Nov. 3 (HealthDay News) -- A potentially deadly stomach infection is on the rise outside of hospital settings, especially among the elderly, researchers warn.

The germ that causes the condition, known as Clostridium difficile, can create serious symptoms, including diarrhea and an inflammation of the colon, that can be fatal. The infection can be difficult to treat because the bacteria have become immune to some drugs.

The bacteria have been found mostly in hospitals, nursing homes and similar facilities.

"Recent reports have shown increasing incidence and severity of C. difficile infection, especially in the older population," Dr. Darrell Pardi, a Mayo Clinic gastroenterologist and senior author of a study on the situation, said in a Mayo news release. "Our study examines why the cases are on the rise and who is getting the infection."

The findings were presented recently at the American College of Gastroenterology annual meeting, in San Diego.

The researchers examined 385 cases of disease caused by the germ from 1991 to 2005 to see if more were being acquired in places other than a hospital.

They found that people who got sick outside of a hospital were younger -- a median of 50 years old versus 72 -- and had less severe cases.

"The growing incidence of C. difficile infection in both inpatient and outpatient settings could be linked to the increasing usage of antibiotics and to the possibility that C. difficile may be getting resistant to some of our newer antibiotics," Pardi said.

Health experts have gotten better at spotting the bacteria in hospitals and nursing homes, he said, but "now doctors and patients need to be more aware that you can get this infection as an outpatient and that a case of diarrhea or abdominal cramps at home could become serious."

The germ kills an estimated 5,000 people in the United States each year, according to the U.S. Centers for Disease Control and Prevention.

SOURCE: Mayo Clinic, news release, October 2009