This article describes a method for inducing catheter-associated urinary tract infections (CAUTIs) in a mouse model. The protocol involves catheter implantation and subsequent bacterial inoculation to study the inflammatory response and biofilm formation.
Take a needle and thread it with a piece of polyethylene tubing.
Slide on a piece of silicone tubing, with its soft tip extending beyond the needle’s length.
Attach the needle-tubing assembly to a syringe to complete the catheter.
Place an anesthetized female mouse in a supine position.
Press the abdomen to empty the bladder.
Disinfect the periurethral area with ethanol, followed by povidone-iodine.
Lubricate the catheter tip and insert it transurethrally into the bladder.
Push the polyethylene tubing slightly forward, then withdraw the needle, leaving the silicone catheter inside the bladder.
The implanted catheter causes mechanical irritation and triggers inflammation.
This causes fibrinogen release, which coats the catheter surface.
Inject uropathogenic bacteria into the bladder.
In the bladder, bacterial adhesins bind to the fibrinogen and initiate biofilm formation, resulting in a urinary tract infection (UTI).
This model shows a catheter-associated UTI.
To carry out the CAUTI protocol, begin by cutting a 7-millimeter piece of PE10 tubing and a 5-millimeter piece of silicone tubing, such as RenaSIL. Remove the cap of a 30-gauge needle and use the PE10 tubing to thread the needle up to the base.
Then feed the silicone tubing onto the PE10. To implant the catheter, attach the catheter needle to an empty 1-milliliter syringe. Cut a 1-inch square piece of parafilm and put a dab of surgical lubricant on top.
After anesthetizing the mouse, as mentioned earlier in the video, place the mouse on its back on a paper towel and attach a nose cone to deliver isoflurane. Gently palpate the bladder to induce urination and ensure a voided bladder. Then use a 100% ethanol wipe to clean the periurethral area.
Next, use 10% povidone iodine solution and a cotton-tipped applicator to disinfect the periurethral area. Dab the tip of the inoculation needle into the surgical lubricant, then insert the catheter into the urethral opening. Once in, use tweezers to push the PE tubing toward the bladder, which will deposit the smaller silicone catheter into the bladder. Then immediately remove the needle with the 7-millimeter tubing still attached.
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