Treatment of Pan-Sensitive E. coli or Klebsiella UTI with Augmentin
Augmentin (amoxicillin-clavulanate) is an appropriate and effective treatment option for urinary tract infections caused by pan-sensitive E. coli or Klebsiella species, but it should be reserved as a second-line agent when first-line options are contraindicated or unavailable. 1
FDA-Approved Indication
Augmentin is FDA-approved specifically for urinary tract infections caused by beta-lactamase-producing isolates of E. coli, Klebsiella species, and Enterobacter species 1. However, the FDA label explicitly states that when susceptibility testing shows the organism is susceptible to amoxicillin alone (indicating no beta-lactamase production), Augmentin should not be used 1.
Clinical Efficacy Evidence
For pan-sensitive organisms, Augmentin demonstrates excellent clinical outcomes:
- Historical clinical trials show bacteriological cure rates of 84% at one week post-treatment and 67% at one month for recurrent UTIs 2
- In complicated UTI populations (including spinal injury patients with indwelling catheters), Augmentin achieved 100% bacteriological success at 24 hours and 69% at 8 days post-therapy 3
- The combination is particularly valuable for multiply-resistant bacteria, though your organisms are pan-sensitive 4, 5
Recommended Approach
For uncomplicated cystitis in otherwise healthy women, prioritize first-line agents:
- 5-day course of nitrofurantoin 6, 7
- Single 3-gram dose of fosfomycin 6, 7
- 5-day course of pivmecillinam (where available) 7
Use Augmentin as a second-line option when:
- Patient has contraindications to first-line agents 6
- Penicillin allergy is absent 6
- Local resistance patterns favor beta-lactam use 6
For complicated UTIs with systemic symptoms, consider alternative regimens first:
- Amoxicillin plus an aminoglycoside 6
- Second-generation cephalosporin plus an aminoglycoside 6
- Intravenous third-generation cephalosporin 6
Dosing Regimen
Standard dosing for UTI: 375 mg (250 mg amoxicillin/125 mg clavulanate) orally three times daily for 5-7 days 3, 2. For complicated UTIs or when prostatitis cannot be excluded in men, extend treatment to 7-14 days 6.
Important Caveats
Antimicrobial stewardship considerations:
- Since your organisms are pan-sensitive (including to amoxicillin alone), using the combination unnecessarily adds clavulanate exposure without clinical benefit 1
- Reserve beta-lactam/beta-lactamase inhibitor combinations for organisms that actually produce beta-lactamase to minimize collateral damage and resistance development 6, 7
- Consider using amoxicillin alone if susceptibility confirms no beta-lactamase production 1
Side effects are generally mild:
- Gastrointestinal effects occur in approximately 20% of patients but rarely require discontinuation 2
- No significant hematological, renal, or hepatic toxicity reported in clinical trials 3
Avoid fluoroquinolones empirically if the patient has used them in the last 6 months or comes from a urology department, even though ciprofloxacin resistance is <10% in many regions 6.