Early detection prevented worse outcomes in Calgary E. coli outbreak at 11 daycares: study

A standardized public health response to an E. coli outbreak at several Calgary daycare centres three years ago resulted in fewer children developing serious health complications, a new study suggests.

The study, conducted by researchers at the University of Calgary and published in the medical journal JAMA Network Open Tuesday, found that early detection methods used by doctors at the Alberta Children’s Hospital helped mitigate the worst potential outcomes of the outbreak.

“We have reason to believe that our standardized care and the implementation of the pathway and intensive monitoring resulted in the prevention of fatalities,” said Dr. Mohamed Eltorki, the study’s lead author.

Alberta Health Services declared an E. coli outbreak in September 2023 after it said contaminated food from a central kitchen was distributed to several daycare locations run by Fueling Minds Inc. According to the study, 448 people — mostly children — fell ill, with the most serious cases involving 21 patients who were diagnosed with hemolytic uremic syndrome (HUS).

Eleven daycares were affected by the outbreak, the study said. An AHS report the following year listed contaminated meatloaf as the likely cause of the outbreak. 

The goal was to expand on the AHS report, the study said, and quantify the health-care system’s response.

The retrospective analysis looked at all the confirmed cases of E. coli among children and adults who either became sick after ingesting the contaminated food item or became infected through contact with a sick person.

The analysis also documented the process health care professionals used to detect E. coli — particularly the O157 strain, which produces the shiga toxin — and the steps taken to treat those who were infected. 

Eltorki said the shiga toxin is particularly dangerous because it causes HUS, which can lead to kidney failure. According to the study, 15 to 20 per cent of children who contract E. coli carrying the shiga toxin develop HUS.

“We don’t know specifically why, but there is a theory that [children] have more receptors for the toxin,” said Eltorki, who is also a pediatric emergency medicine specialist at the Alberta Children’s Hospital.

Historically, families would be told to monitor symptoms from home and return to the emergency department if symptoms such as tea-coloured urine or seizures occured, Eltorki said.

Similarly-sized outbreaks in the past have almost always resulted in fatalities, he added, but years of research means Alberta has developed protocols for emergency infections alongside mandatory and frequent testing to detect the bacteria before severe symptoms appear.

“We took a proactive way of handling the infection,” Eltorki said. “We’ve had a clinical pathway for E. coli infections that we’ve implemented in Alberta in the last 10 years or so.”

Dr. Stephen Freedman, a senior investigator on the study and professor of pediatrics and emergency medicine at the Cumming School of Medicine, said cases of E. coli are fairly common in Alberta due to the large number of cattle in the province.

Typically, however, there are only a few minor cases among children in the summer, Freedman said.

“This was an unprecedented outbreak,” he said. “All of a sudden, in the fall of 2023 we saw a massive surge in the number of children with this infection.”

Freedman said because the scale of the outbreak was so large, it provided an opportunity to share how a standardized early-detection response can work, and its effectiveness.

“We believe our research is setting the standard,” he said.

“That’s what made it so important that we actually share our knowledge of what we did, what we experienced, how we managed this outbreak and how we actually believe that our approach to management improved outcomes.”