Scientists have found drug-resistant superbugs harmful to humans in two raw dog food brands, sparking a new debate about the safety of increasingly popular diets.
The research, which was conducted in Portugal and presented this month at the European Conference on Clinical Microbiology and Infectious Diseases, is increasing pressure on governments to regulate the production of raw pet food more tightly.
At least one researcher suggests that veterinarians, too, consider warning clients of the dangers of superbugs if they haven’t already.
Antimicrobial resistance, or AMR, occurs when disease-causing microbes evolve to avoid drugs that are intended to kill them, a process that can be speeded up by drug overuse. Many scientists consider antimicrobial resistance to be one of the greatest threats to humanity, along with climate change and nuclear war.
To combat drug resistance, regulators around the world have for years discouraged doctors from prescribing antibiotics and other antimicrobial drugs. Recently, the agricultural sector has been urged and forced to limit the use of antimicrobials in animals raised for food. Less attention has been paid to addressing the direct infection risks posed by pet food.
Raw food is of particular concern because many pathogens die when cooked at high enough temperatures, although cooked food, too, can become contaminated.
Scientists at the University of Porto tested 55 samples of dog food, 14 of which were frozen raw, for bacteria Enterococci, which can cause urinary tract infections, blood infections, and meningitis, among other conditions. The samples were taken from different types of dog food – frozen raw, wet, dry, semi-moist and processed – collected from nine retail stores in northern Portugal. The samples included 25 brands that the researchers did not mention. Twenty-one brands are sold in multiple countries, including the raw brands.
The researchers were alarmed by the results. Thirty of 55 samples were contained enterococci, And 26 isolates were resistant to at least one antibiotic. Enterococci It found in all 14 raw frozen samples resistance to three or more different families of antimicrobials—in other words, it was multidrug resistant. By comparison, multidrug-resistant isolates were found in three samples of cooked produce: two wet foods and one treat.
“These bacteria can be transmitted to humans by direct contact with dogs, their food or their faeces,” said Anna Freitas, a molecular geneticist at the University of Porto who led the research.
Drug-resistant pathogens can instantly sicken victims or establish themselves more subtly in the digestive tracts of pets and their owners.
“People can have a gut reservoir of resistant bacteria that might swell in opportunistic situations, like hospital antibiotic treatment,” Freitas said.
Drug resistance of last resort is of particular concern
The Enterococci In the samples it tolerated a variety of antibiotics, including erythromycin, tetracycline, ampicillin and ciprofloxacin, among others. The researchers were particularly concerned about the level of resistance they found to linezolid, which the World Health Organization has classified as being of critical importance in human medicine because it is usually effective against drug-resistant bacteria. Among the 55 samples, seven were found to contain linezolid مقاومة resistance EnterococciAll are raw.
“These results were surprising because the solid linear resistance rates are still generally low, according to the available data,” Freitas said. “The hidden spread of those resistant enterococcal isolates could increase them in the clinical setting, with consequent increase in morbidity and mortality from enterococcal infection.”
Another scientist said the research findings, while providing an important reminder of the dangers of antimicrobial resistance, are not groundbreaking in a historical context. The result ‘may be of less concern than a different one [other] “For the past 10 to 15 years,” said Dr. Scott Weiss, an infectious disease expert at the Ontario Veterinary College at the University of Guelph in Canada.
Weese, who in 2019 blogging about Antimicrobial resistance in raw pet food, showing those Gram-positive bacteria, such as enterococci, Less important than the gram-negative species. Gram-negative bacteria have a stiffer cell wall that can make killing them more difficult. Their presence has been identified in previous studies, including research Published in 2008 by Weese and colleagues who found that dogs who ate raw meat were 15 times more likely to pass their cephalosporin-resistant faeces Escherichia coli. Recently, research has been conducted in United kingdom And Holland Also identified high levels of drug resistance coli bacteria In pets on a raw diet compared to those on cooked meals.
Researchers in Portugal acknowledge previous findings, but say investigations into antimicrobial resistance in pet food are still relatively rare, especially for Gram-positive bacteria such as gut colonizers. Enterococci. They note that Linezolid-resistant insects have only recently been observed in domestic animals.
Drug resistance aside, the findings in Portugal add to existing concerns about general infection and other safety risks posed by uncooked food. Raw meat has been marketed as healthy for pets because it is similar to the diets of animals in the wild, and it has been involved in several pet food recalls recently around the world.
