What is the coverage for Methicillin-resistant Staphylococcus aureus (MRSA) oral cellulitis?

From the Guidelines

For MRSA oral cellulitis, the recommended treatment is linezolid at a dose of 600mg twice daily for 7-14 days, depending on severity, as it is the most recent and highest quality recommendation. Alternatives include trimethoprim-sulfamethoxazole (TMP-SMX) at a dose of 1-2 double-strength tablets (160mg/800mg) twice daily, doxycycline 100mg twice daily, or tedizolid, as suggested by the 2018 WSES/SIS-E consensus conference 1. For severe cases or patients unable to take oral medications, consider intravenous daptomycin, IV linezolid, IV ceftaroline, IV dalbavancin, IV vancomycin, IV tigecycline, or IV tedizolid. It's essential to obtain cultures before starting antibiotics when possible to confirm the diagnosis and susceptibility. MRSA cellulitis typically presents with erythema, swelling, warmth, and tenderness, often with purulent drainage. These antibiotics are effective because they target the bacterial cell wall or protein synthesis mechanisms that MRSA hasn't developed resistance against, unlike beta-lactam antibiotics such as penicillins and cephalosporins. Patients should complete the full course of antibiotics even if symptoms improve quickly, and should seek immediate medical attention if fever develops, the affected area expands rapidly, or if they develop systemic symptoms like high fever or hypotension.

Some key points to consider when treating MRSA oral cellulitis include:

• The importance of empirical therapy for CA-MRSA pending culture results, as recommended by the Infectious Diseases Society of America 1
• The need for individualized treatment based on the patient's clinical response, as suggested by the 2018 WSES/SIS-E consensus conference 1
• The potential for resistance to glycopeptides, which may affect the efficacy of these antibiotics, as noted in the 2018 WSES/SIS-E consensus conference 1
• The advantages of early intravenous-to-oral switch with linezolid, which has excellent tissue penetration and high bioavailability, as mentioned in the 2018 WSES/SIS-E consensus conference 1

From the Research

Coverage for Methicillin-resistant Staphylococcus aureus (MRSA) Oral Cellulitis

• The treatment of MRSA oral cellulitis should cover Streptococcus and methicillin-sensitive S. aureus, with expansion for MRSA in cases of cellulitis associated with specific risk factors 2.
• For MRSA infections, vancomycin remains an acceptable treatment option, and other effective drugs include linezolid, tigecycline, telavancin, ceftaroline, and daptomycin 3, 4.
• Oral antibiotics such as linezolid, TMP-SMX, and tetracyclines have been used to treat MRSA skin and soft tissue infections, including cellulitis, with a high clinical cure rate 5.
• The selection of the most appropriate antibiotic will depend on local antibiotic resistance, type of infection, potential adverse effects, and cost for the individual 5, 4.
• New MRSA-active antibiotics, such as ceftaroline, tedizolid, telavancin, dalbavancin, and oritavancin, have been introduced, but further studies are required for more invasive infections, such as bacteremia and endocarditis 6.

Antibiotic Options

• Vancomycin: remains an acceptable treatment option for MRSA infections 3, 4, 6.
• Linezolid: effective for the treatment of complicated MRSA skin and soft tissue infections, including cellulitis 5, 4, 6.
• Ceftaroline: noninferior to comparator agents in the treatment of acute bacterial skin and skin structure infections, including cellulitis 4, 6.
• Tedizolid: more potent than linezolid, with improved pharmacokinetics and reduced toxicity, and active against cfr-containing S. aureus 6.
• Telavancin: noninferior to comparators for acute bacterial skin and skin structure infections, including cellulitis 4, 6.
• Dalbavancin and oritavancin: administered once weekly, and noninferior to comparators for acute bacterial skin and skin structure infections, including cellulitis 6.

Treatment Considerations

• Treatment of MRSA oral cellulitis should be individualized based on the severity of the infection, the presence of underlying medical conditions, and the susceptibility of the infecting organism to antibiotics 2, 4.
• The duration of treatment for MRSA oral cellulitis is typically 5-7 days, but may be extended if symptoms persist 2.
• Addressing predisposing factors, such as poor oral hygiene, can minimize the risk of recurrence of MRSA oral cellulitis 2.