The number of cases of methicillin-resistant Staphylococcus aureus (MRSA) infections has increased by more than 90 percent during the last decade, according to research from Princeton University.

In 2006, there were 278,203 reported cases of MRSA-related infection, more than double the number in 1999, according to the study. The growing number of MRSA cases reflects the increasing resistance of Staphylococcus bacteria to antibiotics.

The study also shows that hospital-associated MRSA infections, occurring mostly in patients with weakened immune systems, have been more common than community-associated MRSA infections, occurring among those who pick up the bacteria in fitness centers, common restrooms and other public places.