What is the best antibiotic treatment for skin infections suspected to be caused by Methicillin-resistant Staphylococcus aureus (MRSA)?

From the Guidelines

For skin infections suspected to be caused by Methicillin-resistant Staphylococcus aureus (MRSA), Bactrim (trimethoprim-sulfamethoxazole) is a good antibiotic option, with a standard adult dosage of one double-strength tablet (160mg/800mg) taken twice daily for 7-10 days, as recommended by the Infectious Diseases Society of America 1. The choice of antibiotic should be based on the severity of the infection, patient allergies, and local resistance patterns. Some key points to consider when treating skin infections suspected to be caused by MRSA include:

• Incision and drainage of abscesses is the primary treatment, with antibiotic therapy recommended for abscesses associated with severe or extensive disease, systemic illness, or lack of response to incision and drainage alone 1.
• Empirical therapy for CA-MRSA is recommended for outpatients with purulent cellulitis, with options including clindamycin, TMP-SMX, doxycycline, and linezolid 1.
• For hospitalized patients with complicated skin and soft tissue infections (SSTIs), empirical therapy for MRSA should be considered, with options including intravenous vancomycin, linezolid, daptomycin, and telavancin 1. It's also important to note that MRSA has developed resistance to beta-lactam antibiotics, which is why alternative antibiotics with different mechanisms of action are needed 1. Proper wound care, including incision and drainage of abscesses, is essential alongside antibiotic therapy. The treatment choice may need to be adjusted based on culture results when available. In general, the goal of treatment is to reduce morbidity, mortality, and improve quality of life for patients with skin infections suspected to be caused by MRSA.

From the FDA Drug Label

The cure rates in microbiologically evaluable patients with MRSA skin and skin structure infection were 26/33 (79%) for linezolid-treated patients and 24/33 (73%) for vancomycin-treated patients Table 18 Cure Rates at the Test-of-Cure Visit for Microbiologically Evaluable Adult Patients with Complicated Skin and Skin Structure Infections PathogenCured ZYVOXn/N (%)Oxacillin/Dicloxacillinn/N (%) Methicillin-resistant S aureus2/3 (67)0/0 (-) Table 19 Cure Rates at the Test-of-Cure Visit for Microbiologically Evaluable Adult Patients with Diabetic Foot Infections PathogenCured ZYVOXn/N (%)Comparatorn/N (%) Methicillin-resistant S aureus12/17 (71)2/3 (67)

Bactrim is not mentioned in the provided drug labels as a treatment for skin infections suspected to be caused by Methicillin-resistant Staphylococcus aureus (MRSA). The labels discuss the use of linezolid for treating MRSA infections.

• Linezolid appears to be effective against MRSA, with cure rates of 79% and 71% in two different studies 2.
• Vancomycin is also effective against MRSA, with a cure rate of 73% 2.
• Oxacillin/Dicloxacillin had no patients with MRSA in the study, so no conclusion can be drawn about its effectiveness against MRSA 2. The FDA drug label does not provide information about the effectiveness of Bactrim (trimethoprim/sulfamethoxazole) for skin infections suspected to be caused by MRSA.

From the Research

Antibiotic Treatment for Skin Infections Suspected to be Caused by MRSA

• The choice of antibiotic treatment for skin infections suspected to be caused by Methicillin-resistant Staphylococcus aureus (MRSA) depends on the severity of the infection and local susceptibility patterns 3.
• For community-acquired MRSA, options include macrolides, clindamycin, and cotrimoxazole (also known as trimethoprim-sulfamethoxazole) 3, 4.
• Vancomycin is typically reserved for treatment of infections caused by multiresistant MRSA strains and for patients with suspected endocarditis or severe sepsis 3, 5.
• Newer antibiotics such as linezolid and quinopristin/dalfopristin have shown good activity against MRSA, but should only be used with specialist advice 3, 5.
• Bactrim (trimethoprim-sulfamethoxazole) may be an option for treating skin infections suspected to be caused by MRSA, especially in cases where the infection is community-acquired 4, 6.

Considerations for Treatment

• The severity of the infection determines the choice of treatment, with more severe infections requiring intravenous antibiotics such as vancomycin or ceftriaxone 3, 4.
• Supportive management, including removal of any infected foreign bodies, surgical drainage of walled-off lesions, and regular wound cleaning, plays a vital role in ensuring cure 4.
• The emergence of community-associated MRSA has represented a considerable challenge in the treatment of acute bacterial skin and skin-structure infections (ABSSSIs) 7.
• The choice of antibiotic should be guided by local susceptibility patterns and the results of culture and sensitivity testing, if available 3, 5.