First Report of Multidrug-Resistant Carbapenemase-Producing Bacteria Coharboring mcr-9 Associated with Respiratory Disease Complex in Pets: Potential of Animal-Human Transmission

Carbapenem and colistin antibiotics have been classified as critically important antimicrobial agents and are reserved primarily for the treatment of severe infection caused by multidrug-resistant bacteria (1–3). Colistin was frequently used for decades to treat and prevent infectious diseases in animals (4, 5). In contrast, carbapenem was prohibited for use in veterinary medicine in the United States based on the Animal Medicinal Drug Use Clarification Act of 1994, as well as similar rules in other countries, including members of the European Union (EU) and Australia (1). This is the first report to confirm the coproduction of MCR-9 and VIM-4 from animals, the first identification of OXA-244 from animals, and the first report to confirm their potential animal-human transmission.