Treatment of Aerococcus sanguinicola Urinary Tract Infection
For Aerococcus sanguinicola UTI, treat symptomatic infections with antibiotics guided by susceptibility testing, with penicillin, cephalosporins (ceftriaxone), or vancomycin as appropriate first-line options, while nitrofurantoin shows lower efficacy compared to A. urinae infections. 1, 2, 3
When to Treat vs. Observe
- Do not treat asymptomatic bacteriuria with Aerococcus sanguinicola except in pregnant women or before urological procedures breaching the mucosa 4, 5
- Treat symptomatic UTI presenting with dysuria, frequency, urgency, hematuria, or new incontinence 5
- Recognize that untreated A. sanguinicola infections can progress to urosepsis, particularly in elderly patients with urinary tract abnormalities 2, 6
Diagnostic Approach
- Obtain urine culture before initiating treatment to confirm diagnosis and guide antibiotic selection, as A. sanguinicola is easily misidentified as streptococci or staphylococci without MALDI-TOF mass spectrometry 5, 6
- Request antimicrobial susceptibility testing, as treatment recommendations are primarily based on in vitro data and limited clinical experience 1
Antibiotic Selection
First-Line Options for Cystitis
- Nitrofurantoin achieves clinical and microbiological success in only 42%/50% of A. sanguinicola UTI cases respectively, which is notably lower than its 71%/76% success rate for A. urinae 1
- Penicillin or cephalosporins (ceftriaxone) are highly effective, as all tested A. sanguinicola isolates demonstrate susceptibility 2, 3
- Vancomycin is universally effective against A. sanguinicola based on susceptibility data 2, 3
Alternative Agents
- Meropenem, linezolid, and rifampicin show universal susceptibility in vitro 3
- Avoid relying on trimethoprim-sulfamethoxazole and fluoroquinolones as their clinical efficacy against aerococci remains uncertain despite in vitro data 6
Treatment Duration
- Use 7-day courses for uncomplicated cystitis, consistent with general UTI treatment principles 5
- Consider longer courses for complicated infections or in patients with urinary tract abnormalities 6
Special Considerations for Serious Infections
- For pyelonephritis or urosepsis, use intravenous penicillin, ceftriaxone, or vancomycin based on susceptibility results 2, 7
- For bacteremia or endocarditis, use penicillin or ampicillin in combination with an aminoglycoside, with close clinical and laboratory monitoring 7, 6
- Elderly men with urinary tract abnormalities are at highest risk for invasive A. sanguinicola infections 6
Critical Pitfalls to Avoid
- Do not assume nitrofurantoin will be as effective for A. sanguinicola as it is for typical E. coli UTIs or even A. urinae infections, given the 42-50% success rate 1
- Do not treat asymptomatic bacteriuria, as this leads to unnecessary antibiotic exposure and resistance development without clinical benefit 4, 5
- Do not rely on empiric therapy without culture confirmation, as A. sanguinicola is frequently misidentified as other gram-positive cocci, potentially leading to inappropriate treatment 6
- Recognize that A. sanguinicola infections predominantly affect elderly patients (median age 82 years) with comorbidities, requiring careful monitoring for progression to serious infection 2