Community Outbreak of OXA-48-Producing Escherichia coli Linked to Food Premises, New Zealand, 2018-2022

Abstract

In New Zealand, OXA-48-producing Escherichia coli is uncommon and typically associated with international travel. We investigated a cluster of 25 patients without recent travel history from Hutt Valley health district, New Zealand, who had multilocus sequence type 131 OXA-48-producing E. coli during August 2018-December 2022. Eighteen had been admitted to Hutt Valley Hospital but did not share a common ward or hospital service. Eighteen had visited the same community-based commercial food premises (premises A); 7 of those had not been admitted to Hutt Valley Hospital. An inspection of premises A revealed multiple hazards, primarily around staff hand hygiene. Four food handlers were colonized with OXA-48-producing E. coli; whole-genome sequencing confirmed genomic links between case and food handler strains, with possible introduction to New Zealand circa 2017. Community-based food premises have a role in propagating OXA-48-producing E. coli in high-income countries, requiring consideration in control strategies.

Keywords: Escherichia coli; New Zealand; antimicrobial resistance; bacteria; carbapenem-resistant Enterobacteriaceae; disease outbreaks; food safety; foodborne diseases; infectious disease transmission; molecular epidemiology.

Figure 1

Epidemic curve of 25 cases of OXA-48–producing Escherichia coli, by month of sample collection, in study of community outbreak linked to food premises, Hutt Valley, New Zealand, August 2018–December 2022. Cases are categorized according to history of exposure to a community-based food premises (premises A) and history of inpatient admission to Hutt Valley Hospital (HVH) in the 4-year period before detection: 7 had been exposed to premises A but not HVH (red), 11 had been exposed both to premises A and to HVH (blue), 6 had been exposed to HVH but not to premises A (green), and 1 person had been exposed to HVH but premises A exposure was unknown (yellow). CPE, carbapenemase-producing Enterobacterales.

Figure 2

Evolutionary reconstruction for OXA-48–producing Escherichia coli sequence type (ST)131 genomes obtained from cases and food handlers compared with publicly available genomes in study of community outbreak linked to food premises, Hutt Valley, New Zealand, August 2018–December 2022. A time-calibrated maximum clade credibility tree was inferred from 323 nonrecombinant orthologous biallelic core-genome single-nucleotide variants (SNVs) from 50 ST131 genomes. SNVs were derived from a core-genome alignment of ≈4,767,900 bp and were called against the chromosome of 18AR0845 (GenBank accession no. CP175691). The x-axis represents the emergence time estimates. Case numbers (1–25), shown in bold after the genome codes, correspond to case reference numbers shown in Appendix Table 2). Case numbers FH1–4 indicate genomes obtained from food handlers working at a community-based food premises to which 18 of the case-patients had been exposed. Asterisks indicate subsequent genomes obtained from the same case-patient or food handler.