A new study has found that feeding dogs uncooked meat increases their risk of excreting E. coli that is resistant to a widely-used antibiotic, thereby increasing the potential that the bacteria will be passed on to owners and other people and cause infections that may be difficult to treat.

The main cause of antibiotic resistance is antibiotic overuse. The more we use antibiotics, the more opportunities bacteria have to become resistant to them. Fluoroquinolones are a class of broad-spectrum antibiotics that are used in both human and veterinary medicine. However, their widespread use has driven up resistance rates, prompting attempts to reduce the use of fluoroquinolones in many settings.

Now, a new study by researchers at the University of Bristol in the UK has found that feeding dogs uncooked meat increases their risk of excreting E. coli bacteria that are resistant to ciprofloxacin, a widely used fluoroquinolone antibiotic.

“Our aim was not to focus on raw dog food, but to investigate what might make a dog more likely to excrete resistant E. coli in its feces,” said Jordan Sealey, lead author of the study. “Our study found a very strong association between excreting ciprofloxacin-resistant E. coli and feeding dogs a raw food diet.”

E. coli are found in the intestines of people and animals, and can be passed between them, usually due to poor hygiene or handling food contaminated with fecal material, including uncooked meat. The bacteria can cause diarrhea and food poisoning or more serious illnesses like urinary and bloodstream infections in humans and can sit in the intestines for years without causing an infection.

The researchers recruited 600 healthy adult dogs and collected their fecal samples. Each sample was tested to see if the E. coli present were resistant to ciprofloxacin. In addition, the dogs’ owners completed a survey that provided details about their dogs, their diet, the environments the dogs walked in and whether the dogs had been treated with antibiotics.

Ciprofloxacin-resistant E. coli were detected in the feces of 7.3% of rural dogs and 11.8% of urban dogs. Analysis of those dogs’ samples showed that feeding them uncooked meat was strongly associated with the excretion of antibiotic-resistant bacteria, which, the researchers say, could serve as a transmission link for resistant E. coli entering the home.

“Raw meat – whether intended for human consumption after cooking or sold as raw dog food – is likely to be contaminated with antibiotic-resistant E. coli,” said Matthew Avison, the study’s corresponding author. “Cooking kills the bacteria, and good hand hygiene reduces the immediate risk of these bacteria being swallowed and getting into a person’s intestines.”

The researchers say it’s not just a dog’s feces that poses a risk but also the handling of raw meat when preparing a pet’s meal.

“Choosing to feed a dog raw meat means a person almost certainly has to handle the raw meat, and our research is clear that raw feeding also means pet owners are likely to be interacting with a pet that is excreting E. coli,” Avison said.

They offer some suggestions to avoid contamination with the bacteria.

“Individual measures to reduce the risk of resistant bacteria being excreted by dogs include changing to a non-raw food diet or sourcing good quality raw meat that can be cooked, and then cooking it,” said Sealey. “Most raw food sold for consumption by dogs is not of a quality that can be cooked, and can cause a serious health hazard to dogs if cooked.”

This is in keeping with American Veterinary Medical Association (AVMA) policy, which discourages feeding dogs and cats “any animal-source protein that has not first been subjected to a process to eliminate pathogens because of the risk of illness to cats and dogs as well as humans.”

In determining whether to feed your pet raw meat, it’s important to consider the source. Abattoirs slaughter animals for human-grade meat, whereas knackeries produce pet-grade meat, which may come from dead, diseased, dying or disabled animals.

“As part of our response to the emerging crisis of antibiotic resistance, further incentive should be given to companies joining the raw dog food industry to source meat from farms with appropriate antibiotic usage policies and to test meat for resistant bacteria before selling,” Avison said. “Stricter limits should be set on the numbers of bacteria allowed in meat that is sold to be eaten uncooked than in meat sold to be cooked prior to eating.”

The study was published in the journal One Health.

Source: University of Bristol