Dr. Johann Pitout is tracking a multi-drug resistant strain of E. coli that multiples every 20 minutes in the lab. (CBC)

A doctor is trying to find out why so many people in Calgary have a strain of E. coli with the potential to create difficult-to-treat infections.

The multi-drug-resistant E. coli that Dr. Johann Pitout is tracking at Calgary Laboratory Services aren't the type found in tainted meat. The resistant strain started showing up outside the hospital, in the urine samples of otherwise healthy Calgarians.

"My culprit is a pink organism," Pitout said. "When you [grow it in a lab setting] it multiplies every 20 minutes, so it's very powerful."

The resistant strain is a type of ESBL-producing bacteria. That's short for extended spectrum beta-lactamase — enzymes produced by the bacteria that make them resistant to most antibiotics.

The strain started appearing in samples in the city in 2002, and by 2007, it was in the majority of samples. Hundreds of people were exposed to the same rare strain.

When Pitout dug deeper, he found a common source that he said was surprising.

"They had a recent history of travelling within six months of their infection to a non-U.S.A. destination," Pitout said. "We found some areas to be more of a risk or higher risk than other areas. Those that stood out were India and Pakistan, the Middle East and Africa."

Smouldering fire

It's unclear how people are getting it, whether from food, water or human-to-human spread.

It's urgent to find the answer, Pitout said, because this type of E. coli causes urinary tract or bladder infections, as well as a serious and potentially deadly infection of the kidneys known as urosepsis.

There is an expensive group of antibiotics that still work against the strain. But having to rely on it for uncomplicated urinary tract infections would add a huge cost to the health-care system and fuel further resistance, Pitout cautioned.

Urinary tract infections were the main reason 103,154 patients went to emergency rooms in Ontario during the fiscal year 2007 to 2008, according to the Canadian Institute for Health Information.

"We would like to make sure the fire doesn't get out of hand," Pitout said. "We know it's smouldering, and it's definitely starting to make small, little flames. We want to make sure it doesn't become a huge bush fire."

The researchers are planning a followup study to compare E. coli in people before they travel and afterward, to see if they pick up the resistant strain.

The team is also looking for any behaviours, such as consuming certain foods or drinks or taking over-the-counter antibiotics, that may put people at higher risk of acquiring the resistant strain.