Why does catheterization procedure matter for infection model consistency?

Standardized catheterization ensures reproducible bacterial delivery to the bladder lumen, minimizing variability in infection establishment across animals.

How does α-hemolysin toxin enable bacterial escape from vesicles?

α-hemolysin toxin monomers assemble into pore complexes in the vesicular membrane, allowing bacteria to translocate into the host cytoplasm for replication.

What quantifies intracellular bacterial community formation in this model?

IBC formation is assessed by microscopy or bacterial enumeration from bladder homogenates, reflecting intracellular replication and biofilm-like aggregation.

Why is infection progression monitored over time in male mice?

Tracking bacterial dissemination from IBCs to neighboring cells helps evaluate therapeutic impact on infection spread and persistence.

What statistical thresholds define successful infection establishment?

Infection success is determined by predefined instillation quality scores and post-inoculation bacterial load measurements above background levels.

Transurethral Catheterization and Bacterial Inoculation to Generate a Urinary Tract Infection Model in Male Mice

JoVE Encyclopedia of Experiments

Immunology

0 views • 2:32 min • July 8th, 2025

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Take an anesthetized male mouse and insert a catheter into its genitalia.

Introduce uropathogenic bacteria into the urethra. Inside the urinary tract, the bacterium attaches to the uroepithelial cell.

The interaction of bacterial surface proteins with host cell membrane proteins induces cytoskeletal rearrangement causing the host cell membrane to tightly wrap around the bacterium through a zipper mechanism.

The bacterium is subsequently internalized within a membrane-bound vesicle. Within the vesicle, the bacterium produces α-hemolysin toxin monomers which assemble to form a pore complex in the vesicular membrane.

The bacterium escapes through the pore complex into the host cell cytoplasm where it replicates to form intracellular bacterial communities, or IBCs. IBCs are dense, biofilm-like structures within host cells, protected from direct attack by immune cells present in the extracellular space.

As the uropathogenic bacteria mature within IBCs, they eventually exit the host cells to infect neighboring cells, causing urinary tract infections.

To inoculate male mice, place two thumb forceps cranially and caudally to the mouse's external genitalia. Retract the prepuce to fully expose the glans penis. Then, once the penis is externally positioned, release the thumb forceps. Reposition the forceps to stabilize the protruding penis perpendicular to the animal, holding the organ gently but tautly. Then, through the small opening in the tip of the urethral meatus, carefully introduce the catheter and gently guide it into the penis using forceps to gently maintain tension.

Once the hub of the catheter meets the tip of the penis, very slowly, dispense 50 microliters of the inoculum while maintaining the position of the penis. Note the quality of the instillation according to a predetermined instillation quality score, such as the one shown here. Retract the catheter slowly over 5 seconds to prevent leakage of the inoculum. Place the mouse in its cage in a supine position. The animal should begin to recover 30 to 45 minutes following administration of the anesthetic.