Human Cases of Carbapenemase-Producing Escherichia coli Linked to Spread Between Animals and the Environment in a Veterinary Facility-Massachusetts, USA, 2023.

backgroundCarbapenemase-producing Enterobacterales (CPE), traditionally thought to cause hospital-acquired infection in humans, are now emerging as agents of both community-acquired infections in humans as well as hospital-acquired infections in pets. It is currently unknown what impact this spread among animals may have on human health.

methodsThe Massachusetts State Public Health Laboratory investigated links between 3 genetically related human cases of blaNDM-5-harboring Escherichia coli. Simultaneously, a separate, collaborative investigation into blaNDM-5-harboring E. coli animal infections at a Massachusetts veterinary hospital was conducted including animal and environmental screening. Whole-genome sequencing was performed on human, animal, and veterinary hospital environmental isolates. Once a genetic link was established between animal and human isolates, follow-up interviews including questions related to pet exposure were performed with affected humans.

resultsWhole-genome sequencing demonstrated that human, animal, and veterinary environmental isolates clustered within 0-10 single nucleotide polymorphisms. Although initial case interviews failed to identify any epidemiologic linkages between the humans, follow-up questioning revealed that all 3 human cases had pets treated at the same veterinary hospital prior to their diagnosis.

conclusionsThis report suggests the potential for transmission of blaNDM-5-harboring E. coli between animals and people. There is an urgent need to invest resources and develop a One Health approach to support veterinary facilities in recognizing and preventing transmission of CPE to limit spread within communities. Physicians, veterinarians, and public health professionals conducting outbreak investigations should be aware of this potential route of CPE spread.