What is the recommended treatment for asymptomatic Klebsiella pneumoniae in a urine culture for a 71-year-old man?

Treatment of Asymptomatic Klebsiella pneumoniae Bacteriuria in a 71-Year-Old Man

Do not treat asymptomatic bacteriuria with antibiotics in this patient. The most recent and highest quality evidence from the 2019 IDSA guideline explicitly recommends against screening for or treating asymptomatic bacteriuria in older adults, as treatment provides no clinical benefit and causes significant harm 1.

Evidence-Based Rationale

Strong Recommendation Against Treatment

• The 2019 IDSA guideline provides a strong recommendation (A-I level evidence) against treating asymptomatic bacteriuria in older adults living in the community 1.
• The 2005 IDSA guideline similarly recommends against treatment in premenopausal, nonpregnant women, diabetic women, older community-dwelling persons, elderly institutionalized subjects, and catheterized patients while the catheter remains in place (all A-I recommendations) 1.
• Treatment of asymptomatic bacteriuria does not reduce mortality, prevent symptomatic UTI, or improve functional outcomes in older adults 1.

Documented Harms of Treatment

• Antimicrobial treatment of asymptomatic bacteriuria significantly increases the risk of Clostridioides difficile infection (CDI), with delirious patients treated for asymptomatic bacteriuria showing an odds ratio of 2.45 for developing CDI 1.
• Treatment increases antimicrobial resistance for the individual patient, the institution, and the community 1.
• Antibiotic-associated diarrhea and other adverse drug effects occur without any offsetting clinical benefit 1.

Clinical Context for This Patient

Definition of Asymptomatic Bacteriuria

• Asymptomatic bacteriuria is defined as isolation of a specified quantitative bacterial count in an appropriately collected urine specimen from a person without symptoms or signs referable to urinary infection 1.
• The absence of dysuria, frequency, urgency, suprapubic pain, fever, costovertebral angle tenderness, or systemic signs of infection confirms this is asymptomatic bacteriuria 1.

When to Consider Treatment (Exceptions)

Treatment would only be indicated if the patient develops:

• Acute onset of UTI-associated symptoms (fever, dysuria, gross hematuria, new or worsening urinary incontinence) 1.
• Signs of urosepsis (fever, shaking chills, hypotension, or delirium with hemodynamic instability) 1.
• Classic localizing genitourinary symptoms with systemic signs of infection 1.

Common Pitfalls to Avoid

Do Not Treat Based on:

• Mental status changes alone - Studies show no improvement in delirium severity or duration with treatment of asymptomatic bacteriuria, and treatment is associated with worse functional outcomes (adjusted OR 3.45 for poor functional outcome) 1.
• Pyuria on urinalysis - Pyuria commonly accompanies asymptomatic bacteriuria in older adults and does not indicate need for treatment 1.
• Positive urine culture results alone - Up to 40% of institutionalized elderly women have asymptomatic bacteriuria 2.
• Falls or non-specific symptoms - These are not indications for urine culture or treatment in the absence of localizing genitourinary symptoms 1.

Catheter Considerations

• If this patient has an indwelling urinary catheter, do not treat asymptomatic bacteriuria while the catheter remains in place (A-I recommendation) 1.
• The case report in the evidence demonstrates that asymptomatic catheter-associated bacteriuria with carbapenem-resistant K. pneumoniae resolved after catheter replacement without antibiotic therapy 1.
• Consider catheter removal if feasible, as this may resolve bacteriuria without antibiotics 3, 2.

Monitoring Approach

Instead of treating, implement the following strategy:

• Monitor clinically for development of symptoms suggesting symptomatic UTI 1.
• Educate the patient and caregivers about symptoms that would warrant re-evaluation (fever, dysuria, flank pain, altered mental status with fever) 1.
• Do not perform repeat urine cultures in the absence of symptoms 1.
• If an indwelling catheter is present and has been in place >2 weeks, consider replacement if clinically indicated for other reasons 3.