What antibiotics are used to treat Aerococcus infections?

Antibiotic Treatment for Aerococcus Infections

Penicillin is the first-line antibiotic treatment for Aerococcus infections, with combination therapy including an aminoglycoside recommended for serious infections such as endocarditis or bacteremia. For less severe infections like uncomplicated urinary tract infections, ampicillin or nitrofurantoin are appropriate options.

First-Line Treatment Options

Invasive Aerococcus Infections

• Penicillin or ampicillin is the cornerstone of treatment for invasive Aerococcus infections 1, 2
• For serious infections (endocarditis, bacteremia):
  • Combine penicillin with an aminoglycoside for synergistic effect 2, 3
  • This combination is particularly important for Aerococcus urinae endocarditis

Urinary Tract Infections

• Ampicillin is considered a safe treatment option for complicated UTIs 3
• Nitrofurantoin is effective for uncomplicated UTIs 3, 4
• Recent studies show 100% susceptibility of Aerococcus species to nitrofurantoin 4

Alternative Treatment Options

When penicillins cannot be used, the following alternatives are appropriate:

• Vancomycin: 100% susceptibility reported in recent studies 4
• Carbapenems (e.g., meropenem): Highly effective against Aerococcus species 3, 4

Antibiotics to Avoid

• Fluoroquinolones: Approximately 10.9% of Aerococcus isolates show resistance to ciprofloxacin 4
• Trimethoprim-sulfamethoxazole: A. urinae is resistant to sulfamethoxazole, and there are methodological problems in determining trimethoprim sensitivity 3

Species-Specific Considerations

Aerococcus urinae

• Highly susceptible to penicillins, carbapenems, vancomycin, and nitrofurantoin 4
• Nitroxoline shows promising activity (97.6% susceptibility) and could be an alternative for UTIs, though clinical studies are needed 4

Aerococcus sanguinicola

• Similar susceptibility pattern to A. urinae for most antibiotics
• Not susceptible to nitroxoline (should be considered intrinsically resistant) 4

Treatment Duration and Monitoring

• For uncomplicated UTIs: Standard short-course therapy (typically 3-5 days)
• For invasive infections: Extended therapy (2-4 weeks for bacteremia; 4-6 weeks for endocarditis)
• Close monitoring of clinical status and laboratory results is essential, especially for serious infections 2

Clinical Pearls

• Aerococci are gram-positive cocci often misidentified as streptococci or staphylococci 1
• Aerococcus infections are more common in elderly patients with urinary tract abnormalities or indwelling catheters 5
• Prompt and culture-specific treatment is critical to avoid clinical progression of the infection 5
• Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has improved accurate identification of Aerococcus species 1

The treatment of Aerococcus infections should be guided by antimicrobial susceptibility testing whenever possible, as patterns of resistance may vary regionally.