5. Gyms: Hot, sweaty people sharing equipment and showers makes MRSA feel right at home at these public facilities.

The Centers for Disease Control and Prevention estimate that two in 100 people carry the MRSA staph germ. About 33 percent of people carry staph in their noses but don’t become ill. There are no totals on how many people get the disease in the United States.

The good news is that the CDC reports MRSA infections in healthcare facilities are decreasing. A study published in JAMA Internal Medicine showed that life-threatening MRSA infections (so-called “invasive” situations) are waning. The report indicates that hospital-contracted MRSA infections were down 54 percent from 2005 to 2011, a drop of more than 30,000 infections from previous years. That meant approximately 9,000 fewer deaths from MRSA-related infections than before. That correlates with an earlier study from the National Healthcare Safety Network that discovered MRSA bloodstream infections at hospitals dropped by half in the decade from 1997 to 2007.

No doubt these situations reflect an increasing awareness of the possibility of MRSA and quick action on the part of hospitals to quarantine suspected cases to prevent further outbreaks.

The immune-compromised are at particular risk for MRSA infection, which is why healthcare facilities were on the front lines of early infections. Many of the first MRSA patients were in long-term healthcare facilities like nursing homes or were hospitalized frequently, on kidney dialysis, in the middle of cancer treatments or had recently received surgery. It was also found that intravenous drug users were among the largest subset of people who were prone to MRSA infections.