So an elderly gentleman comes into the department. He lives in a care home, he has a catheter, and he’s got a mild pyrexia, slightly more muddled than normal and some suprapubic tenderness. After a full assessment you decide he has a Catheter Associated UTI (CA-UTI).
Your hospital policy suggests treating based on a previous culture growths and discussion with a microbiologist. After a short discussion you get a code and prescribe an appropriate antibiotic.
You are just preparing to change the catheter when a senior colleague suggests you should also ‘give a shot of Gent’ to cover the change.
People who have a long term catheter (LTC) will have asymptomatic bacteriuria. All catheters become colonised with organisms that produce biofilms. This biofilm acts as a reservoir for bacteria, and it needs to be removed if someone is symptomatic. You do that by changing the catheter.
In some respects I can understand the rationale for giving gentamicin to someone in this situation. You want to reduce the amount of bacteria left in the bladder to limit the formation of a new biofilm on your shiny new catheter.
However evidence that this is what we should do is lacking.
SIGNs guidance on suspected bacterial UTI in adults states that “In a hospital setting, when prophylaxis for catheter change is required, consider using a narrow spectrum agent such as gentamicin rather than ciprofloxacin to minimise the risk of C difficile infection”. It states this is a category C recommendation (low quality). It has one reference to back it up, which is the 2009 guidelines for CAUTI from the Infectious Diseases Society of America.
These guidelines do not recommend the use of prophylactic antibiotics for catheter change. They do recommend changing the catheter in CAUTI, but say nothing about the incredibly common situation described above.
Now the evidence they cite does suggest that giving antimicrobials does decrease the number of people with asymptomatic bacteriuria, however that response is transient, and does lead to resistance. I think you can probably argue either way that in our situation (man with CA UTI) we may want to decrease the amount of free bacteria in the urine as much as possible. However if you’ve taken appropriate microbiological advice the systemic therapy you have started should be enough to do just that.
They other justification I would suppose would be that instrumentation of the urethra might lead to a transient bacteriuria. However in the one study of community catheter changes they quote (Jews et al) the bacteraemia was transient, and asymptomatic. They then go on two discuss 3 RCTS comparing prophylaxis for catheter change and though each one showed a reduction in amount of bacteriuria in the prophylaxis groups the rates if bacteriuria equilibrated after 2 weeks.
I ran through a quick pubmed search for catheter associated UTI and of the 369 papers it threw back at me none seemed to look at this specific issue. The guidance from SIGN on this specific thing, is based on the Infectious Diseases Society of America guidance, but does seem to draw a slightly different conclusion. NICE draws its guidance from SIGN and suggests that prophylaxis should only be given if there is trauma during insertion or if the patient has a history of post-change CA-UTI.
So I think I’ll be leaving the Gent in the cupboard on this occasion.
Hooton, Thomas M., et al. “Diagnosis, prevention, and treatment of catheter-associated urinary tract infection in adults: 2009 International Clinical Practice Guidelines from the Infectious Diseases Society of America.” Clinical infectious diseases 50.5 (2010): 625-663. [available here]
Beveridge LA, Davey PG, Phillips G, McMurdo ME. Optimal management of urinary tract infections in older people. Clinical Interventions in Aging. 2011;6:173-180. doi:10.2147/CIA.S13423. [available here]