The emergence and spread of resistance to last-resort antibiotics such as tigecycline is of great concern globally which can pose a potential threat to public health due to limited treatment options. In this study, we first identified and characterized the genomic features of a food-acquired Raoultella ornithinolytica strain co-harboring tet (X4) and tmexCD1-toprJ1 genes through antibiotic susceptibility testing and whole genome sequencing, followed by global comparative analysis of Raoultella ornithinolytica genomes submitted in National Center for Biotechnology Information (NCBI) database. Raoultella ornithinolytica LYG₆₁B exhibited high-level tigecycline resistance and multi-drug resistance. The genomic analysis revealed that LYG₆₁B harbored 32 antibiotic resistance genes (e. g. , tetracycline, sulfonamides, trimethoprim, aminoglycosides, fluoroquinolone, phenicol, β-lactam, macrolides, and rifampicin), 14 virulence genes (e. g. , ecpA, ompA, entB, irp1, irp2, ybtAEPQSTUX, fyuA, entB), and three plasmids. The tet (X4) was found to be located on 79Kb IncFII (pCRY) plasmid and tmexCD1-toprJ1 on 290Kb hybrid plasmid IncFIB (pNDM-Mar) + IncHI1B (pNDM-Mar). Both of the genes, tet (X4) and tmexCD1-toprJ1 were found to be located on separate conjugative plasmids via the conjugation assay. This indicates the expanding host range and independent horizontal transfer potential of these critical resistance genes across bacterial species or genera in One Health settings. Therefore, the current study recommends the continuous genomic surveillance of bacterial strains in food supply chain and other One Health settings to monitor and prevent their further dissemination. Moreover, the emergence of critical resistance genes in food-origin bacteria can pose a direct threat to human health. • This study first identified and provides the genomic characteristics of tet (X4) and tmexCD1-toprJ1 in R. ornithinolytica strain from a retail pork. • The tet (X4) and tmexCD1-toprJ1 harboring plasmids are transferable and has the potential to spread globally among One Health components. • Global genomic analysis revealed the potential risks to animal, human, and environmental health.
Shoaib et al. (Sun,) studied this question.