What are the recommended antibiotics for treating mediastinitis?

Recommended Antibiotics for Mediastinitis

For mediastinitis, the recommended antibiotic therapy depends on the etiology, with vancomycin (30-60 mg/kg/day IV in 2-4 divided doses) being the primary treatment for post-surgical MRSA-associated mediastinitis, while fungal mediastinitis may require amphotericin B followed by itraconazole. 1

Treatment Based on Etiology

Post-Surgical/Post-Traumatic Mediastinitis

• For MRSA-associated mediastinitis (common after cardiac surgery), vancomycin 30-60 mg/kg/day IV in 2-4 divided doses is the primary treatment 2, 1
• Alternative options include:
  • Teicoplanin 6-12 mg/kg/dose IV q12h for three doses, then once daily 2
  • Linezolid 600 mg IV/PO q12h 2
  • Daptomycin 6-10 mg/kg/dose IV once daily 2
• For polymicrobial infections (common after esophageal perforation), broad-spectrum beta-lactams alone or combined with metronidazole to cover both gram-positive, gram-negative, and anaerobic bacteria 3
• Duration of therapy should be 4-6 weeks for post-surgical mediastinitis 1

Fungal Mediastinitis

• For severe histoplasmosis-related mediastinitis with obstructive complications:
  • Initial therapy: Amphotericin B (0.7-1.0 mg/kg/day) 1
  • After clinical improvement: Transition to itraconazole 200 mg once or twice daily 1
• For less severe cases: Itraconazole 200 mg once or twice daily for 6-12 months 1
• Consider prednisone 40-80 mg daily for 2 weeks in cases with major airway obstruction 1

Fibrosing Mediastinitis

• Antifungal treatment is generally not recommended as most authorities believe it does not improve outcomes 2, 1
• A 12-week trial of itraconazole 200 mg once or twice daily may be considered if clinical findings cannot differentiate fibrosing mediastinitis from granulomatous mediastinitis 2, 1
• Intravascular stents are recommended for selected patients with pulmonary vessel obstruction 2, 1

Special Considerations

Resistant Pathogens

• For multidrug-resistant gram-negative bacteria (Enterobacteriaceae) and non-fermenting bacteria (Pseudomonas, Acinetobacter), consider:
  • Polymyxins (e.g., colistin)
  • New tetracyclines
  • Newly developed combinations of beta-lactams and beta-lactam inhibitors 3

Renal Dysfunction

• For patients with renal dysfunction, therapeutic drug monitoring is recommended when using linezolid to maintain serum trough concentrations between 2 and 7 μg/mL 4

Duration of Therapy

• Post-surgical mediastinitis: 4-6 weeks of appropriate antibiotic therapy 1
• Granulomatous mediastinitis: 6-12 weeks of antifungal therapy 1
• Longer courses may be necessary based on clinical response and imaging findings 1

Adjunctive Therapies

• Surgical debridement is essential in addition to antibiotic therapy 5, 6
• Negative-pressure wound therapy (NPWT) has been associated with significantly less surgical failure than traditional treatment and may improve prognosis for patients with MRSA mediastinitis 7
• For fungal mediastinitis, corticosteroids might be beneficial in cases with significant inflammation and obstruction 1

Common Pitfalls to Avoid

• Failing to distinguish between granulomatous and fibrosing mediastinitis can lead to inadequate treatment 1
• Underestimating the severity of MRSA mediastinitis - MRSA infection has been identified as an independent risk factor for hospital mortality in poststernotomy mediastinitis 7
• Delayed diagnosis and treatment - early diagnosis and prompt, aggressive initial therapy are essential for optimal outcomes 5