What antibiotic will cover Enterococcus (E.) faecalis and Escherichia (E.) coli at the same time in a woman with cystitis?

Antibiotic Selection for E. faecalis and E. coli in Cystitis

Nitrofurantoin is the optimal antibiotic choice for covering both Enterococcus faecalis and Escherichia coli simultaneously in a woman with cystitis, with a recommended dosage of 100 mg twice daily for 5 days. 1, 2

First-Line Options

Nitrofurantoin offers several advantages for treating cystitis caused by these organisms:

• Excellent activity against both E. faecalis and E. coli 1
• Low resistance rates despite years of use 2
• Minimal collateral damage to gut flora 2, 1
• FDA-approved for UTIs caused by E. faecalis 1
• Recommended by IDSA/ESCMID guidelines for uncomplicated cystitis 2

Alternative First-Line Option:

• Fosfomycin 3g single dose - FDA approved for UTIs caused by E. faecalis and effective against E. coli 1, 2

Second-Line Options

If nitrofurantoin or fosfomycin cannot be used:

1. Amoxicillin-clavulanate 500/125 mg orally three times daily for 7 days

   • Effective against E. faecalis and some E. coli strains 1
   • Note: Clinical cure rates are lower than fluoroquinolones (58% vs 77%) 3
   • Consider only when susceptibility is confirmed due to variable E. coli resistance

2. Fluoroquinolones (e.g., ciprofloxacin 250 mg twice daily for 3 days)

   • Highly effective against E. coli 2
   • Active against E. faecalis (per levofloxacin FDA label) 4
   • Should be reserved due to:
     • Risk of serious adverse effects 1
     • Increasing resistance concerns 2, 5
     • Potential for promoting resistance to drugs needed for more serious infections 6

Important Clinical Considerations

Avoid These Common Pitfalls:

1. Using trimethoprim-sulfamethoxazole empirically

   • While recommended for uncomplicated cystitis (3-day course) 2, it has poor activity against E. faecalis
   • Only use if susceptibility testing confirms activity against both organisms

2. Using oral β-lactams as first-line therapy

   • Generally less effective than other available agents 2
   • Amoxicillin alone has high resistance rates among E. coli 1

3. Ignoring local antibiogram data

   • Local resistance patterns should guide therapy when available 1
   • Geographic variability in susceptibility is significant 2

Special Considerations:

• Renal function: Nitrofurantoin is contraindicated if CrCl <30 mL/min 1
• Duration: 5 days for nitrofurantoin is recommended by IDSA/ESCMID guidelines 2
• Follow-up: If symptoms persist beyond 48-72 hours, consider urine culture and susceptibility testing to guide alternative therapy 1

By selecting nitrofurantoin as first-line therapy, you maximize the chances of effectively treating both E. faecalis and E. coli while minimizing the risk of promoting antimicrobial resistance.