Characterisation of the novel transposon Tn7722 harbouring blaNDM-1: Insights into the evolutionary dynamics of resistance in Klebsiella pneumoniae
Abstract
Background: Klebsiella pneumoniae is an opportunistic pathogen responsible for invasive infections. The rise of carbapenem-resistant K. pneumoniae , largely driven by acquisition of bla NDM genes, represents a global health threat. In French Polynesia, sporadic cases of NDM-producing Enterobacteriales have been reported. This study characterises the genomic features of NDM-producing K. pneumoniae isolates from French Polynesia and evaluates the roles of clonal expansion and mobile genetic element (MGE)-mediated horizontal gene transfer in bla NDM dissemination. Materials and methods: Between July 2006 and September 2021, 17 carbapenemase-producing K. pneumoniae isolates were identified among 715 clinical samples in Tahiti. Whole-genome sequencing using Illumina MiSeq and Oxford Nanopore technologies was performed. Results: Seven NDM-producing K. pneumoniae strains were identified, five bla NDM-1 and two bla NDM-9 variants. All were resistant to ertapenem (MICs 1 to > 32 mg/L), with three resistant to imipenem (MICs 8 to > 32 mg/L) and six to meropenem (MICs 2 to > 8 mg/L). A novel IS 26 -mediated composite transposon, Tn 7722 (16 246 bp), carrying bla NDM-1 , qnrS1 and aph(3 )-VI genes, was detected in four isolates on IncF and IncR plasmids. Tn 7722 -like elements were found in diverse bacterial genomes worldwide, suggesting that they facilitates bla NDM transmission across multiple species and regions. Conclusion: NDM-producing K. pneumoniae in French Polynesia remain sporadic but genetically diverse, without evidence of local outbreak. This suggests a contribution of plasmid and Tn 7722 -associated elements to the diversity and evolution of carbapenem resistance. Ongoing genomic surveillance is vital to track the evolution of high-risk clones and MGEs guiding effective containment.
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BibTeX
@article{vo2026characterisation,
title = {{Characterisation of the novel transposon Tn7722 harbouring blaNDM-1: Insights into the evolutionary dynamics of resistance in Klebsiella pneumoniae}},
author = {Tram Vo and Aïcha Hamieh and Marc Levy and Pierre Pontarotti and Jean-Marc Rolain and Vicky Merhej},
journal = {Journal of Global Antimicrobial Resistance},
year = {2026},
month = sep,
doi = {10.1016/j.jgar.2026.09.007},
url = {https://amu.hal.science/hal-05848979v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Characterisation of the novel transposon Tn7722 harbouring blaNDM-1: Insights into the evolutionary dynamics of resistance in Klebsiella pneumoniae
AU - Tram Vo
AU - Aïcha Hamieh
AU - Marc Levy
AU - Pierre Pontarotti
AU - Jean-Marc Rolain
AU - Vicky Merhej
PY - 2026
DA - 2026/09/19
JO - Journal of Global Antimicrobial Resistance
DO - 10.1016/j.jgar.2026.09.007
UR - https://amu.hal.science/hal-05848979v1
AB - Background: Klebsiella pneumoniae is an opportunistic pathogen responsible for invasive infections. The rise of carbapenem-resistant K. pneumoniae , largely driven by acquisition of bla NDM genes, represents a global health threat. In French Polynesia, sporadic cases of NDM-producing Enterobacteriales have been reported. This study characterises the genomic features of NDM-producing K. pneumoniae isolates from French Polynesia and evaluates the roles of clonal expansion and mobile genetic element (MGE)-mediated horizontal gene transfer in bla NDM dissemination. Materials and methods: Between July 2006 and September 2021, 17 carbapenemase-producing K. pneumoniae isolates were identified among 715 clinical samples in Tahiti. Whole-genome sequencing using Illumina MiSeq and Oxford Nanopore technologies was performed. Results: Seven NDM-producing K. pneumoniae strains were identified, five bla NDM-1 and two bla NDM-9 variants. All were resistant to ertapenem (MICs 1 to > 32 mg/L), with three resistant to imipenem (MICs 8 to > 32 mg/L) and six to meropenem (MICs 2 to > 8 mg/L). A novel IS 26 -mediated composite transposon, Tn 7722 (16 246 bp), carrying bla NDM-1 , qnrS1 and aph(3 )-VI genes, was detected in four isolates on IncF and IncR plasmids. Tn 7722 -like elements were found in diverse bacterial genomes worldwide, suggesting that they facilitates bla NDM transmission across multiple species and regions. Conclusion: NDM-producing K. pneumoniae in French Polynesia remain sporadic but genetically diverse, without evidence of local outbreak. This suggests a contribution of plasmid and Tn 7722 -associated elements to the diversity and evolution of carbapenem resistance. Ongoing genomic surveillance is vital to track the evolution of high-risk clones and MGEs guiding effective containment.
SN - 2213-7165
SN - 2213-7173
ER -