice [35].…”