One of the most common and inappropriately treated infections in long term care facilities is urinary tract infection. As summarized in the Antibiotic Stewardship and Treatment Guidelines for Long term Care Facilities (published by KFL&A Public Health), below are some of the ongoing issues in the management of urinary tract infection (UTI) in nursing homes:
1. Confirmed UTIs are the commonest infection in LTC and the most common cause for use of antibiotics in LTC.
2. Diagnosis of UTIs in the elderly based on classical signs and symptoms is more difficult. Non-specific and non-localizing signs and symptoms are seldom due to a UTI in a non-catheterized resident.
3. UTIs are the most common source of bacteremia and 40 times more likely to occur in the catheterized resident than non-catheterized resident.
4. Routine screening of asymptomatic residents is NOT necessary. Asymptomatic bacteriuria does NOT require treatment.
5. The renal function of the elderly often decreases and this needs to be considered when selecting the appropriate antibiotic and dose.
So the bottom line is, it is not necessary to treat all positive urine cultures and it depends if it is accompanied by clinical symptoms.
But often the challenge is differentiating symptoms that are related to the infection (e.g. delirium) versus symptoms that are results of other conditions such as dementia (e.g. behaviour and psychological symptoms of dementia).
Aside from this ongoing challenge, my pet peeve is that we don’t always select antibiotics wisely, even with the availability of the C&S report. Escherichia Coli remains one of the most common pathogens responsible for urinary tract infection. Below, I will share some of my thoughts on the selection of antibiotics in treating Urinary Tract infection due to Escherichia Coli:
- The empiric choice of antibiotic often depends on the resistance pattern of the local region as well as the resident’s history of recurrent infection and antibiotic use. If you practice in Eastern Ontario and your resident does not have other complicated risk factors such as diabetes, indwelling catheter and other structural abnormalities, chances are the C&S (Culture and Sensitivity) report would look very similar to one below:
- Often E. Coli is still sensitive to ampicillin and cefazolin! This means you can treat with amoxicillin and cephalexin, respectively. These antibiotics tend to be well tolerated, do not significantly affect INRs and quite forgiving even if dosage adjustment is not done with renal impairment.
- Nitrofurantoin is good too in many cases but avoid in severe renal impairment. Some of the older documents and product monographs indicate nitrofurantoin is contraindicated when CrCL is less than 60mL/min. In reality, we have lots of experiences in using nitrofurantoin when CrCL is less than 60mL/min. However, I will avoid this agent if CrCL is reached below 30mL/min, in which case I may be concerned with toxic metabolites accumulation.
- Fluroquinolones are overly prescribed. These include ciprofloxacin, norfloxacin, levofloxacin and moxifloxacin. I find that when the patient has any documented history of allergies, many physicians are quick to prescribe a fluroquinolone, usually ciprofloxacin. I prefer to avoid using ciprofloxacin unless we have a confirmed urine culture growing pseudomonos aeruginosa. I would also avoid moxifloxacin to treat urinary tract infection because it is not renally eliminated and therefore will not be adequately distributed in the bladder to treat the infection. If treating with a fluroquinolone, will need to watch for interactions with INR for your warfarin patients.
- Septra (AKA co-trimoxazole, Sulfamethoxazole and trimethoprim) has some significant drug interactions. If the pathogen is susceptible to this antibiotic, it certainly is a viable treatment option. However, it can elevate INR significantly. Some clinicians may choose to pre-emptively adjust the warfarin dose, while others may repeat INR in a week to manage the interaction. If the patient is on ACE-inhibitor or ARB for hypertension or other cardiac conditions, Septra can worsen hyperkalemia with potential consequences of sudden cardiac death as described in recent publication. It can happen and the severity of the interaction is often sufficient to consider other agent instead.
- What about ESBL-E Coli (Extended-Spectrum B-Lactamase-Producing Escherichia coli)? This highly resistant pathogen is becoming more prevalent everywhere and can be found in residents with complicated urinary tract infection. Often the choice of antibiotic is limited to the parenteral use of carbapenems such as meropenem or ertapenem, in which case it can be difficult to administer in a nursing home if there is not adequate resources and training in place. There are also challenges due to the short stability of the medication once reconstituted. Often, the clinician should review whether it is indeed a true infection or a matter of colonization which is very common and does not require treatment. If deemed appropriate to treat and the parenteral antibiotic is not an option, we now have fosfomycin which is an oral agent that is covered by Ontario Drug Benefit Program! The studied dose is 3gram given orally every other night for 3 doses.
Urinary tract infection will continue to be the most common infection in long term care facilities. Education is key to recognizing symptoms and diagnosing them quickly and accurately. And if treatment is indicated, we have a number of options available. There is no best agent but many with different pros and cons to be considered.