MRSA is a type of Staphyloccocal infection that is resistant to the common “first-line” antibiotics that are used to treat bacterial infections. The major difference between MRSA and other Staphyloccocus strains is that MRSA has developed resistance to the common antibiotics that doctors commonly use to treat bacterial infections. MRSA becomes resistant to these antibiotics when it acquires a mutated gene that allows it to replicate in the presence of the antibiotic. Once it replicates, the MRSA bacterium passes on this resistance to its daughter cells and so on, until there is a whole population of resistant cells that the antibiotic cannot eradicate.
Like with most Staph infections, someone who is colonized with MRSA can spread MRSA to other people. According to the U.S. Centers for Disease Control (CDC), in 2004, 63% of all reported Staph infections in the United States were caused by MRSA (CDC, 2007) which means that most of us have either been exposed to MRSA at some point in our lives. MRSA infections get started when the skin is cut, rubbed or compromised in some way, allowing the bacteria access to the underlying tissues and causing a red, swollen, and painful area on the skin that can release pus or other fluids.
Due to its antibiotic resistance, MRSA infections in patients in health care facilities are a major concern and result in the most MRSA-related deaths. These cases usually begin as a nominal skin infection that rapidly spreads to the internal organs such as the heart and lungs. People most at risk for contracting an MRSA infection are patients in healthcare facilities, children in daycare, members of the military, and athletes. In recent years, MRSA infections have been increasing among athletes. In 2005, The New England Journal of Medicine published a study showing that professional football players were prone to a unique strain of MRSA that entered the skin through turf abrasions (http://www.nejm.org/doi/full/10.1056/NEJMoa042859). In studies funded by the Texas State Department of Health, researchers concluded that football players were 16 times more likely to develop MRSA than the average person in the US (http://www.dshs.state.tx.us/idcu/health/antibiotic_resistance/mrsa/conference/).