Emergence and transmission of the high-risk ST78 clone of OXA-48-producing in a single hospital in Taiwan.

Carbapenem-resistant complex is a significant global healthcare threat, particularly carbapenemase-producing (CPEH). From January 2017 to January 2021, twenty-two CPEH isolates from a regional teaching hospital in central Taiwan were identified with the carriage of carbapenemase genes , and predominantly . Over 80% of these CPEH strains clustered into the high-risk ST78 lineage, carrying a IncL plasmid (pOXA48-CREH), nearly identical to the endemic plasmid pOXA48-KP in ST11 . This OXA-48-producing ST78 lineage disseminated clonally from 2018 to 2021 and transferred pOXA48-CREH to ST66 and ST90 . An IMP-8-producing ST78 strain harbouring a -carrying pIncHI2 plasmid appeared in 2018, and by late 2020, a KPC-2-producing ST78 strain was identified after acquiring a novel -carrying IncFII plasmid. These findings suggest that the high-risk ST78 lineage of . has emerged as the primary driver behind the transmission of CPEH ST78 has not only acquired various carbapenemase-gene-carrying plasmids but has also facilitated the transfer of pOXA48-CREH to other lineages. Continuous genomic surveillance and targeted interventions are urgently needed to control the spread of emerging CPEH clones in hospital settings.