In a recent incident, at least 10 dogs in the Australian state of Victoria He died after eating raw food produced in the Mafra Knackery region. The slaughterhouse issued a summons on July 20, but the incident nonetheless sparked requests to toughen regulations for the pet food market in Australia, where recalls are voluntary. All the dogs died of liver failure caused by the toxic plant endosperin suspect investigators They were swallowed by animals before they were slaughtered. (However, cooking may not degrade endosperin.)
Other recent incidents include a I remember in 2019 of raw pet food sold by Natural Instinct in the UK is suspected of causing an outbreak of feline tuberculosis that has killed at least five cats. In a separate incident, this month Natural Instinct recalled raw duck food to contain salmonella. In the US last November, Albright recalled products containing raw chicken because they “could” be contaminated with salmonella.
In a study published in 2014, U.S. Food and Drug Administration researchers and collaborators found that raw pet food is more likely to be contaminated with pathogens than dry pet food. Agency summarizes the results under a Publishing on the web Unambiguously titled in part: “Raw pet diets can be dangerous to you and your pet.”
Are the purported benefits of raw food worth the risk?
According to research Published in 2019. Separate Research published last year, based on responses from 3,673 pet owners in Australia, Canada, New Zealand, the United Kingdom and the United States, indicated that 9% of dogs and 6% of cat owners fed their pets exclusively raw food; and 66% and 53%, respectively, a diet that included raw food. The researchers compared these results to nine peer-reviewed articles published over the past 10 years and found that feeding non-traditional diets — such as raw, local and plant-based diets — is becoming more prevalent.
There is little scientific research on the nutritional benefits of raw pet foods. “The idea is that animals have shinier coats, cleaner teeth, find them more palatable, and because they are more digestible, they have smaller stools,” said Dr. Scott Campbell, a veterinarian based in Ipswich, Australia. “I think there is an element of truth in all of that.”
Meanwhile, Campbell — who is also a clinical nutrition consultant for the Veterinary Information Network, an online community for the profession and father of the VIN news service — said the dangers of raw dog food are well known. Aside from the risk of infectious diseases, he said, dogs may suffer from nutritional imbalances. Campbell also said he regularly sees dogs, usually dogs, that have broken teeth because they were bitten on the bone. Some animals also develop gastrointestinal obstruction caused by bones in raw food.
Furthermore, Campbell notes that the ancestors of non-vaccinated dogs tended to live for only five or six years in the wild and may have killed much smaller prey and eaten it fresh, rather than for example cattle or sheep weeks after their slaughter.
Dr. Susan G. Win, chief scientific officer for raw food producer Instinct Pet Food, agreed that few, if any, studies have confirmed that raw food offers nutritional benefits, but said evidence is mounting that it does. For example, Wynn cited work in progress at the University of Helsinki called the DogRisk study, which indicated that feeding pets raw food reduces the likelihood of infection. skin disease and inflammatory bowel disease. She pointed to other studies that found dogs fed raw food were less likely to be infected with roundworms or to become obese.
Wayne, a veterinary dietician and alternative medicine consultant at VIN, personally suspects that raw food retains nutritional complexity because hundreds of compounds can be lost during cooking, a process that can contaminate the food itself. “The fact that the use of raw pet food has grown worldwide despite active opposition from government officials and professionals suggests that something good is happening for many pet owners,” she said.
Of course, not all raw food companies are created equal. “Forging a complete, balanced diet with raw ingredients is easy to do,” said Wayne, an advocate of minimal processing. “It is not easy to ensure that the final product is complete and balanced, which is something that all home-made raw nutrients ignore, and many commercial pet food companies fail to do so either.”
Campbell, for his part, is asking customers to be careful. “I’m hesitant to say commercial food is better, but it’s easier to get food right, especially for people who lead busy lives with regular pets,” he said. “When the owners want to do that, you can give them some guidance on grinding the bones and trying to achieve nutritional balance.”
When it comes to drug resistance, Wayne said there are various ways producers can mitigate the risks, such as applying high-pressure processing or adding probiotics to suppress the growth of bacterial pathogens in meat. Freitas of the University of Porto said regulators could at least play their part by enforcing high standards for raw material selection, food manufacturing, hygiene and disease screening practices.
Consumers who choose raw foods can also contribute. “Dog owners should wash their hands with soap and water immediately after coming into contact with animal feed or droppings,” Freitas said. “This is just a drop in a large ocean contributing to the global antimicrobial resistance crisis, but it could help us better contain it.”