Sometimes patients can't urinate due to injury, surgery or other reasons. When that happens, a nurse or doctor may install a catheter that automatically drains urine from the person's bladder. One end of the tube goes through the skin and into the bladder; the other end attaches to a collection bag.
The problem is that the bladder and urinary tract are usually germ-free environments, and introducing an external tube can allow pathogens to get into the bladder and cause a UTI, the most common hospital-acquired infection.
These illnesses are often caused by common bacteria found in your intestines, on your skin, or in your mouth and nose. Escherichia coli and Klebsiella are potential culprits. When they get into the urinary tract, however, there are no other bacteria there to keep them in check, so they multiply quickly and cause an infection. Symptoms can include pain or difficulty urinating, excessively frequent urination (after the catheter is removed), fever, a painful lower abdomen or bloody urine [source: George Washington University Hospital].
The procedures for preventing catheter UTIs are similar to most hospital-acquired infections – thorough hand-washing by hospital workers, using soap and alcohol gel, plus carefully maintaining sterile conditions in the catheter itself, which should be removed as soon as possible. Other techniques include temporary catheters that are only in place while the bladder is being drained, as well as external catheters for male patients that don't introduce anything into the bladder or urinary tract [source: CDC].