Bacteria from meat may cause more than a half-million UTIs, study says

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For those wondering how they are getting urinary tract infections despite taking care of their hygiene and urinating after sex — two known ways to avoid the risk of UTIs — a new study suggests that bacteria from meat may be responsible.

E. coli bacteria from meat is likely to cause hundreds of thousands of urinary tract infections in the United States each year, says a George Washington University study published Thursday.

Eighty-five percent of UTIs are caused by E. coli, and 8 percent of these infections are acquired from meat, according to the research.

The study, published in the journal One Health, looked at 1,188 samples of E. coli from humans and 1,923 samples from meat, including chicken, turkey and pork, in Flagstaff, Ariz., and estimated, for the first time, that foodborne E. coli strains may be causing as many as 640,000 UTIs each year.

"Most people understand that eating uncooked meat, or accidentally ingesting bacteria from meat, can cause you to have an upset stomach," said Lance B. Price, a professor of environmental and occupational health at GWU and one of the scientists leading the study. "But now we also know that specific varieties of E. coli, coming from raw meat, are also causing hundreds of thousands of UTIs."

Price said the study has expanded the understanding of what a food-borne infection can look like and how it can be prevented.

The team of scientists, which included Cindy Liu from the GWU Milken Institute School of Public Health, used a genomic approach to track the origins of E. coli infections.

"E. coli bacteria adapts to its host, so each sample of bacteria we found had its own packet of DNA," Price said. "We then developed a statistical model which analyzed all that DNA and predicted whether that bacteria came from an animal, and if so, which animal."

UTIs are extremely common in the United States; about 6 million to 8 million people get them annually.

Women are at highest risk of contracting UTIs because of their anatomies, Price said. Children and older people also are at higher risk than other groups for reasons including the use of diapers, incontinence or limited access to bathrooms, he said.

UTIs can be potentially life-threating in older people, said Christine Kistler, associate professor in geriatric medicine at the University of North Carolina, who researches UTIs in the elderly.

"Most UTIs are caused by E. coli, if you wipe the wrong way, for example, or don't empty your bladder often enough," said Kistler, who was not involved in the study. "But the link to food is very interesting. If you have E. coli caused by food contamination, it usually shows up in the gut."

She pointed out, however, that older people often have bacteria present in their bladders that don't produce problems and should never be treated. "We massively overtreat UTIs in older people," she said. "We should only treat actual infections, meaning those that cause symptoms."

UTIs most commonly result in bladder infections, which are recognizable through pain or a burning sensation while urinating, frequent urination, blood in the urine, or cramps in the groin or lower abdomen, says the Centers for Disease Control and Prevention.

Some UTIs also can lead to more serious kidney infections; symptoms include fever, chills, back pain, and nausea or vomiting, or life-threatening blood infections, according to the CDC.

"Blood stream infections with E. coli kill 36,000 to 40,000 people a year in the United States," Price said. "Reducing the number of infections spreading through E. coli that comes from meat will be a big contribution."

How bacteria reach your urinary tract

Data from the Food and Drug Administration suggests that most raw meat products are contaminated with E. coli., and the GWU study found that 81.7 percent of the 2,460 meat products they tested carried E. coli.

E. coli can live in people and food animals. When animals are slaughtered, the bacteria living inside them can contaminate meat products and cause infections if the meat is ingested by humans.

Before they find a chance to travel from the gastrointestinal tract to the urinary tract and trigger infections, E. coli bacteria that cause UTIs can live in the gut for a while, earning them the title of "opportunistic pathogens."

"It can a be a long time between your exposure to the meat and the time that you actually got the urinary tract infection," Price said.

Experts have long suspected that food-borne pathogens become part of our microbiome, and this "very nice study" suggests they "survive the acid of our stomach and digestive process," and do take up residence there, said William Schaffner, professor of preventive medicine in health policy and professor of medicine in the division of infectious diseases at Vanderbilt University Medical Center.

"Then something happens, often anatomically, that causes them to get into the bladder, causing a UTI, or the bloodstream, causing sepsis," said Schaffner, who was not involved in the study.

Could animal vaccines prevent food-borne UTIs?

Earlier messaging was that E. coli infections could be prevented by ensuring that meat was well-cooked, avoiding cross contamination, which includes washing hands and the cutting board after handling meat, and minimizing exposure to raw meat.

Infectious-disease specialists also have repeatedly warned of the dangers of indiscriminate use of antibiotics in food animals, a practice that contributes to the development of bacterial strains that do not respond to traditional treatments.

"These findings illustrate the connections between animals in the food supply and humans, and underscores the importance of avoiding unnecessary antibiotic use in animals, which will lead to drug resistant bacteria that will find their way into humans," said Elizabeth Connick, professor of medicine and immunobiology and chief of the infectious diseases division at the University of Arizona, who was not involved in the study.

Understanding the new foodborne route of UTIs, on which the study focuses, also has opened the door for new interventions such as vaccinations.

"We have identified the really risky strains of E. coli in animals," Price said. "And now we can vaccinate them against these specific bacteria, resulting in a win-win for public health as well as the animal industry."

Vaccinating the animals against six of the most dangerous strains of bacteria will ensure that they do not enter the food supply.

Price said concerned citizens could call lawmakers in Congress to ask that the Department of Agriculture put more money toward food safety, including eliminating dangerous bacteria from food animals.

"We needed new ways to prevent these infections, and this is opening that door for us," he said. "This study puts even more responsibility on food and animal producers to prevent these bacteria from making their way into the food supply."

Marlene Cimons contributed to this report.