A deadly bacteria known as C. difficile has found its way from hospitals to local doctors' offices, At large health centers, the germ has been a concern for years, but a new study shows a substantial number of people who contracted the bug had not been hospitalized but merely visited their physician or dentist.

Nearly half a million Americans were infected in various locations in one year, CNN reported. Health authorities attribute up to 15,000 deaths to C. difficile, which can cause deadly diarrhea. In a 2013 investigation conducted in Ohio, experts found the bacteria in six out of seven outpatient facilities. The germs were most likely to be on patients' chairs and examining tables.

The Atlanta-based Centers for Disease Control, the United States' leading national public health institute, has meanwhile announced a new study to determine if people are being infected at doctors' offices.

Dr. Cliff McDonald, a medical epidemiologist at the CDC, said determining how bugs spread was "an important issue."

"We need to understand better how people are getting C. diff," McDonald said.

C. difficile -- or C. diff -- is short for Clostridium difficile, USA Today reported. The bacteria in 2010 affected twice as many patients as it did ten years earlier, according to CDC statistics.

In 2011, about 29,000 patients with the bacteria died within a month of becoming sick. A third of infections occurs in people 65 and older, and senior citizens also account for most of the deaths caused by C. difficile.

While antibiotics are often effective in treating the germ, toxins released by the bacteria can harm the colon, the CDC's Michael Bell said. The damage is often so severe that doctors have to remove the organ, added Bell, a specialist in drug-resistant pathogens and hospital-acquired infections.

"C. difficile infections cause immense suffering and death for thousands of Americans each year," CDC Director Tom Frieden said.

Health experts caution that patients need to wash their hands with soap and water after visiting the doctor's office because alcohol-based gels do not get rid of C. difficile.