Sharing a hospital room with other sick patients dramatically increases the risk of acquiring a serious infectious disease compared to staying in a private room, Canadian researchers have discovered.

A new study led by infectious diseases expert Dr. Dick Zoutman says the chance of acquiring serious infections such as C. difficile (Clostridium difficile) rises with the addition of every hospital roommate.

"If you're in a two-, three- or four-bedded room, each time you get a new roommate your risk of acquiring these serious infections increases by 10 per cent," Dr. Zoutman, professor of Community Health and Epidemiology at Queen's, said in a news release.

"That's a substantial risk, particularly for longer hospital stays when you can expect to have many different roommates."

The findings are published on-line in the American Journal of Infection Control.

Zoutman suggests hospitals need to consider more private rooms in their planning.

"Despite other advances, multi-bedded rooms are still part of hospital design in the 21st century. Building hospitals with all private rooms is not yet the standard in Ontario or Canada - but it should be."

The researchers argue that althought it's expensive to build facilities with many private rooms, it's still cheaper in the long run because it can cost as much as $30,000 to treat a patient with stubborn, drug-resistant and hospital-acquired superbug.

For existing facilities with multi-bed rooms that are unable to take on major redesign, Zoutman suggests at least converting four-bed rooms to two-bed semi-privates, and changing semi-private rooms in high-risk areas to private rooms.

"One important way to improve patient safety in our hospitals is to reduce the number of roommates that patients are exposed to during their hospital stay," he said.

"Especially in acute care hospitals, where the risks are highest, we need to change our room configurations as much as current resources will allow, and strive to design and build new hospital facilities with entirely private rooms."