Saskatoon’s health region is warning almost 2,200 patients who’ve received open-heart surgery over the last five years of a potential infection linked to a medical device.

The region says Health Canada, the Centers for Disease Control and Prevention, and the Food and Drug Administration are investigating reports a machine used to regulate blood temperature during open-heart surgery has been linked to rare bacterial infection, known as NTM — or non-tuberculous mycobacterium — infection. Letters are being sent to all patients who received the surgery in Saskatoon between 2011 and 2016.

The devices, which heat and cool blood, may have been contaminated during manufacturing, the health region says. Contaminated water tanks and pump assembly area were found at the manufacturing site.

The machines are used across Canada, the United States and Europe. Two patients in Canada and more than two dozen in the U.S. had contracted the NTM infection as of Oct. 31.

Symptoms — which include fever, redness, night sweats, muscle aches, weight loss or fatigue — can take up to four years to manifest and can take more than a year of antibiotics to treat.

A recent report by CDC showed 46 per cent of those who tested positive for the bacterium died. The relatively high mortality is likely due to the lengthy amount of time it takes for symptoms to show up.

None of the 2,173 patients who underwent open-heart surgery in Saskatoon since 2011 have so far been diagnosed with the infection, and no known infections have been reported in the province, according to the Saskatoon Health Region.

The chance of becoming infected is less than one per cent, but patients who experience the symptoms for more than a week are asked to contact their doctor.

No screening test exists to determine if a patient has been exposed to the NTM bacteria, the health region says.

The region says it’s following CDC and FDA recommendations regarding tests of the heating-cooling device and the replacement of tubing components in the machine. The region is also following the group’s protocols for cleaning and using filtered water.

--- with files from CTVNews.ca’s Misha Gajewski