Does nitrofurantoin cover Group B Streptococcus (GBS) urinary tract infections (UTIs)?

Nitrofurantoin Efficacy Against Group B Streptococcus UTIs

Nitrofurantoin is effective for treating uncomplicated urinary tract infections caused by Group B Streptococcus (GBS) and is recommended as a first-line treatment option for lower UTIs. 1

Efficacy Against GBS

• Nitrofurantoin has broad-spectrum bactericidal activity against both Gram-positive and Gram-negative pathogens, including Group B Streptococcus 1
• It achieves high urinary concentrations that are effective against common uropathogens, making it suitable for treating lower UTIs caused by susceptible organisms including GBS 1
• Research from South Africa demonstrated that Group B Streptococcus is one of the most common Gram-positive pathogens causing UTIs, and nitrofurantoin maintained good susceptibility against uropathogens 2
• Nitrofurantoin is particularly effective against Gram-positive organisms similar to GBS, as evidenced by its recommendation for treating UTIs due to vancomycin-resistant enterococci (VRE) 1

Treatment Recommendations for UTIs

• The WHO Essential Medicines Expert Committee recommends nitrofurantoin as a second-choice option for lower urinary tract infections 3
• Nitrofurantoin maintains high susceptibility rates against common uropathogens, with resistance rates as low as 2.3% compared to fluoroquinolones (24%) and co-trimoxazole (29%) 4
• For uncomplicated lower UTIs, nitrofurantoin is increasingly being repositioned as first-line therapy due to its continued effectiveness and low resistance rates 5
• Nitrofurantoin has demonstrated superior efficacy compared to placebo in achieving both symptomatic relief and bacteriological cure in women with UTIs 6

Dosing Recommendations

• For treating uncomplicated UTIs, including those caused by GBS, the recommended dosing options are:
  • Nitrofurantoin macrocrystals: 50-100 mg four times daily for 5 days 1
  • Nitrofurantoin monohydrate/macrocrystals (Macrobid): 100 mg twice daily for 5 days 1

Clinical Considerations and Limitations

• Nitrofurantoin should only be used for lower UTIs (cystitis) and not for upper UTIs (pyelonephritis) or systemic infections, as it does not achieve adequate tissue concentrations outside the urinary tract 3, 1
• The drug has been in clinical use for over 35 years with a continuing safety record and lack of associated R-factor resistance compared to newer antimicrobials 7
• Caution should be exercised when prescribing nitrofurantoin to elderly patients for chronic UTIs due to potential long-term side effects 5
• If nitrofurantoin cannot be used or resistance is suspected, alternative options include amoxicillin-clavulanic acid or trimethoprim-sulfamethoxazole for lower UTIs 3, 1