A Survey of Current Activities and Technologies Used to Detect Carbapenem Resistance in Bacteria Isolated from Companion Animals at Veterinary Diagnostic Laboratories-United States, 2020

Abstract

Carbapenems are antimicrobial drugs reserved for the treatment of severe multidrug-resistant Gram-negative bacterial infections. Carbapenem-resistant organisms (CROs) are an urgent public health threat and have been made reportable to public health authorities in many jurisdictions. Recent reports of CROs in companion animals and veterinary settings suggest that CROs are a One Health problem. However, standard practices of U.S. veterinary diagnostic laboratories (VDLs) to detect CROs are unknown. We assessed the capacity of VDLs to characterize carbapenem resistance in isolates from companion animals. Among 74 VDLs surveyed in 42 states, 23 laboratories (31%) from 22 states responded. Most (22/23, 96%) included ≥1 carbapenem on their primary antimicrobial susceptibility testing panel, and approximately one-third (9/23, 39%) performed phenotypic carbapenemase production testing or molecular identification of carbapenemase genes. Overall, 35% (8/23) of VDLs across eight states reported they would notify public health if a CRO was detected. Most (17/21, 81%) VDLs were not aware of CRO reporting mandates, and some expressed uncertainty about whether the scope of known mandates included CROs from veterinary sources. Although nearly all surveyed VDLs tested for carbapenem resistance, fewer had the capacity for mechanism testing or awareness of public health reporting requirements. Addressing these gaps is critical to monitoring CRO incidence and trends in veterinary medicine, preventing spread in veterinary settings, and mounting an effective One Health response. Improved collaboration and communication between public health and veterinary medicine is critical to inform infection control practices in veterinary settings and conduct a public health response when resistant isolates are detected.

Keywords: carbapenems; veterinary diagnostic laboratory; veterinary epidemiology.

FIG 1

Number of veterinary diagnostic laboratories in the United States reporting isolates from companion animals resistant to carbapenem, by the number of isolates, from January 1, 2019 to June 30, 2020. Companion animals were defined as dogs or cats. Two laboratories did not provide information on laboratory test results. Twenty laboratories reported the number of Enterobacterales isolates resistant to a carbapenem, 18 reported the number of P. aeruginosa isolates resistant to a carbapenem, and 16 reported the number of A. baumannii isolates resistant to a carbapenem.

FIG 2

Reported actions that would be initiated if carbapenem resistance was detected in a companion animal isolate among 23 veterinary diagnostic laboratories (VDLs) in the United States from January 1, 2019 to June 30, 2020. Companion animals were defined as dogs and cats. ^a, includes two laboratories that did not provide a response and one laboratory that answered ‘unknown’ to the question if any carbapenem-resistant isolate(s) were detected from a companion animal from January 1, 2019–June 30, 2020; ^b, actions sum to >100% because responses are not mutually exclusive; ^c, these actions included either notifying the state veterinarian and/or notifying another public health official or department; ^d, isolates would likely be sent through Vet-LIRN.