According to Mayo Clinic, MRSA stands for methicillin-resistant staphylococcus aureus and is an infection caused by a strain of bacteria that is resistant to the antibiotics commonly used to treat ordinary staph infections. MRSA infections typically occur in patients who have been in a hospital or other health care settings.
MRSA infections start as small, red bumps that can quickly progress into deep, painful abscesses that require surgical draining, notes Mayo Clinic. In some cases, a MRSA infection remains on the skin; however, it can spread into the body. Once a MRSA infection has spread, it can cause infections in the bones, joints, surgical wounds, the bloodstream, heart valves and lungs.