The microbe MRSA, or methicillin-resistant Staphylococcus aureus, is an antibiotic-resistant strain of the bacterium commonly known as staph. Approximately one third of people carry Staphylococcus aureus on their skin or in their nose, but the bacterium does not cause any problems until it enters the skin through a cut or abrasion. Usually staph infections can be treated easily with antibiotics. However, MRSA has become common in recent decades, which makes treatment of such an infection much more difficult.
Skin Infections
Staph infections are most commonly found on the skin. The infection may start as a pimple or boil that becomes red, swollen, painful, or warm to the touch; or starts to drain pus. It may also be accompanied by a fever. Staph infections are identified by sampling the wound and culturing the bacteria in the laboratory, a process that takes roughly 48 hours. Once identified, the bacteria can be tested to see if they are sensitive to different antibiotics before the proper treatment is chosen. A diagnosis of MRSA makes the treatment more difficult as a number of related antibiotics will also be ineffective. Maintaining proper hygiene, including hand washing, and keeping wounds clean, dry and covered, help prevent MRSA skin infections.
Pneumonia
MRSA can also cause pneumonia, usually in patients who already have a compromised immune system due to the flu or hospitalization. Bacteria living in the nose can be inhaled, and if the lungs are already weakened by the flu or sickness, staph bacteria can colonize and grow. Pneumonia is characterized by a productive cough, shortness of breath or painful inhalation, fever, and occasionally stabbing pains when inhaling or coughing.
Sepsis
Sepsis is an extremely serious condition that occurs when the reaction of the immune system interferes with the blood's ability to deliver nutrients. If the blood is overwhelmed with signals from the immune system, it will start to form clots, potentially blocking blood flow to organs. Sepsis is diagnosed by blood cultures and must be treated in a hospital, usually in the intensive care unit, and involves intravenous antibiotics and fluids, and occasionally respirator support. Rapid diagnosis and treatment are key, because one third of patients with sepsis will die from the condition.
References
- National Institute of Allergy and Infectious Diseases: MRSA
- "Proceedings of the National Academy of Sciences, U.S.A." The evolutionary history of methicillin resistant Staphylococcus aureus (MRSA). Mark Enright et al. 2002.
- Centers for Disease Control and Prevention: MRSA in health care settings
- Medline Plus: Sepsis
