All positive Urine Cultures in a catheterised patient do not require antibiotic therapy
Infection vs Bacterial Colonisation
There is a difference between shedding of bacteria in urine (bacteriuria) and actual urine infection.
In a catheterised patient, mere presence of bacteria in urine which is shown as a positive urine culture report without any urinary symptoms or change in urinary symptoms is usually not infection. After catheterisation the probability of getting positive urine culture increases by 10% every day. In effect, by 10th day urine of all the catheterised patients will grow bacteria on culture but that does not mean infection. that is pure shedding of bacteria. These bacteria grow on the catheter from the skin of the genitals at the entry point of catheter and move upto the bladder.and simply (and peacefully!) occupy the inner surface of the bladder as they were always present on the skin. They are harmless till they are not penetrating the smooth inner lining of the bladder called mucosa. It is then that the bladder recognises them as enemy and starts reacting to them with a process called inflammation (similar to redness on the skin after a scratch or an abrasion). This can happen if the catheters get blocked for prolonged hours and there are higher pressures in the bladder or if they get favourable conditions to multiply.
When actual infection happens, it generally does not remain silent. It will trouble the body and may cause pain, leakage of urine around the catheter (called peri-catheter leak), change in color of urine to turbid and dirty or fever associated with some of these symptoms. Such conditions should prompt the physician to start antibiotic therapy.
Chasing every positive urine culture with antibiotics is futile and will give rise to infection with more aggressive bacteria which will be resistant to antibiotics already used.
Good practices for catheter care in patients on catheter
Do not use any antibiotic cream around entry point of urinary catheter. Applying antibiotics there prevents the usually harmless skin bacteria to enter but at the same time give opportunity to more aggressive resistant bacteria to enter the bladder. Simple catheter cleaning with soap and water till the entry point is recommended.
Do not disconnect the Urobag from the catheter as it is meant to maintain a closed system of drainage
Keep the catheter and the urobag tube free from all kinks that could prevent free drainage
Open the lid of the Urobag only while emptying the bag and keep it closed at all other times
Instillation of antibiotic solutions in bladder or urobag are NOT recommended