Urine and Tissue Bacterial Loads Correlate With Voiding Behaviors in a Murine Urinary Tract Infection Model

Area of Science:

• Urology
• Infectious Diseases
• Microbiology

Background:

• Urinary tract infections (UTIs) are common, often caused by uropathogenic Escherichia coli (UPEC).
• Understanding the relationship between bacterial load and host voiding behavior is crucial for managing chronic UTIs.
• Murine models are essential for studying UTI pathogenesis and host-pathogen interactions.

Purpose of the Study:

• To investigate the association between voiding behavior and bacterial loads in a murine model of urinary tract infection (UTI).
• To determine how bacterial presence and load impact urinary frequency, volume, and bladder capacity.
• To explore potential correlations between chronic infection markers and altered micturition patterns.

Main Methods:

• Female C57BL/6J mice were infected with UPEC UTI89 via transurethral inoculation.
• Voiding spot assays were employed to quantify voiding behavior at multiple time points post-infection (dpi).
• Urine, bladder, and kidney bacterial loads were assessed, alongside histological examination for chronic changes.

Main Results:

• Infected mice exhibited increased urinary frequency, polyuria, and reduced bladder capacity.
• Urinary and tissue bacterial loads at 1 and 28 dpi were positively correlated with increased urinary frequency and polyuria.
• Chronic cystitis and pyelonephritis developed in a significant proportion of infected mice, with observed bladder tissue fibrosis.

Conclusions:

• Bacterial loads in urine and tissues are directly associated with altered voiding behaviors in a murine UTI model.
• These findings highlight the impact of UPEC infection on bladder function and suggest a link between bacterial burden and micturition changes.
• The study provides insights into the pathophysiology of chronic UTIs and their effect on lower urinary tract symptoms.