What is the diagnosis for a dialysis patient with persistent bacterial growth in urine and impaired renal function?

Diagnosis: Asymptomatic Bacteriuria

A dialysis patient with persistent bacterial growth in urine without symptoms attributable to urinary tract infection has asymptomatic bacteriuria (ASB), which should NOT be treated with antibiotics. 1, 2

Diagnostic Criteria for ASB in Dialysis Patients

The diagnosis requires specific quantitative thresholds without accompanying UTI symptoms 1, 2:

• For men (including dialysis patients): A single clean-catch voided specimen with ≥10^5 CFU/mL of a single bacterial organism 1, 2
• For women: Two consecutive voided specimens (preferably within 2 weeks) with ≥10^5 CFU/mL of the same organism 1, 2
• For catheterized specimens: ≥10^5 CFU/mL remains the appropriate threshold for bladder bacteriuria; lower counts (≥10^2 to <10^5 CFU/mL) likely represent biofilm contamination rather than true infection 1

Key Clinical Distinction: ASB vs. Symptomatic UTI

The critical determination is whether symptoms are present 1:

Signs of symptomatic UTI requiring treatment 1:

• Fever with systemic signs (chills, fatigue)
• Dysuria, urgency, or urinary frequency
• Flank pain or costovertebral angle tenderness
• New-onset altered mental status with other UTI signs

ASB (no treatment indicated) 1, 2:

• Positive urine culture without any of the above symptoms
• Pyuria alone does NOT indicate need for treatment 1, 2
• Cloudy or malodorous urine alone does NOT indicate symptomatic infection 2

Management Recommendations

Do NOT treat asymptomatic bacteriuria in dialysis patients 1, 2:

• The Infectious Diseases Society of America explicitly recommends against treating ASB in most populations, as it does not reduce morbidity or mortality 1, 2
• Treatment increases antibiotic resistance and eliminates potentially protective bacterial strains 1, 2
• The American Urological Association specifically recommends against screening or treating ASB in patients with indwelling catheters while the catheter remains in place 1, 2

Exceptions requiring treatment 1, 2:

• Pregnant women (screen and treat)
• Patients undergoing urologic procedures with anticipated mucosal bleeding (treat shortly before procedure only)

Important Clinical Pitfalls to Avoid

Do not confuse pyuria with infection 1, 2:

• Pyuria accompanying ASB is NOT an indication for antimicrobial treatment 1, 2
• Dialysis patients commonly have pyuria without infection 1

Do not obtain surveillance urine cultures in asymptomatic patients 1:

• Screening asymptomatic neurogenic lower urinary tract dysfunction (NLUTD) patients is explicitly not recommended 1
• This principle extends to dialysis patients who are asymptomatic 1

Only obtain urine culture when symptoms suggest UTI 1:

• In patients with signs and symptoms suggestive of UTI, obtain urinalysis and urine culture 1
• For catheterized patients with suspected UTI, obtain culture after changing the catheter and allowing urine accumulation while plugging the catheter—never from extension tubing or collection bag 1

When to Pursue Further Evaluation

If truly symptomatic UTI with rapid recurrence or bacterial persistence 1:

• Recurrence within 2 weeks of treatment or bacterial persistence without symptom resolution suggests complicated infection 1
• Evaluate for structural abnormalities: calculi, foreign bodies, urethral/bladder diverticula, infected cysts 1
• Consider imaging (CT urography) and cystoscopy to identify treatable anatomic causes 1

For febrile UTI in dialysis patients 1:

• Order upper tract imaging if patient does not respond appropriately to antibiotics 1
• Evaluate for stones, hydronephrosis, or abscess formation 1