In the Literature

Xiaoli L, James AE, Stahl AL, et al. Genetically similar high-risk strains of carbapenemase-producing Enterobacterales in humans and companion animals, United States. Emerg Infect Dis. 2026;32(3):341-348. doi:10.3201/eid3203.251458

The Research …

Carbapenemase-producing carbapenem-resistant Enterobacterales (CP-CRE) carry resistance mechanisms against critically important antimicrobials, including carbapenems, and are a major concern in human medicine. Although carbapenems are rarely used in companion animal medicine, emergence of CP-CRE in animals has become an increasing One Health concern.

In this study, researchers queried the National Center for Biotechnology Information Pathogen Detection database to identify One Health clusters of CP-CRE isolates from companion animals and humans in the United States, subsequently identifying genetically similar high-risk CP-CRE strains. Some isolates from companion animals belonged to globally disseminated human-associated clones, supporting the possibility of transmission among humans, animals, and shared environments. These findings reinforce growing evidence that companion animals may act as reservoirs or recipients of clinically important multidrug-resistant bacteria.

This study also highlighted how antimicrobial resistance is no longer restricted to referral hospitals or human health care settings. Notably, 75% of the animal CP-CRE isolates were identified through colonization screening, suggesting that companion animals may carry these organisms without clinical signs.

Although carbapenem use remains uncommon in companion animal medicine, recognition of CP-CRE highlights the importance of antimicrobial stewardship, appropriate diagnostic testing, and early suspicion of multidrug-resistant infections in everyday clinical practice.

… The Takeaways

Key pearls to put into practice:

• Culture and susceptibility testing should be strongly considered to guide treatment, particularly in recurrent, nonhealing, postoperative, health care–associated, and/or multidrug-resistant infections.¹ Empirical escalation to broader-spectrum antimicrobials (eg, fluoroquinolones, third-generation cephalosporins) without diagnostic confirmation should be avoided whenever possible.

• CP-CRE colonization may occur without clinical signs. In this study, identification of most animal CP-CRE isolates via colonization screening highlighted that clinically healthy animals may carry these organisms and potentially facilitate unnoticed dissemination among veterinary patients, veterinary team members, pet owners, and shared environments.

• Standard infection prevention and control measures (eg, hand hygiene, environmental disinfection, appropriate handling of hospitalized patients, barrier precautions when indicated) remain essential in general practice settings to limit transmission between patients and veterinary team members and should not be reserved exclusively for referral hospitals.²

• Detection of a multidrug-resistant organism should not automatically lead to alarm or stigmatization of the patient. Pet owner education should focus on practical hygiene measures, wound management, medication compliance, and minimizing exposure of immunocompromised individuals when appropriate.³

• Antimicrobial stewardship is a core component of modern companion animal practice. Even when carbapenems are not used, prescribing decisions involving other antimicrobial classes can contribute to broader resistance selection pressures across shared human–animal environments.¹