From the Guidelines
For the treatment of cellulitis caused by MRSA, the most effective oral antibiotics include trimethoprim-sulfamethoxazole (TMP-SMX), clindamycin, doxycycline, minocycline, and linezolid, as recommended by the Infectious Diseases Society of America 1. When choosing an oral antibiotic for MRSA cellulitis, it's essential to consider the severity of the infection, patient comorbidities, and local resistance patterns.
- TMP-SMX is a first-line option, typically dosed at 1-2 double-strength tablets twice daily for 7-14 days.
- Clindamycin is another good choice, usually prescribed as 300-450 mg four times daily for 7-14 days, though increasing resistance limits its use in some regions.
- Doxycycline or minocycline (100 mg twice daily for 7-14 days) are alternatives with good MRSA coverage.
- Linezolid is highly effective but expensive, dosed at 600 mg twice daily for 7-14 days, and requires monitoring for myelosuppression with longer use. It's crucial to note that these antibiotics are effective because they target mechanisms that MRSA hasn't developed resistance to, unlike beta-lactam antibiotics such as methicillin, oxacillin, and most cephalosporins, which are ineffective against MRSA due to the mecA gene that alters penicillin-binding proteins 1. The treatment duration depends on infection severity, with uncomplicated cases typically requiring 7-10 days and more severe infections needing 10-14 days 1. In cases where empirical coverage for both b-hemolytic streptococci and CA-MRSA is desired, clindamycin alone or TMP-SMX or a tetracycline in combination with a b-lactam (e.g., amoxicillin) may be used 1. However, the choice of antibiotic should always be guided by the most recent and highest quality evidence, as well as local resistance patterns and patient-specific factors.
From the FDA Drug Label
Adult patients with infection due to MRSA should be treated with ZYVOX 600 mg q12h In limited clinical experience, 5 out of 6 (83%) pediatric patients with infections due to Gram-positive pathogens with MICs of 4 µg/mL treated with ZYVOX had clinical cures.
The oral antibiotic linezolid (ZYVOX) covers MRSA for the treatment of cellulitis, with a recommended dosage of 600 mg orally every 12 hours for adult patients 2.
Clindamycin is also indicated in the treatment of serious infections due to susceptible strains of streptococci, pneumococci, and staphylococci
Clindamycin may also be used to treat MRSA infections, although its effectiveness depends on the susceptibility of the specific strain 3.
From the Research
Oral Antibiotics for Cellulitis that Cover MRSA
Oral antibiotics that cover Methicillin-resistant Staphylococcus aureus (MRSA) for the treatment of cellulitis include:
- Trimethoprim-sulfamethoxazole (TMP-SMX) 4, 5, 6
- Clindamycin 4, 5
- Minocycline 7, 6
- Doxycycline 7, 6
- Linezolid 8, 6
Efficacy of Oral Antibiotics
The efficacy of these oral antibiotics in treating cellulitis caused by MRSA has been studied:
- Trimethoprim-sulfamethoxazole (TMP-SMX) has been shown to have a high treatment success rate for cellulitis, especially in areas with a high prevalence of community-associated MRSA infections 4
- Clindamycin has been found to have a similar cure rate to TMP-SMX for uncomplicated skin infections, including cellulitis 5
- Minocycline is often preferred over TMP-SMX or doxycycline for the treatment of community-acquired MRSA skin and soft-tissue infections, including cellulitis 7
- Linezolid has been used in combination with rifampin to treat MRSA preseptal cellulitis that did not respond to vancomycin treatment 8
Considerations for Antibiotic Selection
When selecting an oral antibiotic to treat cellulitis caused by MRSA, considerations include:
- Local antibiotic resistance patterns
- Type and severity of infection
- Potential adverse effects
- Cost of treatment 6