What is the next best step for an 81-year-old woman with a history of E coli Urinary Tract Infection (UTI), previously treated with Macrobid (nitrofurantoin), who now has a recurrent E coli UTI?

Management of Recurrent E. coli UTI in an 81-year-old Woman

For an 81-year-old woman with a history of E. coli UTI previously treated with nitrofurantoin (Macrobid) who now has recurrent E. coli on urine culture, the next best step is to treat with a 5-day course of nitrofurantoin (100 mg twice daily) as it remains an effective first-line agent for recurrent uncomplicated UTIs with low resistance rates. 1

Diagnostic Approach

• Confirm the diagnosis through urine culture (which has already been done in this case) 1
• Determine if this is a true recurrence (same organism after complete clinical resolution) versus a relapse (within 2 weeks of treatment) 1
• Assess for symptoms - treatment should be guided by presence of symptoms rather than culture results alone 1

Treatment Options for Recurrent E. coli UTI

First-line Treatment Options:

• Nitrofurantoin (preferred option):

  • Dosage: 100 mg twice daily for 5 days 1
  • Advantages: Low resistance rates for E. coli (approximately 2-5%) compared to other antibiotics 2, 3
  • E. coli resistance to nitrofurantoin decays quickly (only 20.2% at 3 months and 5.7% at 9 months) 1

• Fosfomycin trometamol:

  • Dosage: 3 g single dose 1
  • Recommended only for uncomplicated cystitis 1

• Trimethoprim-sulfamethoxazole:

  • Dosage: 160/800 mg twice daily for 3 days 1
  • Caution: Increasing resistance rates (14.6-60% in European countries) may limit efficacy 2

Special Considerations for Elderly Women

• Postmenopausal women are at increased risk for recurrent UTI due to:

  • Urinary incontinence 1
  • Cystocele 1
  • High postvoid residuals 1

• Vaginal estrogen therapy should be strongly considered in this 81-year-old woman to prevent future UTIs 1

  • Vaginal estrogen has been shown to significantly reduce recurrent UTI risk in postmenopausal women 1

Prevention Strategies After Treatment

After treating the current infection, consider these preventive measures:

• Vaginal estrogen (as mentioned above) 1
• Methenamine hippurate is strongly recommended to reduce recurrent UTI episodes in women without urinary tract abnormalities 1
• Increased fluid intake may help reduce the risk of recurrent UTI 1
• Immunoactive prophylaxis can be considered to reduce recurrent UTI in elderly patients 1
• Continuous or postcoital antimicrobial prophylaxis if non-antimicrobial interventions fail 1
  • Low-dose nitrofurantoin (50-100 mg) is preferred for prophylaxis 1

When to Consider Further Evaluation

• If symptoms persist despite appropriate antibiotic therapy 1
• If recurrences happen rapidly (within 2 weeks) after treatment 1
• If there are signs of complicated UTI (pyelonephritis, structural abnormalities) 1

Pitfalls to Avoid

• Avoid fluoroquinolones (e.g., ciprofloxacin) for uncomplicated UTIs due to:

  • Increasing resistance rates 2
  • FDA warning about serious side effects 1
  • Risk of promoting antimicrobial resistance 1

• Avoid treating asymptomatic bacteriuria in elderly women as this:

  • Increases risk of antimicrobial resistance 1
  • May increase the number of symptomatic UTI episodes 1
  • Does not improve clinical outcomes 1

• Avoid classifying recurrent UTIs as "complicated" simply due to recurrence, as this often leads to unnecessary use of broad-spectrum antibiotics 1

By following these evidence-based recommendations, the patient can receive appropriate treatment for her current infection while implementing strategies to prevent future recurrences.