Multi-species plasmids and K. pneumoniae clonal spread contribute to bla NDM outbreak across seven UK healthcare sites.
7 affiliations
- 1Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK.
- 2Liverpool Clinical Laboratories, NHS University Hospitals of Liverpool Group, Liverpool, UK.
- 3Infection, Prevention and Control, Clatterbridge Cancer Centre NHS Foundation Trust, Liverpool, UK.
- 4Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK.
- 5Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.
- 6Department of Clinical Infection, Microbiology and Immunology, University of Liverpool, Liverpool, UK.
- 7Tropical and Infectious Diseases Unit, NHS University Hospitals of Liverpool Group, Liverpool, UK.
Abstract
Objectives
The NDM carbapenemase enables Gram-negative bacteria to hydrolyse almost all β-lactam antibiotics. In 2023, a large increase of bla NDM in clinical isolates was identified in a clinical microbiology laboratory serving hospitals and GP practices in Merseyside, UK, raising concerns of a larger outbreak.Methods
We used short-read WGS and bioinformatic analyses to identify the outbreak(s) and identify potential links by combining with anonymized, routinely collected clinical metadata. A subset of isolates were long-read sequenced to analyse resistance genes and plasmids at maximum resolution.Results
The outbreak included Enterobacter hormaechei, Klebsiella pneumoniae, Escherichia coli, Citrobacter freundii, Citrobacter braakii and Enterobacter kobei and 28 STs. K. pneumoniae ST101 represented the only major clonal expansion (18/21 K. pneumoniae isolates), and combination with metadata strongly suggested a multi-site hospital-associated outbreak. We identified four variants of bla NDM, and long-read sequencing indicated bla NDM-1 spread across species was driven by an IncHI2/IncHI2A plasmid, representing 82% of bla NDM1 isolates.Conclusions
This study captured an outbreak of bla NDM-positive Enterobacterales across eight healthcare settings and highlights the complex epidemiology of spread mediated by both expansion of successful lineages (K. pneumoniae ST101) and multi-species plasmids (IncHI2/IncHI2A). It also highlights the challenge of recognizing and tracing an outbreak linked to patients moving across different healthcare systems and the importance of linked surveillance systems.
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BibTeX
@article{duggan2026multispecies,
title = {{Multi-species plasmids and K. pneumoniae clonal spread contribute to bla NDM outbreak across seven UK healthcare sites.}},
author = {Caitlin Duggan and Charlotte Brookfield and David Lawrie and Victoria Owen and Timothy Neal and James Cruise and Alice J Fraser and Lewis Kelly and Fabrice E Graf and Daire Cantillon and Joseph M Lewis and Thomas Edwards and Eva Heinz},
journal = {JAC-antimicrobial resistance},
year = {2026},
month = oct,
doi = {10.1093/jacamr/dlag216},
url = {https://europepmc.org/article/MED/42923578},
note = {CC BY},
}
RIS
TY - JOUR
TI - Multi-species plasmids and K. pneumoniae clonal spread contribute to bla NDM outbreak across seven UK healthcare sites.
AU - Caitlin Duggan
AU - Charlotte Brookfield
AU - David Lawrie
AU - Victoria Owen
AU - Timothy Neal
AU - James Cruise
AU - Alice J Fraser
AU - Lewis Kelly
AU - Fabrice E Graf
AU - Daire Cantillon
AU - Joseph M Lewis
AU - Thomas Edwards
AU - Eva Heinz
PY - 2026
DA - 2026/10/22
JO - JAC-antimicrobial resistance
DO - 10.1093/jacamr/dlag216
UR - https://europepmc.org/article/MED/42923578
AB - Objectives The NDM carbapenemase enables Gram-negative bacteria to hydrolyse almost all β-lactam antibiotics. In 2023, a large increase of bla NDM in clinical isolates was identified in a clinical microbiology laboratory serving hospitals and GP practices in Merseyside, UK, raising concerns of a larger outbreak.Methods We used short-read WGS and bioinformatic analyses to identify the outbreak(s) and identify potential links by combining with anonymized, routinely collected clinical metadata. A subset of isolates were long-read sequenced to analyse resistance genes and plasmids at maximum resolution.Results The outbreak included Enterobacter hormaechei, Klebsiella pneumoniae, Escherichia coli, Citrobacter freundii, Citrobacter braakii and Enterobacter kobei and 28 STs. K. pneumoniae ST101 represented the only major clonal expansion (18/21 K. pneumoniae isolates), and combination with metadata strongly suggested a multi-site hospital-associated outbreak. We identified four variants of bla NDM, and long-read sequencing indicated bla NDM-1 spread across species was driven by an IncHI2/IncHI2A plasmid, representing 82% of bla NDM1 isolates.Conclusions This study captured an outbreak of bla NDM-positive Enterobacterales across eight healthcare settings and highlights the complex epidemiology of spread mediated by both expansion of successful lineages (K. pneumoniae ST101) and multi-species plasmids (IncHI2/IncHI2A). It also highlights the challenge of recognizing and tracing an outbreak linked to patients moving across different healthcare systems and the importance of linked surveillance systems.
SN - 2632-1823
ER -