Coloradan who died from an E. coli infection linked to McDonald's food was a Mesa County resident

Updated: 4:02 p.m

An outbreak of E. coli believed to be linked to McDonald's Quarter Pounders has been particularly felt in western Colorado, where more than a dozen residents have become ill and one person has died.

In a news release Wednesday and a subsequent interview, Mesa County Public Health noted that at least 10 of the state's 26 confirmed cases of E. coli were in Mesa County, including the country's only death. The county is still waiting for laboratory genomic results from several other sick people to confirm whether they also have E. coli in their bodies.

The state health department suspects that all McDonald's locations in the state of Colorado received ingredients from the same suppliers and therefore assumes that all of the chain's locations in the state could be affected.

The confirmed Colorado cases so far come from nine counties across the state: Arapahoe, Chaffee, El Paso, Gunnison, Larimer, Mesa, Routt, Teller and Weld. The agency said the infected people may not have eaten at a McDonald's location in the county where they live and expects the numbers to change as additional cases are investigated.

Federal health data shows the first case linked to the outbreak was recorded on Sept. 27 and no new cases have been confirmed since Oct. 11.

“The person who died was an older adult,” said Dr. Rachel Herlihy, the state epidemiologist. “We know that older adults and young children are most susceptible to severe disease with this type of E. coli infection and are more likely to develop complications of the infection.”

She said the eight hospitalizations involved a wide range of ages, “but we were fortunate that we had no cases in young children in the state.”

She said the most recent cases occurred in teenage children: “But we know that the youngest children are the most vulnerable to severe outcomes. “It's definitely a good thing we didn't see that.”

She said the health department began investigating when it noticed E. coli cases were emerging above the usual baseline and began investigating, including interviewing people who reported similar symptoms.

“We conduct patient interviews to find out what foods patients may have eaten before becoming ill,” she said. Investigators will ask questions about what foods were involved, when they ate them and where they ate them “to get a sense of whether there are possible connections between these cases.”

Then the agency pairs that data with laboratory data, whole-genome sequencing data or genetic fingerprinting data, which can give it even more information and tell investigators whether “these bacteria are genetically related to each other in a way that will help us better understand.” “To create a picture of a potential outbreak,” she said.

The outbreak was first reported Tuesday and is believed to be related to onions served on the Quarter Pounder, Mesa County officials said in the news release, citing the Food and Drug Administration. However, investigators are still looking into the possibility that the beef patties were contaminated.

“While the specific source of contamination remains under investigation, initial information from the Food and Drug Administration indicates that the onions on McDonald's Quarter Pounders may be a cause of this outbreak. Fresh-cut onions are used primarily for Quarter Pounder hamburgers and not for other menu items,” Erin Minnerath, deputy director of Mesa County Public Health, said in the news release. “The USDA is also investigating the beef patties on the Quarter Pounder hamburgers.”

Mesa County Public Health is conducting interviews with residents to further trace the source of the infection.

“We have local experts with an efficient system to deal with these situations. This helps to speed up the investigation and prevent more people from becoming ill,” said Minnerath.

E. coli is a bacterium that occurs in many places in nature, particularly in the intestinal bacteria of animals and humans. There are many different varieties, many of which are not harmful, some are even theorized to be potentially beneficial to normal intestinal flora.

“However, there are certain strains of E coli that are particularly pathogenic or likely to cause disease. And that's exactly what we're seeing here with this outbreak at McDonald's,” said Dr. Daniel Pastula, professor of neurology, infectious diseases and epidemiology at the University of Colorado School of Medicine and the Colorado School of Public Health. “This has been shown to be pathogenic or disease-causing in the past.”

He said infections could prove serious in some cases, particularly in children under five, people over 65 and people with weakened immune systems. It can cause gastroenteritis, nausea, vomiting and diarrhea.

“This is not the type of E. coli you want to introduce into your body,” he said.

The bacteria produce toxins that can sneak into your intestinal tract. In severe cases, that can lead to bleeding and bloody stools, he said. In addition, severe dehydration can occur due to fluid loss through diarrhea and vomiting. Sometimes a person is hospitalized with serious symptoms, and although this type of infection is rare, it can lead to kidney failure.

“We think it's caused by these toxins triggering a large inflammatory cascade in the smallest blood vessels and leading to the formation of small blood clots. “So in some cases this can be quite serious,” he said.

The strain is often transmitted through food, which is why Pastula says it's important to cook meat at a high enough temperature, avoid cross-contamination of food during food preparation, avoid unpasteurized dairy products, wash hands and clean surfaces.

All of the people interviewed by investigators said they had eaten at McDonald's before the onset of their illness, specifically eating a Quarter Pounder.

McDonald's told the CDC that they have proactively removed the onion slices and beef patties used in the Quarter Pounder hamburgers from stores in states where cases have been reported while the investigation continues. Quarter Pounder hamburgers may be temporarily unavailable in some states, the agency said.

According to the Cleveland Clinic, most strains of E. coli spread through fecal-oral transmission.

“This happens when bacteria from feces that are too small to see enter the mouth and digestive tract,” the website says. Some forms can also be transmitted through undercooked meat and unpasteurized beverages.

It lists the possible ways to become infected with E. coli through contaminated food, drinking unpasteurized beverages, driving or having contaminated water in your mouth, touching feces or contaminated surfaces, and improperly wiping after using the bathroom.

“What you're seeing with the contaminated ground beef or cross-contamination with vegetables or whatever is there is potentially small pieces of feces at a microscopic level” getting into the food, Pastula said.

He said pinpointing the source of contamination often requires a complex investigation by local and state health officials working with the CDC.

“It just shows how important a robust public health response system is, because these types of outbreaks will never completely go away,” Pastula said. “We need to be able to respond quickly and prevent future cases as much as possible.”

This is a developing story and may be updated.