Raw dog food contaminated with resistant bacteria

New studies on dog food sold throughout Europe have revealed the presence of antibiotic-resistant bacteria in raw products, including superbugs found in hospitalized patients. The current trend of feeding dogs raw food could therefore contribute to the spread of multidrug resistance and become a major source of antimicrobial resistance, posing a risk to global public health.   Every year, 700,000 people worldwide die from infections caused by resistant bacteria. Although there are many drugs capable of fighting bacteria, the bacteria have evolved in response to them and developed defense mechanisms that allow them to evade the drugs’ effects. The overuse and misuse of antibiotics in recent years have only exacerbated this problem and encouraged the spread of these multidrug-resistant bacterial strains. This has become a major issue in human and animal health. If no action is taken, some 10 million lives will be put at risk annually by resistant bacteria by 2050. The World Health Organization (WHO) classifies antibiotic resistance as one of the greatest threats to public health worldwide.   Preserving the effectiveness of antibiotics is therefore a real challenge that requires an integrated approach. All sources and factors must be taken into account to prevent the development of antibiotic resistance. Portuguese researchers have therefore focused on pet food as a potential source of the spread of resistant bacteria. They analyzed dog food sold in supermarkets and pet shops to identify the presence of enterococci. These opportunistic bacteria generally live in symbiosis in the human and animal intestines, but in some cases can cause serious infections if they spread to other parts of the body. In total, of the 55 foods from 25 different brands analyzed (22 wet, 8 dry, 4 semi-moist, 7 treats, and 14 raw-frozen), 54% contained enterococci. The most concerning finding for the researchers was that more than 40% of the enterococci detected showed antibiotic resistance (erythromycin, tetracycline, quinupristine-dalfopristin, streptomycin, gentamicin, chloramphenicol, ampicillin, or ciprofloxacin), and 23% were also resistant to linezolid, a last-resort antibiotic used to treat severe infections when all other medications have failed, and which is considered a critically important antibiotic by the WHO.   The most heavily contaminated products were raw dog foods, all of which contained multidrug-resistant enterococci, including resistant bacteria to linezolid, whereas only three samples of non-raw dog food were contaminated with multidrug-resistant bacteria. Researchers are concerned about the danger these bacteria pose and their potential transmission to humans. They demonstrated that the multidrug-resistant bacteria found in raw dog food were genetically identical to those isolated from farm animals and wastewater, but especially from hospitalized patients in the United Kingdom, Germany, and the Netherlands. These resistance genes can be transferred to other bacteria. The researchers conclude that raw dog food is an overlooked source of the spread of bacteria with antibiotic resistance—particularly those of critical importance—which could potentially affect human health. The trend toward feeding dogs raw food would thus contribute to the global spread of antimicrobial resistance. Close contact between owners and their dogs fed contaminated products also poses a significant public health risk on a global scale. It is up to European authorities to raise awareness about the risks of raw feeding and to review quality control and hygiene practices regarding ingredient selection and the storage of dog food. In the meantime, researchers recommend that animal owners always wash their hands after handling pet food or picking up feces.