Drug-resistant staph infection rates are highest among the elderly, according to a new study by researchers at the Centers for Disease Control and Prevention. The infections also are more common among the general population than experts previously believed.

Rates of MRSA infection were highest for those 65 and older – nearly 128 cases per 100,000 versus 31.8 per 100,000 persons for the general population, the study found. The number of deaths from MRSA exceeds the death toll attributed to HIV/AIDS, Parkinson’s, emphysema or homicide. The study was published in the Journal of the American Medical Association.

About 60% of Methicillin-resistant Staphylococcus aureus infections were found in community healthcare settings and nearly 27% were in hospitals. Nearly 14% of were infections were not associated with healthcare facilities, according to researchers led by Dr. R. Monina Klevens, an epidemiologist at the CDC.