Aggressive, drug-resistant staph infections contracted in hospitals or from other medical treatment are becoming scarcer, another sign of progress in a prevention effort that has become a national public health priority. In nine metro areas, cases of methicillin-resistant Staphylococcus aureus, or MRSA, fell about 16 percent between 2005 and 2008. That translates to a drop from about 32 cases per 100,000 to 26 cases per 100,000 people. The study by the Centers for Disease Control and Prevention did not address MRSA infections that occur in schools, locker rooms and other ordinary settings. Some reports have suggested those cases may be on the rise. MRSA often causes only a boil or skin infection. But researchers in the study focused on invasive cases that can become deadly, penetrating the bloodstream, flesh, lungs and bones.
