Investigation into multi-resistant salmonella outbreak suggests link to pet treats

A new study examining an outbreak of multidrug-resistant Salmonella infection in several U.S. states linked to pig ear treats highlights the link between human health and pet ownership and stresses the need for strict monitoring of pet food products.

The study was funded by the Food and Drug Administration’s Animal Feed Regulatory Program Standards and the FDA’s Veterinary Laboratory Investigation and Response Network (Vet-LIRN).

From June 2015 to September 2019, 154 cases of human Salmonella infections were reported in 34 states. The investigation identified seven Salmonella serotypes genetically related to samples from pig ear pet treats. Whole genome sequencing (WGS) of the isolates was used to predict antimicrobial resistance. Specifically, 107 of 122 patients surveyed reported contact with dogs, and 65 of 97 reported contact with pig ear pet treats. Salmonella was isolated from 137 pig ear treats, including imports from Argentina, Brazil, and Colombia, and from four dogs. WGS predicted that 77 percent of human isolates and 43 percent of pig ear treat isolates were resistant to three or more antimicrobial classes.

Investigation results

The study was published in the journal Lancet public healthis investigating the first documented multi-state outbreak linked to pig ear treats. The outbreak investigation involved multiple agencies, including the CDC, FDA, and state health departments, identifying the sources of the contaminated pig ear treats and evaluating their antimicrobial resistance profiles.

Pig ear treats and dog food have been tested for salmonella by government agencies and the FDA. The products were traced back to their country of origin where possible. Three pet food manufacturers had imported contaminated pig ear treats from South America, leading to nationwide recalls at six suppliers.

Impacts and consequences for public health

The outbreak involved 154 human cases, with 107 patients reporting contact with dogs. The investigation found that both direct contact with pig ear treats and zoonotic transmission from dogs contributed to the spread of Salmonella. The study highlights the risk posed by contaminated pet treats and the potential of these products to transmit antibiotic-resistant bacteria to humans.

Regulatory and preventive measures

Pet treats such as pig ears are regulated by the FDA under the Federal Food, Drug, and Cosmetic Act, which requires that all pet foods be safe, produced under sanitary conditions, and free of contaminants. However, the investigation found that efforts to reduce pathogens before and after processing were inadequate in this case.

The study also found that pig ear treats labeled as irradiated were still contaminated with Salmonella. Irradiation is a method used to reduce pathogen load without heating the product. The effectiveness of irradiation on treats made from dried animal byproducts, such as pig ear treats, has not been well studied.

recommendations

The investigation highlights the need for increased monitoring of internationally traded pet food products for foodborne pathogens. It also calls on international manufacturers to strengthen strategies to reduce product contamination. Pet owners should be aware of the disease risks associated with pig ear treats and take appropriate precautions, such as washing hands after handling pet food or treats.

The outbreak illustrates the widespread risk to pets and pet owners from contaminated pig ear treats. The study identified multiple Salmonella serotypes and antimicrobial resistance profiles and highlights the need for coordinated containment efforts between state and federal agencies.

This outbreak of multi-drug resistant Salmonella linked to pig ear treats highlights the links between human and animal health. It underscores the need for strict monitoring and regulation of pet food products to prevent future outbreaks. Consumers should be aware of the potential health risks and take steps to protect themselves and their pets.

Further information about this study and its results can be found here.

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