Nonculturable Escherichia coli O157 in horticultural compost
Nonculturable Escherichia coli O157 in horticultural compost
Fresh produce-associated outbreaks of the foodborne pathogen Escherichia coli O157 are responsible for a number of disease cases, hospitalizations and deaths. In many cases, the source of contamination can be linked to the growing media of the food, although pathogen detection is problematic in these complex soil ecosystems. In this study, direct quantitative real-time PCR without pre-enrichment was used to detect 310 copies of the Tir gene, using a primer sequence specific to E. coli O157, in horticultural compost purchased from a commercial supplier. The pathogen could not be cultured on selective media but was visualized using peptide nucleic acid fluorescence in situ hybridization and cell elongation viability assay, confirming the viability. Enumeration of elongated E. coli O157 determined that there were 205 live cells per gram of compost. The nonculturability and confirmation of viability of the pathogen indicates its viable but nonculturable (VBNC) status. The detection of VBNC foodborne pathogens in environmental samples challenges current understanding of the nature of foodborne pathogen contamination.
Escherichia coli O157, microbial detection, viable but nonculturable (VBNC)
Highmore, Callum
04809bd8-7cad-4dcf-b67d-264697f893b9
Keevil, C. William
cb7de0a7-ce33-4cfa-af52-07f99e5650eb
16 October 2025
Highmore, Callum
04809bd8-7cad-4dcf-b67d-264697f893b9
Keevil, C. William
cb7de0a7-ce33-4cfa-af52-07f99e5650eb
Highmore, Callum and Keevil, C. William
(2025)
Nonculturable Escherichia coli O157 in horticultural compost.
Access Microbiology, 7 (10), [001090.v4].
(doi:10.1099/acmi.0.001090.v4).
Abstract
Fresh produce-associated outbreaks of the foodborne pathogen Escherichia coli O157 are responsible for a number of disease cases, hospitalizations and deaths. In many cases, the source of contamination can be linked to the growing media of the food, although pathogen detection is problematic in these complex soil ecosystems. In this study, direct quantitative real-time PCR without pre-enrichment was used to detect 310 copies of the Tir gene, using a primer sequence specific to E. coli O157, in horticultural compost purchased from a commercial supplier. The pathogen could not be cultured on selective media but was visualized using peptide nucleic acid fluorescence in situ hybridization and cell elongation viability assay, confirming the viability. Enumeration of elongated E. coli O157 determined that there were 205 live cells per gram of compost. The nonculturability and confirmation of viability of the pathogen indicates its viable but nonculturable (VBNC) status. The detection of VBNC foodborne pathogens in environmental samples challenges current understanding of the nature of foodborne pathogen contamination.
Text
acmi001090.v4
- Version of Record
More information
e-pub ahead of print date: 16 October 2025
Published date: 16 October 2025
Keywords:
Escherichia coli O157, microbial detection, viable but nonculturable (VBNC)
Identifiers
Local EPrints ID: 507099
URI: http://eprints.soton.ac.uk/id/eprint/507099
ISSN: 2516-8290
PURE UUID: a6028b97-6871-49af-a222-41bcd0c5c341
Catalogue record
Date deposited: 26 Nov 2025 17:51
Last modified: 27 Nov 2025 02:55
Export record
Altmetrics
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics
