The mortality estimates of the germ -- methicillin-resistant Staphylococcus aureus, also known as MRSA -- exceed the individual mortality rates in the United States for AIDS, Parkinson’s disease, emphysema and homicide, The New York Times reported Wednesday.

R. Monina Klevens, leader of the U.S. government study -- published in Wednesday's issue of The Journal of the American Medical Association -- said the infection appears to be twice as prevalent as previously believed.

"This is a significant public health problem. We should be very worried," Scott Fridkin, a medical epidemiologist at the U.S. Centers for Disease Control and Prevention, told The Washington Post.

The researchers said the study of the bacteria's prevalence only included the most serious infections.

"It's really just the tip of the iceberg," said Elizabeth A. Bancroft, a medical epidemiologist at the Los Angeles County Department of Public Health who authored an editorial that accompanied the study. "It is astounding."