Do you treat a urinary analysis showing 50-100 thousand colonies of Staphylococcus hominis with antibiotics?

Management of Staphylococcus hominis in Urinalysis with 50-100 Thousand Colony Count

Do not treat asymptomatic bacteriuria with Staphylococcus hominis at 50-100 thousand colony count in the absence of urinary symptoms. 1, 2

Diagnostic Considerations

• Asymptomatic bacteriuria is defined as >10^5 CFU/mL in two consecutive samples in women or a single sample in men, without urinary symptoms 2
• The presence of bacteria in urine without symptoms does not constitute a urinary tract infection requiring treatment 1
• Staphylococcus species other than Staphylococcus saprophyticus are rarely true uropathogens and often represent contamination, especially at lower colony counts 3, 4
• For a true UTI diagnosis, both urinalysis results suggesting infection (pyuria, positive leukocyte esterase, nitrites) AND the presence of symptoms are required 3, 5

Treatment Decision Algorithm

1. Assess for symptoms:

   • If patient has dysuria, frequency, urgency, or suprapubic pain → consider treatment 1
   • If completely asymptomatic → do not treat 1

2. Evaluate patient risk factors:

   • Pregnancy → treat asymptomatic bacteriuria 2
   • Planned urological procedure with mucosal bleeding → treat 2
   • Neurogenic bladder → do not treat asymptomatic bacteriuria 1
   • Otherwise healthy individual → do not treat asymptomatic bacteriuria 1, 3

3. Consider organism and colony count:

   • Staphylococcus hominis is not a common uropathogen and may represent contamination 4, 6
   • Colony count of 50-100 thousand is at the threshold for significance but requires symptoms to warrant treatment 2, 3

Rationale for Non-Treatment

• Treating asymptomatic bacteriuria leads to unnecessary antibiotic use and contributes to antimicrobial resistance 1, 3
• Treatment of asymptomatic bacteriuria is associated with early recurrence with more resistant bacterial strains 1
• Diagnostic stewardship is essential to prevent unnecessary treatment of asymptomatic bacteriuria 1
• The European Association of Urology strongly recommends against treating asymptomatic bacteriuria in individuals without risk factors 3

Special Circumstances for Treatment

• Treat asymptomatic bacteriuria only in:
  • Pregnant women (to prevent complications) 2
  • Prior to urological procedures with anticipated mucosal bleeding 2
  • Before traumatic urinary tract interventions (e.g., transurethral resection of the prostate) 1

Clinical Pitfalls to Avoid

• Do not perform surveillance/screening urine cultures in asymptomatic patients 1
• Do not treat based solely on colony count without considering symptoms 1, 3
• Do not assume all bacteria in urine represent infection; bacterial quantity does not correlate with antimicrobial resistance 7
• Remember that pyuria is commonly found in the absence of infection, particularly in older adults 5

By following these evidence-based guidelines, you can practice appropriate antibiotic stewardship while ensuring optimal patient outcomes in terms of morbidity, mortality, and quality of life.