What is the recommended treatment for a urinary tract infection (UTI) in an Intensive Care Unit (ICU) setting?

UTI Treatment in the ICU

For critically ill ICU patients with urinary tract infections, initiate empirical broad-spectrum intravenous antibiotic therapy covering Enterobacteriaceae and Enterococci immediately, with treatment selection based on whether the infection is healthcare-associated versus community-acquired and local resistance patterns. 1

Initial Empirical Therapy Approach

For Healthcare-Associated/Complicated UTI in ICU Patients

Broad-spectrum coverage is recommended as first-line empirical therapy when patients present with sepsis or septic shock. 1 The choice depends on suspected resistance patterns:

Standard Empirical Options (No MDR Risk):

• Piperacillin-tazobactam 3.375-4.5 g IV q6h 1
• Ceftazidime 2 g IV q8h 1
• Cefepime 1-2 g IV q8-12h 1
• Ciprofloxacin 400 mg IV q8h 1
• Levofloxacin 750 mg IV daily 1

For Suspected Carbapenem-Resistant Enterobacterales (CRE):

• Ceftazidime-avibactam 2.5 g IV q8h (preferred first-line) 1
• Meropenem-vaborbactam 4 g IV q8h 1
• Imipenem-cilastatin-relebactam 1.25 g IV q6h 1
• Aminoglycosides: Gentamicin 5-7 mg/kg/day IV once daily OR Amikacin 15 mg/kg/day IV once daily 1

For Carbapenem-Resistant Pseudomonas aeruginosa (CRPA):

• Ceftolozane-tazobactam 1.5-3 g IV q8h 1
• Ceftazidime-avibactam 2.5 g IV q8h 1
• Colistin: 5 mg CBA/kg IV loading dose, then 2.5 mg CBA × (1.5 × CrCl + 30) IV q12h (monotherapy or combination) 1

Critical Dosing Considerations

Adjust all antibiotic doses based on patient weight, renal clearance, and liver function. 1 This is particularly crucial in ICU patients who frequently have organ dysfunction affecting drug clearance. 1

For aminoglycosides, limit duration to ≤7 days to minimize nephrotoxicity risk. 1 Aminoglycoside monotherapy is only appropriate for urinary tract infections, not for systemic infections or bacteremia. 1

Source Control and Diagnostic Workup

Obtain blood cultures and urine cultures before initiating antibiotics whenever possible, but do not delay treatment. 1 Intraperitoneal fluid cultures should also be obtained if concurrent intra-abdominal pathology is suspected. 1

Remove or replace urinary catheters when feasible, as this constitutes essential source control. 1 If catheter removal is not possible and the patient develops symptomatic UTI, empiric treatment should be initiated until culture results guide definitive therapy. 1

Treatment Duration

For complicated UTI in ICU patients with adequate source control, use short-course therapy of 5-7 days. 1 A French multicenter trial demonstrated that 8-day antibiotic therapy was non-inferior to 15-day therapy in critically ill ICU patients with postoperative intra-abdominal infections after adequate source control, with reduced antibiotic exposure and no additional clinical benefit from longer treatment. 1

Extend duration to 7-14 days for bloodstream infections secondary to UTI. 1 Treatment duration should be individualized based on infection site, adequacy of source control, underlying comorbidities, and initial response to therapy. 1

De-escalation Strategy

Implement antibiotic de-escalation as soon as culture and susceptibility results are available. 1 This involves narrowing from broad-spectrum to targeted therapy based on identified pathogens and their susceptibilities. 1

Procalcitonin-guided therapy can help determine appropriate duration of antibiotic treatment. 1 A meta-analysis of 1,075 patients showed procalcitonin-guided therapy significantly shortened antibiotic duration compared to standard care without compromising outcomes. 1

Step down to oral therapy once patients are clinically stable, afebrile for 24-48 hours, and able to tolerate oral intake. 1 Oral options include fluoroquinolones, trimethoprim-sulfamethoxazole, or cephalosporins based on susceptibility results. 1

Special Considerations

Antifungal Therapy

Empirical antifungal therapy is NOT recommended for UTI in ICU patients. 1 Only consider antifungals if Candida is isolated from cultures and the patient has specific risk factors such as biliopancreatic surgery, ICU stay in previous 90 days, or 30-day reintervention. 1

Multidrug-Resistant Organisms

For infections with metallo-β-lactamase-producing CRE resistant to ceftazidime-avibactam and meropenem-vaborbactam, use cefiderocol. 1 Plazomicin 15 mg/kg IV q12h is an alternative aminoglycoside option for CRE-UTI with activity against KPC-producing strains. 1

Avoid tigecycline for bloodstream infections and pneumonia; if necessary for pneumonia, use high-dose tigecycline (100 mg loading, then 50 mg IV q12h). 1 Tigecycline monotherapy is not recommended for pneumonia. 1

Common Pitfalls

Do not use fluoroquinolones empirically if local resistance rates exceed 10%. 1 High resistance rates in many communities preclude their use as first-line empiric therapy. 2, 3

Avoid nitrofurantoin and fosfomycin for febrile UTI or pyelonephritis in ICU patients. 1 These agents achieve therapeutic concentrations only in urine, not in bloodstream, making them inappropriate for systemic infections. 1

Reserve novel broad-spectrum agents (ceftazidime-avibactam, meropenem-vaborbactam, ceftolozane-tazobactam) for documented MDR organisms. 1 Antimicrobial stewardship principles dictate avoiding these agents for susceptible organisms to prevent resistance development. 1