LAUSR

OBJECTIVES Carbapenem resistance among nosocomial Gram-negative bacteria in Vietnam is high and increasing, including among Enterobacterales. In this study, we assessed the presence of one of the main carbapenemase genes, blaKPC, among carbapenem-resistant Enterobacterales from four large hospitals in Hanoi, Vietnam, between 2010 and 2015, and described the key molecular characteristics. METHODS KPC-producing Enterobacterales were detected using conventional PCR and further analysed using S1-PFGE, Southern blotting and whole genome sequencing for sequence typing and genetic characterization. RESULTS blaKPC genes were detected in 122 out of 599 carbapenem resistant Enterobacterales isolates (20.4%). blaKPC-carrying plasmids were diverse in size. K. pneumoniae harbouring blaKPC genes belonged to ST15 and ST11 whereas KPC-producing E. coli showed more diverse sequence types including ST3580, ST448, ST709 and ST405. Genotypic relationships supported the hypothesis of circulation of a population of "resident" resistant bacteria in one hospital through years and transmission among these hospitals via patient transfer. Whole genome sequencing results revealed co-carriage with several other drug resistance genes and 3 different genetic contexts of blaKPC-2. Among those, the combination of ISEcp1-blaCTX-M and ISKpn27-blaKPC-∆ISKpn6 on the same plasmid is reported for the first time. CONCLUSIONS We describe the dissemination of blaKPC-expressing Enterobacterales in four large hospitals in Hanoi, Vietnam since 2010, which may have started earlier, along with their resistance patterns, sequence types, genotypic relationship, plasmid sizes and gene context models, thereby contributing to the overall picture of the antimicrobial resistance situation in Vietnam.