A person acquires MRSA by coming into contact with someone who has methicillin-resistant staphylococcus aureus bacteria on his skin or by touching an object bearing the bacteria, according to WebMD. While approximately 2 percent of the population carries the bacteria, most don't develop an infection.
Methicillin-resistant staphylococcus aureus is a bacterium that often causes infection in people with weakened immune systems, explains WebMD. MRSA infections commonly develop around wounds or in areas where invasive devices, such as catheters or feeding tubes, are inserted into the body. Discovered in 1961, MRSA has become resistant to many antibiotics, making it difficult to treat.