The Public Health Agency of Canada is warning hospitals across the country to be on alert for a highly drug-resistant bacterium that's infecting wounded soldiers in Afghanistan.

The agency is concerned returning troops could bring back the strain, called acinetobacter, from Afghanistan, and it could inadvertently be spread to civilian patients.

"It's the standard infection-control practices," agency spokesman Dr. Howard Njoo, director general of the Centre for Communicable Diseases and Infection Control, told CBC News. 

"Hospitals are very well versed in terms of the appropriate precautions to take for patients infected with any type of unusual bacteria. In this case, it's just a matter of making sure that they're aware of particular situations involving our soldiers coming back so that they can ensure that they take the right measures."

Hospitals are being advised by the agency to screen injured soldiers for the bug, and take infection-control precautions if they test positive.

Health officials are worried because the bacterium is difficult to treat. Several soldiers in civilian hospitals in Canada have already developed pneumonia from the drug-resistant strain of the bacterium, which scientists say likely originated in the Canadian-led trauma centre Kandahar Airfield.

Dr. Homer Tien, a Canadian surgeon working in Afghanistan, says no one is sure where acinetobacter came from, but it grows in soil and seems to pose a special threat to soldiers in war zones.

"The types of wounds that soldiers sustain in wars are different from what we see back home. We see explosives that blow dirt and soil into wounds," he told CBC News.

In sick or injured people, the bacteria can cause pneumonia, meningitis, sepsis and other infections. 

Doctors sounded alert

When Tien saw infections in wounded soldiers, he contacted the Public Health Agency of Canada. Together, they've described the military experience with the microbe, and have made recommendations on how to control it.

"As a physician — and certainly as a good citizen — we don't want to bring this organism back to Canada if we can avoid it," he said.

A few returning soldiers have been treated at Halifax's Queen Elizabeth II Health Sciences Centre.

Dr. Lynn Johnston, an infectious disease specialist at the hospital, says there is concern about a bacterium that is resistant to antibiotics infecting other patients. But she says this is one of the easier microbes to contain.

"Because we know these folks are arriving, it's not like the patient that comes to the emergency from goodness knows where," she said.

Johnston says Canada is benefiting from the experience of other countries. The U.S. and U.K. have both had hospital outbreaks linked to returning soldiers infected with the microbe.

Soldiers returning to Edmonton last year were the first known infections in Canada, but the bacteria did not spread to other patients.