Emergence of bla NDM-5-carrying Pseudescherichia vulneris and Pantoea dispersa isolated from the veterinary hospital environment

Abstract The emergence of carbapenem-resistant Enterobacterales (CRE) poses a critical threat to global health security. Veterinary hospitals may serve as potential hotspots for antimicrobial resistance (AMR) gene dissemination, yet surveillance in these environments remains limited. This study was carried out to screen the spread of CRE in the environment of a veterinary hospital. Totally, we collected 283 environmental swab samples from a veterinary hospital in Guangzhou, China. The samples were screened for meropenem-resistant isolates, and polymerase chain reaction amplification was performed to detect bla NDM genes. Species identification was performed using matrix-assisted laser desorption ionization-time of flight mass spectrometry. Two isolates representing previously unreported bla NDM-positive species were selected for whole-genome sequencing. Thirty-two meropenem-resistant isolates were recovered, with 15 isolates (5.3%) testing positive for bla NDM genes. All the bla NDM-positive isolates belonged to Enterobacterales, including one isolate each of Pseudescherichia vulneris and Pantoea dispersa, representing the first reported bla NDM-positive strains of these species. Whole-genome sequencing of these two isolates revealed that both harbored bla NDM-5 genes on IncX3 plasmids with conjugation frequencies of 7.5 × 10⁻5 and 6.0 × 10⁻5, respectively. The P. dispersa strain exhibited high genetic similarity (core-genome single nucleotide polymorphisms = 12) to isolates of Oryza sativa origin from India lacking bla NDM genes, suggesting recent plasmid acquisition. The detection of bla NDM-5 in these previously unreported host species is concerning given their exceptional environmental persistence and stress tolerance. These findings highlight the urgent need for enhanced One Health surveillance approaches encompassing veterinary environments as critical components of AMR networks.