What is the treatment for a Coagulase-negative (Coag neg) Staphylococcus urinary tract infection (UTI)?

Treatment of Coagulase-negative Staphylococcus UTI

For coagulase-negative staphylococcal UTIs, treatment should follow complicated UTI guidelines with empiric therapy using amoxicillin plus an aminoglycoside, a second-generation cephalosporin plus an aminoglycoside, or an intravenous third-generation cephalosporin, followed by targeted therapy based on susceptibility testing. 1

Classification and Approach

Coagulase-negative staphylococcal (CoNS) UTIs should be considered complicated UTIs, as they:

• Are less common uropathogens than typical gram-negative bacteria
• Often demonstrate antimicrobial resistance
• May be associated with healthcare settings or urological abnormalities

The European Association of Urology (EAU) 2024 guidelines emphasize that complicated UTIs require:

1. Urine culture and susceptibility testing before initiating therapy
2. Initial empiric therapy based on local resistance patterns
3. Tailored therapy once culture results are available
4. Management of any underlying urological abnormalities 1

Empiric Treatment Options

For initial empiric therapy of CoNS UTI with systemic symptoms, the EAU guidelines strongly recommend:

• First-line options:

  • Amoxicillin plus an aminoglycoside
  • A second-generation cephalosporin plus an aminoglycoside
  • An intravenous third-generation cephalosporin 1

• Alternative options (if beta-lactam allergy):

  • Ciprofloxacin (only if local resistance rate <10% AND patient not hospitalized AND no fluoroquinolone use in past 6 months) 1

Species Considerations and Resistance

CoNS UTIs are predominantly caused by:

• Staphylococcus epidermidis (53%)
• Staphylococcus hominis (12%)
• Staphylococcus haemolyticus (10%)
• Staphylococcus saprophyticus (5%) 2

Important resistance patterns to consider:

• S. epidermidis shows higher resistance rates than S. saprophyticus 3
• Common resistance includes penicillin (35%), tetracycline (33%), methicillin (27%), and sulfonamide (24%) 2
• Methicillin resistance is more common in patients with recent hospitalization or antibiotic use 4

Definitive Treatment After Culture Results

Once susceptibility results are available:

• Switch to the narrowest-spectrum effective oral antibiotic
• For methicillin-sensitive strains: first-generation cephalosporins (e.g., cephalexin) are appropriate
• For methicillin-resistant strains: options include:
  • Trimethoprim-sulfamethoxazole
  • Nitrofurantoin
  • Fosfomycin
  • Vancomycin (for severe infections) 1, 5

Treatment Duration

• 7-14 days of therapy is recommended for complicated UTIs 1
• 14 days for men when prostatitis cannot be excluded 1
• Consider shorter duration (7 days) if:
  • Patient is hemodynamically stable
  • Afebrile for at least 48 hours
  • Relative contraindications to longer antibiotic course exist 1

Special Considerations

• Catheter-associated UTI: If CoNS UTI is catheter-associated, remove or replace the catheter before starting antimicrobial therapy 1
• Relapsing infections: Consider longer treatment courses (3 weeks instead of 2 weeks) for relapsing or repeat infections 4
• Underlying abnormalities: Management of any urological abnormality or underlying complicating factor is mandatory for successful treatment 1

Monitoring and Follow-up

• Clinical response should be evident within 48-72 hours of appropriate therapy
• Routine post-treatment cultures are not recommended in asymptomatic patients 1
• Consider alternative diagnoses if symptoms persist despite appropriate therapy