What is the recommended treatment for a patient with Staphylococcus species (Staphylococcus sp) on urine culture?

Management of Staphylococcus Species in Urine Culture

In most cases, Staphylococcus species isolated from urine represents contamination or asymptomatic colonization that should NOT be treated, as antimicrobial therapy provides no clinical benefit and promotes resistance. 1, 2, 3

Initial Assessment: Distinguish True Infection from Contamination

Key Clinical Questions to Answer:

Does the patient have urinary symptoms?

• Symptomatic patients with dysuria, frequency, urgency, suprapubic pain, fever, or flank pain require treatment 2
• Asymptomatic patients should NOT be treated in nearly all circumstances 1, 2, 3

Which Staphylococcus species was isolated?

• S. aureus: More likely to represent true infection, especially if ≥50,000 CFU/mL as a single pathogen 2, 4
• S. epidermidis: Most commonly represents skin contamination and should rarely be treated 3
• S. saprophyticus: Common true pathogen in young women with acute cystitis 5, 6
• Other coagulase-negative staphylococci: Usually contaminants 3, 7

What are the patient's risk factors?

• Urinary catheterization (especially ≥2 weeks) increases likelihood of true infection 2, 4, 8
• Recent urological instrumentation or procedures 4, 8
• Urological abnormalities or stones 4, 6
• Male sex and older age 4
• Diabetes mellitus 4

When Treatment IS Indicated

Symptomatic UTI with Confirmed Staphylococcus

For S. aureus:

• Obtain susceptibility testing and use targeted therapy 2
• MSSA: Cefazolin or antistaphylococcal penicillins (nafcillin, oxacillin) 2
• MRSA: Vancomycin or daptomycin 2
• Penicillin allergy: Ciprofloxacin or clindamycin for MSSA 2
• Duration: 7 days if prompt symptom resolution; 10-14 days if delayed response 2

For S. saprophyticus:

• Treat as typical acute cystitis with standard UTI antibiotics 5, 6
• Note: S. saprophyticus is resistant to nalidixic acid 5

Catheter-Associated Staphylococcal Bacteriuria

Critical management step:

• Replace the catheter if it has been in place ≥2 weeks before starting antibiotics, as biofilm formation prevents antibiotic penetration 2
• Antibiotic therapy alone will likely fail without catheter replacement 2

Pre-Procedure Prophylaxis (ONLY Exception for Asymptomatic Bacteriuria)

Screen and treat ONLY before endoscopic urologic procedures with anticipated mucosal trauma:

• Obtain pre-procedure urine culture 1, 2
• Administer 1-2 doses of targeted antimicrobial 30-60 minutes before procedure 1, 2
• This is the ONLY indication for treating asymptomatic staphylococcal bacteriuria 1, 2

When Treatment is NOT Indicated

Do NOT Screen or Treat in These Populations:

• Elective non-urologic surgery (including cardiac surgery) 1, 9
• Patients with indwelling catheters (short-term <30 days or long-term) 1
• Spinal cord injury patients 1
• Elderly patients in long-term care 1
• Patients with diabetes 1
• Patients with cognitive impairment 1

Exception: Pregnant women with asymptomatic bacteriuria should be treated 3

Special Consideration: Rule Out S. aureus Bacteremia

When S. aureus is isolated from urine, consider whether this represents hematogenous seeding:

• S. aureus bacteriuria can be associated with concurrent bacteremia in 13% of cases 8
• Higher risk with urological instrumentation 4, 8

Obtain blood cultures if:

• Patient has fever, persistent symptoms, or systemic signs of infection 4
• Recent urological instrumentation 4
• Patient appears clinically ill 4

However, routine blood cultures are NOT recommended in well-appearing patients with asymptomatic S. aureus bacteriuria 4

If S. aureus bacteremia is confirmed:

• Consider transesophageal echocardiography for high-risk patients (persistent bacteremia ≥48 hours, persistent fever, metastatic infection, cardiac devices) 2
• Minimum 14 days treatment if uncomplicated; 4-6 weeks if complicated or endocarditis present 2

Common Pitfalls to Avoid

Do not treat S. epidermidis or other coagulase-negative staphylococci unless:

• Clear urinary symptoms are present AND
• Proper specimen collection technique was used AND
• Patient has urological abnormalities or indwelling devices 3

Do not use vancomycin empirically for presumed catheter-associated infections when cultures are negative 3

Do not continue antibiotics if repeat culture shows persistent staphylococcal bacteriuria in asymptomatic patients—this represents colonization, not treatment failure 1, 4

Monitoring and Follow-Up

For treated symptomatic infections:

• Assess clinical response within 48-72 hours 2
• Adjust antibiotics based on culture and susceptibility results 2

Consider repeat urine culture in:

• Patients with urinary catheterization 4
• Patients with urological abnormalities 4
• Patients with diabetes 4
• Prior to planned bladder instrumentation 4

Median duration of staphylococcal bacteriuria in catheterized patients is 4.3 months, and persistent colonization can lead to subsequent invasive infection up to 12 months later 8. However, the efficacy of treating asymptomatic persistent bacteriuria to prevent late infection remains unproven 8.