From the Research
Nitrofurantoin (Macrobid) can be effective against some ESBL-producing bacteria, particularly for uncomplicated urinary tract infections, as supported by the most recent study 1 from 2020.
Key Points to Consider
- ESBL (Extended-Spectrum Beta-Lactamase) producing organisms are resistant to many antibiotics, but nitrofurantoin works through a different mechanism that often remains effective against these bacteria.
- The typical dosage for Macrobid is 100 mg twice daily for 5-7 days for uncomplicated UTIs.
- However, nitrofurantoin is only appropriate for lower urinary tract infections as it concentrates in the urine but doesn't achieve adequate levels in bloodstream or tissues for systemic infections.
- Before using Macrobid for ESBL infections, susceptibility testing should be performed to confirm the organism's sensitivity, as recommended by studies such as 2 and 3.
- Nitrofurantoin should be avoided in patients with creatinine clearance below 60 ml/min, during late pregnancy, and in those with G6PD deficiency.
- For complicated UTIs, pyelonephritis, or systemic infections caused by ESBL organisms, other antibiotics like carbapenems (meropenem, ertapenem) are typically required instead of Macrobid, as indicated by studies like 1 and 4.
Mechanism and Efficacy
- Nitrofurantoin's efficacy against ESBL-producing bacteria is attributed to its unique mechanism of action, which is different from that of beta-lactam antibiotics, as discussed in 5.
- Studies have shown that nitrofurantoin can be effective against ESBL-producing E. coli and Klebsiella pneumoniae, with susceptibility rates ranging from 93% to 96% for E. coli and 42% to 83% for Klebsiella species, as reported in 2 and 3.
Clinical Considerations
- When considering the use of nitrofurantoin for ESBL infections, it is essential to weigh the benefits against the potential risks and consider alternative treatment options, especially for complicated or severe infections.
- The emergence of multidrug-resistant ESBL-producing Enterobacteriaceae restricts therapeutic options, making the use of nitrofurantoin and other oral antibiotics like pivmecillinam and fosfomycin crucial for the treatment of uncomplicated UTIs, as highlighted in 1 and 2.