Indwelling Urinary Catheter

A catheter-associated urinary tract infection (CAUTI) develops when organisms gain access to the urinary tract along the outside or inside of an indwelling catheter. The catheter surface provides a place for bacteria to adhere and form a biofilm, a protective layer that makes organisms harder to remove and more difficult to treat with antimicrobials. The longer a catheter remains in place, the greater the opportunity for colonization. Gram-negative bacilli such as Escherichia coli are common causes, but the prevention principle is broader: every unnecessary catheter day creates another day of infection risk. A closed drainage system is meant to keep organisms out. Disconnecting tubing, allowing urine to pool in dependent loops, or placing the drainage bag above bladder level can defeat that protection. Urine can then stagnate or reflux toward the bladder, carrying organisms with it.