Generating Urinary Tract Infection Model: A Technique to Administer Uropathogenic Bacteria in Mouse to Develop Urinary Tract Infection Model

Urinary tract infection, or UTI, is primarily caused by the colonization of uropathogenic E. coli bacteria in the kidneys, ureters, bladder, or urethra.

To generate a UTI murine model, begin by placing an anesthetized mouse in the supine position. Using a stereomicroscope, visualize the mouse’s lower abdominal region to locate the deep pink urethral opening.

Now, take a syringe containing the desired uropathogenic bacterial solution with an angiocatheter tip attached to it. Insert the catheter perpendicularly into the urethra. Tilt the syringe to position it horizontally, and push it further until it reaches the urinary bladder.

Then, slowly instill the bacterial inoculum into the bladder. Maintain the syringe and catheter in place for the desired duration to prevent leakage. Retract the catheter slowly from the urethra and allow the bacteria to proliferate.

Once inside, the bacterial population invades the superficial bladder epithelial cells, where they replicate to form intracellular bacterial communities, or IBCs, in the cytoplasm of these cells.

Eventually, these bacteria release into the bladder lumen, where they infect the nearby cells, causing the spread of infection.

The UTI murine model is now ready for further downstream analysis.

Mount a sterile 24-gauge angiocatheter tip on a 100-microliter syringe. Fill the syringe with the prepared bacterial solution. Place one animal on a working surface in the supine position, and maintain a stable isoflurane anesthesia, using a nose cone during the instillation. Apply the eye ointment. Expel the residual urine by applying gentle compression, and making circular movements on the suprapubic region. Then, clean the lower abdomen with 70% ethanol.

Lubricate the catheter tip with normal saline. Put the index finger of the non-dominant hand on the abdomen and push it gently upwards. Start the catheterization of the urethra vertically in a 90-degree angle. Once resistance is encountered, tilt it horizontally before inserting it further. Perform a slow instillation of 50 microliters of the bacterial inoculum. After the instillation, keep the syringe and catheter in place for a few more seconds, and then slowly retract to prevent leakage.