From the Guidelines
Mupirocin is generally more effective than bacitracin for treating MRSA infections. Mupirocin (available as 2% ointment or cream) specifically targets bacterial protein synthesis and has demonstrated superior efficacy against methicillin-resistant Staphylococcus aureus compared to bacitracin 1. For MRSA skin infections, apply mupirocin three times daily for 7-10 days to the affected area after cleaning with mild soap and water. For nasal decolonization, mupirocin 2% nasal ointment should be applied inside each nostril twice daily for 5-7 days. Mupirocin works by inhibiting bacterial isoleucyl-tRNA synthetase, preventing protein synthesis in bacteria. While bacitracin has some activity against gram-positive bacteria including Staphylococcus, it has shown higher rates of resistance among MRSA strains and generally demonstrates lower efficacy rates in clinical practice. Additionally, mupirocin has better tissue penetration and maintains activity in the presence of wound exudates, making it the preferred topical agent for confirmed MRSA infections.
Some key points to consider when treating MRSA infections include:
- The use of mupirocin for minor skin infections, such as impetigo, and secondarily infected skin lesions, such as eczema, ulcers, or lacerations 1
- The importance of incision and drainage for cutaneous abscesses, with antibiotic therapy recommended for abscesses associated with certain conditions, such as systemic toxicity or rapid progression 1
- The use of oral antibiotics, such as clindamycin, doxycycline, or TMP-SMX, for empirical therapy of CA-MRSA infections 1
- The need to consider local epidemiology and the type of skin and soft tissue infection when selecting empirical therapy 1
It's also important to note that the Infectious Diseases Society of America recommends mupirocin as a topical treatment for impetigo and ecthyma, and as an alternative for penicillin-allergic patients or infections with MRSA 1. Overall, mupirocin is the preferred topical agent for treating MRSA infections due to its superior efficacy and better tissue penetration.
From the FDA Drug Label
Mupirocin is active against a wide range of gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA). There is no information about bacitracin in the provided drug label. The label only discusses the effectiveness of mupirocin against MRSA, stating it is active against this bacterium.
- Mupirocin is effective against MRSA, but the label does not compare it to bacitracin. Since there is no direct comparison between mupirocin and bacitracin in the label, no conclusion can be drawn about which one is more effective 2.
From the Research
Effectiveness of Mupirocin and Bacitracin in Treating MRSA
- There are no studies provided that directly compare the effectiveness of bacitracin and mupirocin in treating Methicillin-resistant Staphylococcus aureus (MRSA) [(3,4,5,6,7)].
- However, the provided studies demonstrate the effectiveness of mupirocin in treating MRSA infections [(3,4,5,6,7)].
- Mupirocin has been shown to be highly effective in eliminating MRSA in burn wounds [(3,4)] and in reducing nasal colonization with MRSA [(5,6)].
- The development of mupirocin resistance is a concern, and its use should be judicious to minimize the risk of resistance [(5,7)].
- There is no evidence provided on the effectiveness of bacitracin in treating MRSA, making it difficult to compare its effectiveness with mupirocin [no references].
Mupirocin Resistance
- Mupirocin resistance can reduce the effectiveness of decolonizing strategies for S. aureus or MRSA [(5,7)].
- Low-level resistant isolates may initially be eradicated as effectively as susceptible isolates, but recolonization appears to be more usual 5.
- Increased use of mupirocin has been associated with the emergence of resistance through enhanced selective pressure and cross-transmission 7.