Expansion of KPC-producing Enterobacterales in four large hospitals in Hanoi, Vietnam

Abstract

Objectives: The incidence of 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, bla_KPC, among carbapenem-resistant Enterobacterales (CRE) from four large hospitals in Hanoi, Vietnam, between 2010 and 2015, and described their key molecular characteristics.

Methods: KPC-producing Enterobacterales were detected using conventional PCR and were further analysed using S1 nuclease pulsed-field gel electrophoresis (S1-PFGE), Southern blotting and whole-genome sequencing (WGS) for sequence typing and genetic characterisation.

Results: bla_KPC genes were detected in 122 (20.4%) of 599 CRE isolates. bla_KPC-carrying plasmids were diverse in size. Klebsiella pneumoniae harbouring bla_KPC genes belonged to ST15 and ST11, whereas KPC-producing Escherichia 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 the years and of transmission among these hospitals via patient transfer. WGS results revealed co-carriage of several other antimicrobial resistance genes and three different genetic contexts of bla_KPC-2. Among these, the combination of ISEcp1-bla_CTX-M and ISKpn27-bla_KPC-ΔISKpn6 on the same plasmid is reported for the first time.

Conclusion: We describe the dissemination of bla_KPC-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 genetic context, thereby contributing to the overall picture of the antimicrobial resistance situation in Enterobacterales in Vietnam.

Keywords: Carbapenem resistance; Enterobacterales; KPC; Vietnam.

Fig. 1

Core genome phylogenetic tree of bla_KPC-carrying Klebsiella pneumoniae isolates. Presence of resistance genes was colour coded by different antibiotic categories, while grey blocks showed no corresponding resistance genes were detected.

Fig. 2

Core genome phylogenetic tree of bla_KPC-carrying Escherichia coli isolates. Presence of resistance genes was colour coded by different antibiotic categories, while grey blocks showed no corresponding resistance genes were detected.

Fig. 3

S1 nuclease pulsed-field gel electrophoresis (S1-PFGE) and Southern blotting of plasmids carrying bla_KPC from clinical isolates. (A) DNA fingerprint of S1-treated plasmid DNA of selected Enterobacterales from clinical isolates stained with ethidium bromide. (B) Autoradiogram of gel A showing plasmids carrying the bla_KPC gene. M, Salmonella Braenderup H9812 (molecular weight marker); lanes 1 and 4–8, Klebsiella pneumoniae isolates from hospital A; lanes 2 and 3, Escherichia coli isolates from hospital A; lanes 9–13, 23 and 24, K. pneumoniae isolates from hospital B; lane 14, K. pneumoniae from hospital C; lanes 15–19, K. pneumoniae isolates from hospital D; lanes 20 and 21, K. pneumoniae from hospital C; lane 22, E. coli isolates from hospital C.

Fig. 4

Gene context models of bla_KPC-2 in Escherichia coli and Klebsiella pneumoniae isolates. (I) Model observed in K. pneumoniae and E. coli isolates carrying 55-bp or 30-bp plasmids. (II) Model observed in K. pneumoniae isolates carrying 55-bp or 170-bp plasmids. (III) Model observed in K. pneumoniae isolates carrying 55-bp plasmids.