High Frequency of Detection of NDM-Producing Enterobacterales Among Companion Animals Hospitalized in an Italian...

Carbapenems are considered one of the most important last-resort classes of antibiotics, and the spread of carbapenem-resistant Enterobacterales (CRE) is a serious concern worldwide. From a One Health point of view, reports on CRE in companion animals are increasing, requiring attention regarding their role in maintenance and direct transmission to humans. The aim of this study was to assess the frequency of detection at admission and the in-hospital acquisition of CRE from perirectal swabs in dogs and cats hospitalized in an Italian Veterinary Teaching Hospital (VTH). Of the 150 patients sampled, 11.3% (n = 17) were CRE carriers at admission, 25.6% (n = 34) acquired CRE in their commensal microbiota during their hospital stay, and 2% (n = 3) developed an infection caused by CRE. Genotypical analysis showed that in 100% (78/78) of the CRE isolates (44 Escherichia coli, 33 Klebsiella pneumoniae, and 1 Klebsiella aerogenes) carbapenem resistance was conferred by the carbapenemase gene bla_NDM, suggesting an endemic presence of such gene within the hospital. Co-occurrent β-lactamase-encoding genes were found in most of the isolates. Risk factors associated with CRE acquisition were length of hospitalization (p=0.0002) and treatment with piperacillin-tazobactam (PTZ; p=0.0380), indicating potential cross-selection of CRE. These results reinforce the suspicion that companion animals could silently contribute to the maintenance and dissemination of CRE in the local community, posing a threat to global health.