The Centers for Disease Control (CDC) in the United States says MRSA infections (methicillin-resistant Staphylococcus aureus) are more prevalent and invasive than previously thought.
In the CDC's first overall estimate of the invasive disease it is estimated that more than 94,000 Americans are infected by the super bug MRSA
MRSA is carried on the skin or in the nose of healthy people and has now escaped the hospital setting and is in the wider community.
Staph infections, including MRSA, usually start as small red bumps that look like pimples, boils or spider bites; these can quickly turn into deep, painful abscesses that require surgical draining.
Sometimes the bacteria remain confined to the skin but they can also burrow deep into the body, causing potentially life-threatening infections in bones, joints, surgical wounds, the bloodstream, heart valves and lungs.
Staph bacteria are generally harmless unless they enter the body through a cut or other wound, and even then they often cause only minor skin problems in healthy people.
However in older adults and people who are ill or have weakened immune systems, ordinary staph infections can cause serious illness called methicillin-resistant Staphylococcus aureus or MRSA.
The CDC says the overall incidence rate is an "astounding" 32 invasive infections per 100,000 people.
The CDC researchers say in 2005 MRSA was responsible for 18,650 deaths compared with around 16,000 from AIDS and are an important public health problem that can no longer be ignored.
MRSA is called a super bug because it is resistant to so many antibiotics; it can cause bloodstream infections, surgical site infections and pneumonia and has become the most common cause of soft tissue and skin infections among emergency department patients in the U.S.; it can cause serious, and potentially fatal invasive disease.
The study is published in the current issue of The Journal of the America Medical Association (JAMA).