Methicillin-resistant Staphylococcus aureus, commonly known as MRSA, is a contagious and treatment-resistant strain of Staphylococcus that is often contracted in hospital settings and that annually kills over 18,000 people in the United States. According to the Centers for Disease Control, one in three people carry staph in their noses, with one in fifty testing positive for MRSA. It is not known how many people in the general public have MRSA on their skin.
MRSA is most commonly encountered in hospitals and other healthcare settings. Dialysis patients and people who've had invasive surgical procedures are especially at risk of infection, as reported by the Mayo Clinic. Precautions that can protect healthy people from infection include the thorough sterilization of medical equipment and fixtures, frequent hand washing, and the use of universal precautions such as gloves and gowns, in the presence of infected patients.
Although MRSA is most often contracted in hospitals, nursing homes and dialysis centers, around 14 percent of infected people appear to have gotten the infection somewhere outside of the usual clinical settings. This "community-associated" MRSA is a growing risk to the general public. According to WebMD, one study of children in south Texas showed a 14-fold increase in cases between 1999 and 2001 alone.