Is oral Augmentin (amoxicillin-clavulanate) 625mg three times a day effective for treating a febrile urinary tract infection (UTI) caused by E. coli that is susceptible to Augmentin (amoxicillin-clavulanate) but not to amoxicillin?

Treatment of E. coli Febrile UTI with Augmentin 625mg TID

Oral Augmentin (amoxicillin-clavulanate) 625mg three times daily is an effective treatment option for febrile UTI caused by E. coli that is susceptible to Augmentin but resistant to amoxicillin alone. 1, 2

Rationale for Augmentin in E. coli UTIs

• Amoxicillin-clavulanate is specifically recommended as an appropriate oral treatment option for UTIs, including febrile UTIs, in clinical practice guidelines 1
• The clavulanic acid component inhibits beta-lactamases produced by resistant E. coli strains, restoring the effectiveness of amoxicillin against organisms that would otherwise be resistant to amoxicillin alone 3
• For E. coli strains that are resistant to amoxicillin but susceptible to amoxicillin-clavulanate, the combination provides effective coverage while allowing for oral outpatient treatment 4

Dosing and Duration Considerations

• The recommended dosage of amoxicillin-clavulanate for UTIs is 20-40 mg/kg per day in 3 doses (based on the amoxicillin component), which aligns with the 625mg TID dosing for adults 1
• Treatment duration for febrile UTIs should be 7-14 days, with 7 days being sufficient when the patient becomes afebrile and clinically improves 1
• A shorter course (7 days) may be considered when the patient has been afebrile for at least 48 hours and is hemodynamically stable 1

Efficacy Against Resistant Strains

• Studies have shown that amoxicillin-clavulanate can be effective against some ESBL-producing E. coli strains when the organism tests susceptible to the combination 4, 5
• In a study of ESBL-producing E. coli UTIs, amoxicillin-clavulanate in combination with a single dose of amikacin achieved clinical improvement in 78.7% of patients 5
• For complicated UTIs with resistant organisms, amoxicillin-clavulanate is included among the recommended beta-lactam/beta-lactamase inhibitor combinations that can be used when the organism is susceptible 1

Alternative Options to Consider

• If the patient fails to respond to Augmentin or has severe infection, consider:
  • Parenteral therapy with ceftriaxone, cefotaxime, or an aminoglycoside 1
  • Fluoroquinolones (if local resistance rates are <10%) 1
  • Carbapenems for highly resistant strains 3

Monitoring and Follow-up

• Clinical response should be assessed within 48-72 hours of initiating treatment 1
• Patients should be monitored for resolution of fever and improvement of urinary symptoms 1
• Urine culture and susceptibility testing are essential for guiding definitive therapy, especially in complicated cases or treatment failures 2

Common Pitfalls

• Failure to obtain urine cultures before initiating antibiotics may lead to inappropriate therapy if the organism has unexpected resistance patterns 1
• Using amoxicillin alone would be ineffective if the E. coli strain produces beta-lactamases, as indicated by the susceptibility pattern in this case 3
• Nitrofurantoin should not be used for febrile UTIs as it does not achieve adequate tissue concentrations to treat upper tract infections 1