What is the appropriate treatment for a urinary tract infection in an adult on chronic hemodialysis?

UTI Treatment in Hemodialysis Patients

For adult hemodialysis patients with symptomatic UTI, obtain urine culture before initiating empiric therapy with trimethoprim-sulfamethoxazole 160/800 mg once daily (adjusted for dialysis schedule) or a fluoroquinolone such as levofloxacin 250 mg once daily for 7-10 days, then adjust based on culture results and local resistance patterns. 1, 2

Critical First Steps

• Obtain urine culture before starting antibiotics to guide definitive therapy, as hemodialysis patients have higher rates of resistant organisms 1, 2
• Distinguish symptomatic UTI from asymptomatic bacteriuria (ASB), which is present in 28% of hemodialysis patients and should NOT be treated 3
• Do not treat ASB in dialysis patients - it provides no clinical benefit and promotes antimicrobial resistance 3

Empiric Antibiotic Selection Algorithm

First-Line Options (if local resistance <20%):

• Trimethoprim-sulfamethoxazole (TMP-SMX): 160/800 mg once daily (given after dialysis on dialysis days) 1, 2
• Fluoroquinolones: Levofloxacin 250 mg once daily (dose-adjusted for renal failure) 1, 4

Alternative Options:

• Ceftriaxone: 1-2g IV daily for severe infections requiring hospitalization (no dose adjustment needed for dialysis) 2, 5
• Ertapenem: 500 mg IV once daily for complicated UTI with resistant organisms (dose-adjusted for dialysis patients) 5

Avoid These Agents:

• Nitrofurantoin: Contraindicated in dialysis patients due to inadequate urinary concentrations and risk of toxicity 4, 6
• Fosfomycin: Inadequate data for dosing in dialysis patients 4, 7

Treatment Duration

• Uncomplicated cystitis: 7-10 days 1, 2
• Complicated UTI or pyelonephritis: 10-14 days, depending on clinical response 2
• Catheter-associated UTI: 7 days for prompt response, 10-14 days for delayed response 2

Special Considerations for Dialysis Patients

Dosing Adjustments:

• Administer antibiotics after dialysis sessions when possible, as most UTI antibiotics are dialyzable 1
• TMP-SMX: Give supplemental dose (half of daily dose) after each dialysis session 1
• Fluoroquinolones: Reduce dose to 250 mg levofloxacin once daily 4
• Beta-lactams: Ceftriaxone requires no adjustment; ertapenem reduced to 500 mg daily 5

Catheter Management:

• If indwelling catheter present >2 weeks, replace catheter before initiating antibiotics and obtain culture from fresh catheter 3, 2
• Never collect urine from collection bag or extension tubing - always from freshly placed catheter 1
• Consider catheter removal entirely if clinically feasible, as this is the most effective intervention to prevent recurrent CA-UTI 1

Culture-Directed Therapy

• Always adjust therapy based on susceptibility results when available 1, 2
• If symptoms persist or recur within 2 weeks, do not use the same antibiotic - this indicates treatment failure requiring alternative susceptibility-guided therapy 1
• Expect broader bacterial spectrum in dialysis patients, including Klebsiella, Proteus, and resistant organisms 4, 8

Common Pitfalls to Avoid

Critical Errors:

• Never treat asymptomatic bacteriuria in dialysis patients - this is the most common error and promotes resistance without clinical benefit 3
• Do not use nitrofurantoin in dialysis patients - inadequate urinary concentrations make it ineffective 4, 6
• Avoid empiric fluoroquinolones as first-line unless other options contraindicated, due to increasing resistance and serious adverse effects 1, 4

Diagnostic Pitfalls:

• Pyuria alone does not indicate infection - it is commonly present without infection in dialysis patients 6
• Cloudy or smelly urine alone should not trigger treatment - these are not reliable indicators of symptomatic infection 3
• Bacteriuria >10^5 CFU/mL without symptoms is ASB, not UTI, and should not be treated 3

Antimicrobial Stewardship

• Reserve carbapenems and broad-spectrum agents for culture-proven resistant organisms only 4
• Avoid prophylactic antibiotics in dialysis patients with catheters - this does not reduce symptomatic UTI and significantly increases resistance 2
• Consider local antibiogram data when selecting empiric therapy, as resistance patterns vary by institution 2, 4