Factors that increase the risk for developing methicillin-resistant Staphylococcus aureus (MRSA) include:

A. prior exposure to Mycobacterium tuberculosis.
B. prolonged hospitalization, especially in an intensive care unit.
C. failure to be vaccinated against any strain of hepatitis.
D. a history of a respiratory illness within the past 6 to 8 weeks.

Answer: B. prolonged hospitalization, especially in an intensive care unit.