A hidden camera investigation by CBC News: Marketplace shows why many people get sicker in hospital.

Up to 250,000 Canadians end up with an infection from a hospital stay every year, and the infections kill about 8,000, according to research estimates by Dr. Dick Zoutman of Kingston General Hospital.

Overcrowding and understaffing contribute to the spread of infections, but lack of handwashing by doctors and nurses is another major cause of hospital infections, a 2004 report by the Canadian Institute of Health Information suggests.

CBC took a hidden camera into two hospitals chosen at random to find out what hospitals are doing to reduce the risk.

At St. Paul's Hospital in Vancouver, the camera showed doctors visited a patient with pneumonia and the superbug MRSA. Despite a warning posted on the door, the doctors touched the patient's table and left without washing their hands.

The doctors then went to the room of another highly contagious patient. Again, they did not wash their hands although hand gel sanitizers and sinks were readily available.

"If I saw this in my hospital, I would have a fit," infection control expert Dr. Michael Gardham of Toronto's University Health Network said of the footage.

"Physicians are always the worst offenders," Gardham added. "They're the least likely to wash their hands," a simple act that could prevent the majority of infections.

St. Paul's Hospital is trying to encourage handwashing, but it is difficult to make the message hit home, said Dr. Jeremy Etherington, the hospital's vice-president.

"I can promise you will see more [handwashing] as we continue our campaigns," Etherington said.

At St. Michael's Hospital in Toronto, the camera showed a health-care worker changing a bandage on an open wound and then moving on to the next patient without lathering up first. The scene is repeated throughout the hospital.

No one at St. Michael's would comment on the footage.