Methicillin-resistant Staphylococcus aureus (MRSA) refers to a strain of the bacteria Staphylococcus aureus that is resistant to a certain class of antibiotics known as beta-lactams. Penicillins, cephalosporins and carbapenems belong to this group. Until mid-1990s, MRSA infections were restricted to hospitalized patients, but today, these infections can be acquired in the community and are seen in otherwise healthy individuals. The Illinois Department of Health recommends antimicrobial therapy for severe MRSA infections that cannot be treated by drainage.
Clindamycin
Clindamycin is used to treat MRSA infections of the skin, blood or lungs and is available in capsule and liquid form. The medication is usually taken three to four times a day and the dosage and the length of the treatment depends on the severity of infection. Side effects include nausea, vomiting, heart burn and joint pain. According to the Rhode Island Department of Health, some MRSA isolates, especially those resistant to erythromycin, can become resistant to clindamycin as well. Hence, an alternative to clindamycin should be considered for erythromycin-resistant isolates.
Linezolid
Linezolid is effective against mid to moderate MRSA infections of skin and soft tissues, blood and lungs. Linezolid may be administered intravenously in the beginning of the infection, followed by oral therapy with improvement in the patient's condition. It is usually taken two times a day and common side effects include nausea, vomiting, taste abnormalities and reduced levels of blood platelets. The Illinois Department of Health warns that linezolid has a great potential for inappropriate use, inducing antimicrobial resistance and toxicity. This, along with the high cost of the medication, makes it unsuitable for routine use.
Tetracycline
Tetracyclines, such as minocycline and doxycycline, have been considered as effective alternatives to treat MRSA infections that do not require intravenous therapy. In a study published in "Antimicrobial Agents and Chemotherapy," September 2007, Dr. Jorg J. Ruhe found high rates of susceptibility to the tetracyclines among MRSA isolates at his institution.
Tetracycline is available in oral and suspension form and should be taken on an empty stomach. Diarrhea, stomach pain, increased thirst and loss of appetite are the possible side effects.
Trimethoprim/sulfamethoxazole (TMP/SMX)
Although not the first choice, Trimethoprim/sulfamethoxazole (TMP/SMX) may be considered as an alternative to treat mild MRSA infections, especially if other antibiotics are ruled out. However, a document published by the Ohio State University warns of serious side effects in patients with orthopedic implants, especially with long-term use of TMP/SMX. Other side effects include headache, nausea, diarrhea and depression.
Vancomycin
Vancomycin has been the most effective and reliable drug to treat MRSA infections and although, it is available in capsule and solution form, the Centers for Disease Control (CDC) states that vancomycin is useful only when given intravenously and is not effective for treatment of MRSA when taken by mouth. Thus, vancomycin is not recommended to treat non-serious MRSA infections like urinary tract infections and skin infections. Common side effects include nausea, dizziness, muscle spasms and breathing problems.
References
- Rhode Island Department of Health: Community Acquired MRSA
- Infectious Disease in Illinois: Methicillin-Resistant Staphylococcus aureus in Illinois
- "Antimicrobial Agents and Chemotherapy"; Tetracyclines as an Oral Treatment Option for Patients with Community Onset Skin and Soft Tissue Infections Caused by Methicillin-Resistant Staphylococcus aureus; Jörg J. Ruhe and Anupama Menon; September 2007
- Oregon Health and Sciene University: Oral Trimethoprim-Sulfamethoxazole for MRSA Infections
- CDC: Methicillin-resistant Staphylococcus aureus (MRSA)
