Study proposes US reporting framework for CROs in pets

Version 2

A new AJVR study puts structure around a problem many veterinarians already recognize: when a carbapenem-resistant organism is identified in a dog or cat, it’s often unclear who should be told, how quickly, and what should happen next. In A framework for reporting carbapenem-resistant organisms in companion animals in the United States, researchers surveyed US public health veterinary contacts and evaluated an interagency communication algorithm designed to improve reporting and follow-up for these high-concern resistant pathogens. The article appears in the July 14, 2026, issue of AJVR. (vetlit.org)

The need for that framework has been building for several years. Carbapenems are critically important drugs in human medicine, and although they are not approved for veterinary use, CDC notes they may be used rarely in dogs and cats in an extralabel manner. At the same time, CDC says CRE and carbapenemase-producing CRE can spread between animals, between animals and people, and through contaminated hands, equipment, and surfaces. That has made companion animal detections more than an isolated microbiology finding; they’re increasingly treated as a One Health signal with implications for infection prevention, stewardship, and public health response. (cdc.gov)

Earlier US work showed why communication has been such a weak point. A 2020 survey of veterinary diagnostic laboratories found that nearly all responding labs included at least one carbapenem on primary susceptibility panels, but only 39% performed phenotypic or molecular carbapenemase testing, and most were not aware of CRO reporting mandates. Just 35% said they would notify public health if a CRO was detected. In parallel, CDC-backed and academic groups have been piloting One Health reporting models, including a Kansas-Missouri effort that created surveillance and reporting protocols plus educational handouts for veterinarians and pet parents when CRE and other resistant organisms were identified. (pubmed.ncbi.nlm.nih.gov)

The epidemiology helps explain why the issue deserves attention even if case counts are still low. A 2024 nationwide study using IDEXX laboratory data found imipenem susceptibility of 98.86% among more than 477,000 Enterobacterales susceptibility tests from dogs and cats collected from 2019 through 2022, suggesting CRE remain uncommon overall. But the same study identified geographic clusters, including signals in Missouri, Florida, New York, Texas, and the West Coast, indicating that risk is not evenly distributed. Another US multicenter study screening fecal specimens from dogs and cats found confirmed carbapenemase-producing Enterobacterales in 5 isolates from 4 dogs and 1 cat, a prevalence of 0.21%, and reported that some animal isolates were closely related to previously characterized human isolates. (pubmed.ncbi.nlm.nih.gov)

Industry and public health commentary has been moving in the same direction as the new framework. CDC’s guidance for veterinarians says that if a clinic identifies an animal infected or colonized with CRE or CP-CRE, it should act quickly, follow standard precautions, notify the pet parent, review prior and subsequent cultures for additional cases, and contact public health or animal health officials. Recent publications have also described operational state-level models linking companion animal and human carbapenemase-producing Enterobacterales through whole-genome sequencing, as well as hospital-based surveillance programs that fold CRE into broader multidrug-resistant organism monitoring and infection control efforts. Taken together, that suggests the AJVR framework is arriving as the field shifts from awareness to system-building. (cdc.gov)

Why it matters: For veterinary professionals, standardized reporting is less about compliance for its own sake and more about what happens after the lab result. A clearer pathway can support confirmatory testing for carbapenemase production, help determine whether a case may be sporadic or part of facility-associated spread, and trigger practical steps around isolation, environmental cleaning, staff protection, antimicrobial stewardship, and pet parent counseling. It may also reduce the uncertainty that smaller practices and laboratories face when they encounter a rare CRO result and aren’t sure whether the right next call is to a state veterinarian, a public health veterinarian, a diagnostic laboratory, or all three. (pubmed.ncbi.nlm.nih.gov)

There’s also a broader strategic point for the profession. Companion animals have often been underrepresented in antimicrobial resistance surveillance compared with human healthcare and food animal systems, even though close household contact creates opportunities for bidirectional transmission. WOAH recently said AMR in companion animals is increasingly recognized as a threat to both animal and public health, while review literature continues to argue that dogs and cats need fuller inclusion in surveillance and containment plans. A reporting framework doesn’t solve every gap, but it creates the infrastructure needed to see patterns earlier and respond more consistently. (woah.org)

What to watch: The next question is whether this framework remains a paper model or becomes operational policy, through state-level reporting guidance, laboratory workflows, referral hospital protocols, and perhaps expanded use of confirmatory testing and genomic epidemiology for companion animal CRO detections. (vetlit.org)