Treatment of Pseudomonas aeruginosa Urinary Tract Infection
For Pseudomonas aeruginosa UTI, obtain urine culture and susceptibility testing before initiating treatment, then use fluoroquinolones (ciprofloxacin 500 mg twice daily or levofloxacin 500 mg once daily) as first-line therapy when susceptibility is confirmed, or aminoglycosides (tobramycin or gentamicin) for complicated infections requiring parenteral therapy. 1, 2, 3
Initial Diagnostic Approach
Obtain urine culture and susceptibility testing before starting antibiotics to guide treatment decisions, as Pseudomonas species demonstrate variable resistance patterns and this testing is essential for tailoring therapy 1, 4
Recognize that Pseudomonas aeruginosa commonly causes complicated UTIs in patients with structural/functional urinary tract abnormalities, indwelling catheters, or recent antimicrobial exposure 1, 5
Do not treat asymptomatic bacteriuria even when Pseudomonas is isolated, unless the patient is pregnant or undergoing invasive urinary procedures 4
First-Line Antibiotic Selection
For Uncomplicated or Mild Complicated UTI (Oral Therapy)
Use fluoroquinolones as first-line agents when susceptibility is confirmed: ciprofloxacin 500 mg twice daily or levofloxacin 500 mg once daily for 7-10 days 1, 2, 6
Levofloxacin demonstrates superior microbiologic eradication rates (79%) compared to ciprofloxacin (53%) in catheterized patients 1
Avoid fluoroquinolones if the patient used them within the past 6 months or if local resistance rates are high, as Pseudomonas can develop resistance rapidly during treatment 1, 2
For less susceptible strains, ciprofloxacin can be increased to 750 mg twice daily or levofloxacin to 500 mg twice daily 6
For Complicated UTI with Systemic Symptoms (Parenteral Therapy)
Use aminoglycosides as first-line parenteral therapy: tobramycin 5-7.5 mg/kg/day divided every 8 hours or gentamicin 7.5 mg/kg/day divided every 8 hours 3, 4
Alternative parenteral options include third-generation cephalosporins (ceftazidime 100-150 mg/kg/day divided every 8 hours) or piperacillin 300 mg/kg/day divided every 6-8 hours 4, 3
Consider combination therapy with amoxicillin plus an aminoglycoside, or a second-generation cephalosporin plus an aminoglycoside for severe infections 1
Special Considerations for Resistant Strains
For carbapenem-resistant or difficult-to-treat resistant Pseudomonas aeruginosa, use colistin monotherapy or combination therapy, ceftolozane/tazobactam, ceftazidime/avibactam, or imipenem/cilastatin/relebactam 1
Monitor for emergence of resistance during therapy, particularly with fluoroquinolones, as resistance can develop in up to 30% of Pseudomonas aeruginosa infections during treatment 2, 7
Treatment Duration and Monitoring
Treat for 7-10 days maximum for most UTIs, using the shortest effective duration to minimize resistance development and adverse effects 4, 1
Replace indwelling catheters that have been in place ≥2 weeks at the onset of catheter-associated UTI to hasten symptom resolution 1
Obtain urine culture specimens from freshly placed catheters prior to initiating antimicrobial therapy 1
Perform culture and susceptibility testing periodically during therapy to monitor for continued susceptibility and emergence of resistance 1, 2
Critical Pitfalls to Avoid
Do not use nitrofurantoin, trimethoprim-sulfamethoxazole, or fosfomycin for Pseudomonas aeruginosa UTI, as these standard first-line agents for typical UTIs lack adequate activity against Pseudomonas 4
Avoid classifying patients with Pseudomonas UTI as "complicated" reflexively, as this leads to unnecessary broad-spectrum antibiotic use with prolonged durations 1
Do not prescribe additional antibiotics for persistent symptoms without repeating urine culture to assess for ongoing bacteriuria versus alternative diagnoses 1
Monitor closely for aminoglycoside toxicity (nephrotoxicity and ototoxicity) with serum concentration monitoring, particularly in patients with renal impairment, prolonged therapy, or concurrent use of other nephrotoxic drugs 3
Patients with indwelling catheters have significantly higher rates of febrile infection (66.7% vs 40.5%), requiring more aggressive management and catheter optimization 5