From the Guidelines
Yes, Macrobid (nitrofurantoin) would be effective against this Escherichia coli infection. The susceptibility report shows that the E. coli is susceptible to nitrofurantoin, which is the active ingredient in Macrobid, with a clinical cure rate of 88% - 93% and a bacterial cure rate of 81% - 92% as demonstrated in studies 1. This means the antibiotic should successfully treat the infection. Nitrofurantoin is particularly effective for urinary tract infections caused by E. coli because it concentrates in the urine.
Key Points to Consider
- The typical dosage for Macrobid is 100 mg twice daily for 5-7 days for uncomplicated UTIs, as shown in studies comparing nitrofurantoin to other antibiotics such as trimethoprim-sulfamethoxazole and ciprofloxacin 1.
- It's essential to complete the full course of antibiotics even if symptoms improve before finishing.
- Nitrofurantoin should be taken with food to increase absorption and reduce stomach upset.
- The susceptibility report also shows this E. coli strain is resistant to trimethoprim/sulfamethoxazole and has intermediate susceptibility to ciprofloxacin and levofloxacin, making nitrofurantoin a good choice for treatment, as supported by the high clinical and microbiological cure rates in studies 1.
Important Considerations
- The studies demonstrate that nitrofurantoin monohydrate/macrocrystals (100 mg twice daily for 7 days) has similar clinical cure rates to ciprofloxacin (100 mg twice daily for 3 days) and trimethoprim-sulfamethoxazole (160/800 mg twice daily for 7 days) 1.
- A meta-analysis of studies comparing early clinical cure rates with nitrofurantoin and trimethoprim-sulfamethoxazole shows no significant difference in efficacy 1.
From the Research
Effectiveness of Macrobid (Nitrofurantoin)
- The provided susceptibility test results show that the Escherichia coli strain is susceptible to Nitrofurantoin, with a susceptible MIC value [ 2 ].
- Studies have demonstrated the effectiveness of Nitrofurantoin in treating urinary tract infections (UTIs), with high susceptibility rates among common UTI pathogens, including Escherichia coli [ 2 , 3 ].
- A systematic review and meta-analysis found that Nitrofurantoin is effective in preventing UTIs, with a risk ratio of 0.38 in favor of Nitrofurantoin compared to no prophylaxis [ 4 ].
Comparison with Other Antibiotics
- The susceptibility test results show that the Escherichia coli strain is resistant to Trimethoprim/Sulfamethoxazole, which is consistent with the high resistance rates reported in some studies [ 2 , 5 ].
- In contrast, Nitrofurantoin has been shown to have a favorable resistance profile, making it a suitable option for treating UTIs in certain regions [ 5 ].
- Other antibiotics, such as amoxicillin/clavulanate and cefdinir, may also be effective alternatives, depending on local resistance patterns [ 5 ].
Treatment Duration and Efficacy
- A retrospective cohort study found that 5-day and 7-day treatment durations with Nitrofurantoin had similar efficacy in treating UTIs in women with diabetes [ 6 ].
- The study suggested that a 5-day treatment duration may be sufficient to reduce cumulative Nitrofurantoin exposure in patients with diabetes [ 6 ].