What causes urinary tract infection with the urinary catheter

Urinary catheter is a medical device used primarily to help patients who are unable to urinate independently. It is inserted into the bladder through the urethra or abdominal stoma and is suitable for temporary or long-term use in situations such as postoperative recovery, urinary retention, monitoring urine output, or prolonged bed rest. While its role is significant, strict aseptic technique must be followed to reduce the risk of infection. There are many reasons why urinary tract infections can occur with urinary catheters, including the following:

Lax aseptic operation: During the catheterization process, if the aseptic operation specifications are not strictly followed, such as failure to prepare the skin, incomplete disinfection of the urethral opening, or insufficient disinfection range, exogenous bacteria may be introduced into the urethra and bladder, thereby causing urinary tract infection.

Prolonged urinary catheterization: Generally, a urinary catheter should be left in place for 3-7 days. If it is left in place for an extended period, the catheter should be changed every 7-10 days. Prolonged urinary catheterization not only increases the risk of urinary tract infections (UTIs), but can also block urine secretion, leading to urinary tract infections such as acute urethritis. Furthermore, the risk of infection increases significantly if a urinary catheter is left in place for more than two weeks.

Improper urinary catheter care: After indwelling catheterization, care measures such as bladder irrigation and urethral disinfection are required. If these care measures are not carried out in a timely and effective manner, bacteria may grow around the urinary catheter, leading to urinary tract infection.

Disruption of urinary tract seals: The placement of an indwelling catheter disrupts the urinary tract's seal, making it easier for bacteria to invade the urinary tract. Furthermore, if the urine drainage system is not properly sealed, or if the urine bag is positioned higher than the bladder, contaminated urine may flow back into the bladder, leading to a urinary tract infection.

Catheter irritation and friction: During indwelling, a catheter can irritate and abrade the urethral mucosa, potentially weakening its defenses and making it easier for bacteria to invade and cause infection.

Biofilm infection: Urinary substances may deposit on the surface of the urinary catheter, forming a thin film that facilitates bacterial colonization and resists antibiotic treatment. Once attached to the catheter, bacteria secrete extracellular matrix to form a biofilm, further exacerbating the infection.

Encrustation: When urease-producing bacteria adhere to the urinary catheter, they gradually form a catheter encrustation. This encrustation not only leads to poor drainage and obstruction but also can exacerbate the progression of catheter-related infections.

Catheterization can cause urinary tract infections (UTIs) due to multiple factors, including lax aseptic technique, prolonged catheterization, improper catheter care, compromised urinary tract closure, catheter irritation and friction, biofilm infection, and encrustation. To prevent UTIs, healthcare professionals should strictly adhere to aseptic technique, manage catheterization duration, ensure adequate catheter care, maintain urinary tract closure, and closely monitor changes in the patient's condition.