Do we need to treat asymptomatic positive urine cultures in elderly people?

Management of Asymptomatic Bacteriuria in Elderly People

Screening for and treatment of asymptomatic bacteriuria in elderly people is not recommended, regardless of whether they live in the community or in long-term care facilities. 1

Definition and Prevalence

• Asymptomatic bacteriuria (ASB) is defined as the isolation of a specified quantitative count of bacteria in an appropriately collected urine specimen from a person without symptoms or signs referable to urinary infection 1
• For asymptomatic women, bacteriuria is defined as 2 consecutive voided urine specimens with isolation of the same bacterial strain in quantitative counts ≥10^5 cfu/mL 1
• For men, a single clean-catch voided urine specimen with 1 bacterial species isolated in a quantitative count ≥10^5 cfu/mL identifies bacteriuria 1
• ASB is common in elderly populations, occurring in 25-50% of elderly nursing home residents 2

Evidence Against Treatment in Elderly Populations

Community-Dwelling Elderly

• Multiple studies show no benefits from screening for or treating ASB in older persons living in the community 1
• A prospective cohort study of 134 ambulatory male veterans >65 years of age observed for 1-4.5 years reported no adverse outcomes attributable to untreated bacteriuria 1
• Population-based cohort studies show no association between bacteriuria and survival for elderly men and women during 5 years of follow-up 1
• In a controlled clinical trial, antibiotic therapy effectively reduced the subsequent occurrence of positive urine cultures in older ambulatory women, but symptoms were not reduced, suggesting treatment is contraindicated 3

Institutionalized Elderly

• Prospective, randomized clinical trials of antimicrobial therapy versus no therapy for elderly residents of long-term care facilities have consistently shown no benefits of screening for or treatment of ASB 1
• There was no decrease in the rate of symptomatic infection or improvement in survival associated with antimicrobial therapy 1
• Treatment of ASB was associated with significantly increased adverse antimicrobial effects and reinfection with organisms of increasing resistance 1
• Prospective cohort studies report similar survival data for long-term care facility residents with and without bacteriuria 1

Special Considerations in Elderly Patients

Cognitive Impairment and Delirium

• In older patients with functional and/or cognitive impairment with bacteriuria and delirium (acute mental status change, confusion) without local genitourinary symptoms or other systemic signs of infection, assessment for other causes and careful observation rather than antimicrobial treatment is recommended 1
• Similarly, in elderly patients who experience a fall with bacteriuria but without urinary symptoms or systemic signs of infection, assessment for other causes rather than antimicrobial treatment is recommended 1

Catheterized Patients

• For patients with indwelling catheters, ASB should not be treated while the catheter remains in place 1
• In patients with long-term indwelling urethral catheters, the presence of bacteriuria and pyuria is virtually universal and does not require treatment unless there are signs of systemic infection 1
• For patients with suspected urosepsis (fever, shaking chills, hypotension), urine and blood cultures should be obtained and catheters should be changed prior to starting antibiotics 1

Diagnostic Considerations

• Urinalysis and urine cultures should not be performed for asymptomatic residents 1
• The diagnostic evaluation of suspected UTI should be reserved for those with acute onset of UTI-associated symptoms and signs (fever, dysuria, gross hematuria, new or worsening urinary incontinence, and/or suspected bacteremia) 1
• Pyuria accompanying ASB is not an indication for antimicrobial treatment 1
• The presence of bacteria in urine without localizing urinary tract signs or symptoms should not be treated with antibiotics 4

Implementation Strategies

• Educational interventions for healthcare providers can help reduce inappropriate treatment of ASB in long-term care facilities 5
• Development of clinical pathways to help nurses and other care providers better assess, manage, and monitor residents with suspected UTIs can decrease the number of inappropriately treated ASB cases 5
• Management strategies to decrease negative impact of culturing urine include: preventing urine testing in patients with extra-urinary tract reasons for their acute care, canceling urine cultures if the urine dipstick is negative, and avoiding catheterization in stable patients who cannot provide a urine specimen on demand 4

Exceptions to Non-Treatment Recommendations

While ASB in the elderly generally should not be treated, there are specific clinical scenarios where screening and treatment are recommended:

• Before transurethral resection of the prostate or other urologic procedures where mucosal bleeding is anticipated 1
• In pregnant women (not applicable to elderly population) 1
• Antimicrobial treatment of asymptomatic women with catheter-acquired bacteriuria that persists 48 hours after indwelling catheter removal may be considered 1

By following these evidence-based recommendations, clinicians can avoid unnecessary antibiotic use, prevent antimicrobial resistance, and reduce adverse drug effects in elderly patients.