Treatment Recommendation for Ciprofloxacin-Resistant, Nitrofurantoin-Susceptible UTI
Nitrofurantoin (Macrobid) 100 mg orally twice daily for 5-7 days is the recommended treatment for this uncomplicated urinary tract infection caused by E. coli resistant to ciprofloxacin but susceptible to nitrofurantoin. 1, 2
Primary Treatment Choice
- Nitrofurantoin monohydrate/macrocrystals 100 mg orally twice daily achieves clinical cure rates of 88-95% and bacteriologic cure rates of 86-92% for uncomplicated UTIs 1
- The standard duration is 5-7 days for uncomplicated cystitis in women, with 5-day regimens showing equivalent efficacy to 7-day courses 1
- Nitrofurantoin maintains excellent activity against E. coli with resistance rates of only 2.3%, even among isolates resistant to other agents 3
Why Nitrofurantoin Over Other Options
- Among TMP-SMX-resistant E. coli isolates, only 1.9% show resistance to nitrofurantoin, compared to 9.5% resistant to ciprofloxacin 4
- Nitrofurantoin demonstrates 95.6% susceptibility rates against E. coli uropathogens, making it superior to fluoroquinolones (75.6% susceptibility) and TMP-SMX (71% susceptibility) 3
- Current IDSA guidelines recommend reserving fluoroquinolones as alternative agents only when other antimicrobials cannot be used, due to resistance promotion and collateral damage to normal flora 2
Clinical Efficacy Evidence
- Head-to-head trials show nitrofurantoin achieves early clinical cure rates of 90-95%, comparable to ciprofloxacin (95%) and TMP-SMX (95%) 1
- Late clinical cure rates (4-6 weeks post-treatment) remain high at 84-93% 1
- A 3-day regimen of nitrofurantoin macrocrystals 100 mg four times daily achieved 88% clinical cure and 74% bacteriologic cure, significantly superior to placebo 1
Critical Prescribing Caveats
- Do not use nitrofurantoin for pyelonephritis or complicated UTI - it achieves inadequate tissue concentrations outside the urinary tract 1
- Nitrofurantoin is contraindicated in patients with creatinine clearance <30 mL/min due to inadequate urinary drug concentrations 1
- The twice-daily monohydrate/macrocrystal formulation (Macrobid) is preferred over the four-times-daily macrocrystal formulation for improved adherence 1
Alternative Considerations if Nitrofurantoin Cannot Be Used
- Fosfomycin 3 g single oral dose achieves 90-94% clinical cure rates and represents a reasonable alternative 1
- For VRE-related uncomplicated UTI (less common scenario), fosfomycin or high-dose ampicillin (18-30 g IV daily) are options, though this is not the typical E. coli scenario 1
- Avoid empiric use of any fluoroquinolone given documented resistance and guideline recommendations to reserve these agents 2, 5