What are the recommended antibiotics for Aerococcus urinae infections?

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Last updated: April 26, 2025 • View editorial policy

From the Research

Nitrofurantoin is the recommended first-line antibiotic treatment for Aerococcus urinae infections, achieving clinical and microbiological success in 71/76% of cases, as demonstrated in a prospective observational study 1.

Key Points

  • Aerococcus urinae is a gram-positive coccus that typically causes urinary tract infections but can lead to more serious conditions like bacteremia, endocarditis, or sepsis, particularly in elderly patients with underlying urological conditions.
  • The most recent and highest quality study, published in 2023, found that Aerococcus urinae isolates are highly susceptible to nitrofurantoin, with low MICs 2.
  • Other antibiotics, such as penicillin G, ampicillin, and vancomycin, may also be effective, but nitrofurantoin is the preferred choice due to its high success rate and low resistance rates.
  • Antimicrobial susceptibility testing is recommended when available to guide treatment decisions.
  • Treatment should be adjusted based on clinical response, with longer courses (4-6 weeks) necessary for endocarditis or other deep-seated infections.

Considerations

  • Patients with penicillin allergies may require alternative treatments, such as vancomycin or nitrofurantoin.
  • Gentamicin may be added for synergistic effect in severe infections like endocarditis or bacteremia.
  • The choice of antibiotic should be guided by local resistance patterns and patient-specific factors, such as underlying medical conditions and potential drug interactions.

Evidence

  • A prospective observational study published in 2018 found that nitrofurantoin was effective in treating Aerococcus urinae urinary tract infections, with a clinical and microbiological success rate of 71/76% 1.
  • A study published in 2023 found that Aerococcus urinae isolates were highly susceptible to nitrofurantoin, with low MICs 2.
  • Other studies have reported variable resistance rates to other antibiotics, highlighting the importance of antimicrobial susceptibility testing to guide treatment decisions 3, 4, 5.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.