What treatment is required if a pus swab is positive for Staphylococcus aureus?

Treatment for Staphylococcus aureus Positive Pus Swab

Incision and drainage is the primary treatment for purulent skin infections caused by Staphylococcus aureus, with antibiotic therapy indicated only in specific circumstances such as systemic symptoms, immunocompromise, or extensive disease. 1

Initial Management

• Incision and drainage is the recommended primary treatment for abscesses, carbuncles, and large furuncles caused by S. aureus 1
• Gram stain and culture of pus from abscesses are recommended to guide targeted therapy, though treatment without these studies is reasonable in typical cases 1
• For simple, localized skin infections without systemic symptoms, incision and drainage alone is often sufficient without antibiotics 1

When to Add Antibiotic Therapy

Antibiotics should be added to incision and drainage in the following scenarios:

• Presence of systemic inflammatory response syndrome (SIRS): temperature >38°C or <36°C, tachypnea >24 breaths/min, tachycardia >90 beats/min, or white blood cell count >12,000 or <400 cells/μL 1
• Markedly impaired host defenses 1
• Extensive or severe local infection 1
• Presence of signs of systemic illness 1
• Inadequate response to incision and drainage alone 1
• Concern for a cluster or outbreak 1

Antibiotic Selection

For Methicillin-Susceptible S. aureus (MSSA):

• First-line: Penicillinase-resistant penicillins (flucloxacillin, dicloxacillin) 2
• Alternatives:
  • First-generation cephalosporins (cefazolin, cephalexin) 2
  • Clindamycin 600 mg IV or PO three times daily 1

For Methicillin-Resistant S. aureus (MRSA) or if MRSA prevalence is high:

• Intravenous options:
  • Vancomycin 1, 3
  • Daptomycin 4 mg/kg/dose IV once daily 1
  • Telavancin 10 mg/kg/dose IV once daily 1
• Oral options:
  • Linezolid 600 mg twice daily 1, 3
  • Clindamycin (if susceptible) 1, 2
  • Trimethoprim-sulfamethoxazole 2

Duration of Therapy

• 7-14 days of antibiotic therapy is recommended for skin and soft tissue infections requiring antibiotics 1
• Treatment duration should be individualized based on clinical response 1
• For simple abscesses treated with incision and drainage alone, no antibiotics may be needed 1

Special Considerations

For Recurrent S. aureus Infections:

1. Search for local causes (e.g., pilonidal cyst, hidradenitis suppurativa, foreign material) 1
2. Early drainage and culture of recurrent abscesses 1
3. Consider a 5-10 day course of an antibiotic active against the isolated pathogen 1
4. Consider decolonization regimen:
   • Intranasal mupirocin twice daily for 5-10 days 1
   • Daily chlorhexidine washes for 5-14 days 1
   • Daily decontamination of personal items 1

For Pediatric Patients:

• For minor skin infections, mupirocin 2% topical ointment can be used 1
• Tetracyclines should not be used in children <8 years of age 1
• For hospitalized children with complicated skin infections, vancomycin is recommended 1

Prevention Measures

• Keep draining wounds covered with clean, dry bandages 1
• Maintain good personal hygiene with regular bathing and hand cleaning 1
• Avoid reusing or sharing personal items that have contacted infected skin 1
• Focus cleaning efforts on high-touch surfaces using appropriate cleaners 1

Common Pitfalls to Avoid

• Treating all S. aureus positive cultures with antibiotics when incision and drainage alone may be sufficient 1
• Failing to obtain cultures in patients with recurrent infections, as this may lead to inappropriate antibiotic selection 1
• Overlooking the need for source control (drainage) when using antibiotics 1
• Not considering MRSA coverage in areas with high MRSA prevalence 1
• Neglecting to address environmental and personal hygiene factors in recurrent infections 1