Raw feeding increases risk of resistant bacteria in dogs

Recent scientific evidence shows that raw feeding in dogs is associated with an increased risk of transmitting antimicrobial-resistant bacteria, such as Salmonella and Listeria. This scenario demands greater attention from veterinarians and owners regarding food safety and household biosecurity. The rise of raw diets for dogs, especially in the United Kingdom and Europe, has raised concerns about potential impacts on animal, human, and environmental health.

Raw feeding, based on uncooked meat and slaughterhouse by-products, has gained popularity among owners seeking alternatives considered more natural for their dogs. However, this trend raises concerns about the presence of zoonotic pathogens and the risk of spreading antibiotic-resistant bacteria. According to Furtado and colleagues, both veterinarians and owners recognize the potential microbiological risk of these diets but tend to consider it less important than other factors, such as nutrition.

Monitoring conducted in the United Kingdom between 2013 and 2022 identified an increase in the presence and diversity of Salmonella in raw dog foods. The number of Salmonella isolates in raw foods rose from 4 in 2013 to 606 in 2022, covering 39 different serovars. Between 2021 and 2022, there was significant overlap between the most common serovars in raw foods and clinical samples from dogs, including S. Typhimurium, monophasic S. Typhimurium, and S. Infantis, all relevant to public health. Regarding resistance, 9.9% of S. Infantis isolates from raw foods showed resistance to ciprofloxacin, and one case of S. Kentucky resistant to cefotaxime, ceftazidime, and ciprofloxacin was detected in a dog, according to Snow and colleagues.

Another study reported a salmonellosis outbreak in a Rottweiler kennel in Bulgaria, linked to the consumption of raw meat from an unlicensed source. All affected dogs showed clinical signs of infection and fecal shedding of Salmonella Agona, which was resistant to cephalexin, aminoglycosides, lincosamides, macrolides, and fusidic acid. After suspending the raw diet and adopting biosecurity measures, the outbreak was controlled, highlighting the importance of source control and hygiene in raw feeding, as noted by Boneva-Marutsova and colleagues.

The concern is not limited to Salmonella. A genomic analysis identified a multidrug-resistant strain of Listeria monocytogenes (BF11) isolated from raw pet food. This strain, in addition to carrying multiple resistance genes, shows high virulence and the potential to invade human cells, representing a public health threat and possibly escaping traditional surveillance systems, according to Mataragka and collaborators.

Beyond bacteria, the inclusion of slaughterhouse by-products in raw diets can facilitate the transmission of zoonotic parasites. In a survey conducted in Sardinian slaughterhouses, 67.7% of sheep had Echinococcus granulosus, with other parasites such as Cysticercus tenuicollis (2.4%) and Dicrocoelium dendriticum (14.7%) also identified. In cattle, the parasite load was lower but still relevant. Ahmed and colleagues emphasize that the high prevalence of these parasites reinforces the need for strict sanitary controls and decontamination measures before using these by-products in raw diets, especially in endemic regions.

Despite the evidence, there are differences in risk perception. Furtado and colleagues observed that veterinarians tend to value the dangers related to antimicrobial resistance more than owners, who trust in dogs' immunity and in their own food preparation processes. Professionals highlight that the introduction of resistant bacteria can occur at various stages of the production chain, while owners minimize these risks. This difference in perception hinders communication and the adoption of safe practices.

The reviewed studies have limitations, such as the difficulty of establishing direct transmission routes between raw food and infection in dogs or humans. Most data are based on passive surveillance and outbreak reports, which may underestimate the true prevalence of pathogens. In addition, broad-spectrum antibiotic resistance is still considered rare in these contexts, although the emergence of multidrug-resistant strains remains a concern.

In practice, the findings reinforce the need for active veterinary guidance on the risks of raw feeding, with emphasis on biosecurity, traceability of food sources, hygiene in preparation, and monitoring of animal and human health. Increased sanitary surveillance and the adoption of decontamination measures are recommended, especially in areas with high parasite prevalence or a history of bacterial outbreaks. Clear communication between veterinarians and owners is essential to balance nutritional benefits and health risks of this feeding practice.

In summary, although raw feeding in dogs continues to rise, scientific evidence points to concrete risks of pathogen transmission and antimicrobial resistance, requiring an integrated One Health approach and greater rigor in biosecurity practices and owner education.