Short communication: Global clones of CTX-M-15-producing Enterobacterales, including the high-risk Enterobacter hormaechei ST78 in a veterinary teaching hospital

Extended-spectrum β-lactamases (ESBLs), particularly CTX-M enzymes, represent a significant concern among Enterobacterales. This cross-sectional, descriptive study reports the first detection and genomic characterization of CTX-M-15-producing Enterobacter hormaechei and Leclercia adecarboxylata recovered from high-contact surfaces in a Brazilian veterinary teaching hospital, based on analysis of 12 environmental samples. Three multidrug-resistant isolates were identified: E. hormaechei ST78 (UFRGS-TABLE-2023), E. hormaechei ST68 (UFRGS-TAP-2023), and L. adecarboxylata (UFRGS-BED-2023), all carrying bla CTX-M-15 , bla TEM-1B , bla OXA-1 , and additional resistance genes to aminoglycosides, quinolones, sulfonamides, and tetracyclines. IncHI2 plasmids harboring bla CTX-M-15 were detected in UFRGS-BED-2023 and UFRGS-TAP-2023 and showed high sequence similarity to a previously described human E. hormaechei plasmid. Phylogenomic analysis placed the isolates within globally distributed lineages. Although descriptive in nature and not intended to infer prevalence or transmission dynamics, these findings highlight veterinary hospital surfaces as potential reservoirs of antimicrobial resistance and support the need for integrated One Health surveillance. • Multidrug-resistant ESBL-producing Enterobacterales were isolated from high-contact surfaces of a Brazilian veterinary teaching hospital. • CTX-M-15–producing Enterobacter hormaechei ST68, ST78, and Leclercia adecarboxylata were identified through phenotypic and genomic analysis. • All isolates carried multiple AMR determinants, including blaCTX-M-15, blaTEM-1B, blaOXA-1, and genes for resistance to aminoglycosides, quinolones, sulfonamides, and tetracyclines. • IncHI2 plasmids showed near-complete identity (99.99%) to a human-derived E. hormaechei plasmid from the USA, suggesting circulation of similar genomes. • Phylogenomics revealed clustering of veterinary hospital isolates with international human strains, indicating global dissemination of high-risk clones. • Findings highlight veterinary hospitals as environmental