WASHINGTON (AP) -- Doctors are increasingly concerned about drug-resistant staph bacteria that are increasingly acquiring "superbug" powers and causing far more serious illnesses than they have in the past.

These widespread germs, picked up in ordinary community settings, used to be easier to treat than the dangerous forms of staph found in hospitals and nursing homes.

Now, the germs causing outbreaks in schools, on sports teams and in other social situations are posing a growing threat. A CDC study finds that at least 10 percent of cases involving the most common community strain were able to evade the antibiotics typically used to treat them.

The germ is known as MRSA. People can carry it on their skin or in their noses with no symptoms and still infect others.

MRSA mostly causes skin infections. But doctors at a Washington conference say the germ can be life-threatening if it gets into the bloodstream, lungs or organs.

(Copyright 2008 by The Associated Press. All Rights Reserved.)