What is the appropriate treatment for a 68-year-old male with Urinary Tract Infection (UTI) symptoms and a urine culture positive for Aerococcus urinae?

Treatment of UTI with Aerococcus urinae in a 68-year-old Male

For a 68-year-old male with UTI symptoms and urine culture positive for Aerococcus urinae, the recommended treatment is a 14-day course of penicillin, amoxicillin, or nitrofurantoin based on susceptibility testing. 1

Diagnostic Considerations

• Aerococcus urinae is an emerging uropathogen, particularly in older adults with multimorbidity and urologic conditions
• Proper diagnosis requires:
  • Positive urine culture with ≥50,000 CFU/mL of Aerococcus urinae
  • Presence of urinary symptoms 2
• UTI in males is considered a complicated UTI according to European Association of Urology (EAU) guidelines 3

Treatment Algorithm

First-line Treatment Options:

1. Penicillin or Amoxicillin

   • First choice based on high susceptibility rates (100% for ampicillin) 4
   • Duration: 14 days (recommended for males with UTI as prostatitis cannot be excluded) 3

2. Nitrofurantoin

   • Alternative first-line option with good clinical efficacy
   • Clinical and microbiological success rates of 71% and 76% respectively for A. urinae UTI 5
   • Duration: 14 days for complicated UTI in males

Second-line Options (based on susceptibility):

• Pivmecillinam - Effective for A. urinae cystitis 5
• Ceftriaxone - High susceptibility reported (100%) 6, 4
• Vancomycin - Reserved for severe infections or when other options aren't suitable 6, 4

Avoid:

• Ciprofloxacin - Resistance rates of approximately 10.9% have been reported 4
• Nitroxoline - While active against A. urinae, clinical data is limited 4

Special Considerations

• Obtain antibiotic susceptibility testing before initiating therapy if possible, as resistance patterns can vary 1, 6
• Evaluate for underlying urological abnormalities as A. urinae infections are common in men with urological conditions 7
• Monitor for clinical response within 72 hours of initiating therapy 2
• Consider urology consultation if:
  • No improvement after 72 hours of appropriate therapy
  • Recurrent infections
  • Suspected anatomical abnormalities 2

Potential Complications

• A. urinae can cause invasive infections including bacteremia and infective endocarditis, particularly in older men 7
• Untreated A. urinae infections can progress to urosepsis 6
• Monitor for signs of systemic infection that may require hospital admission:
  • Fever >38°C
  • Hemodynamic instability
  • Signs of sepsis 2

Follow-up

• Obtain a follow-up urine culture after completion of therapy to confirm microbiological cure
• Assess for complete resolution of symptoms
• Consider urological evaluation if this is a recurrent infection or if there are concerns about underlying structural abnormalities