Assembly and characterization of a pathogen strain collection for produce safety applications: Pre-growth conditions have a larger effect on peroxyacetic acid tolerance than strain diversity

Anna Sophia Harrand, Jasna Kovac, Laura M. Carroll, Veronica Guariglia-Oropeza, David J. Kent, Martin Wiedmann

Research output: Contribution to journalArticle

Abstract

Effective control of foodborne pathogens on produce requires science-based validation of interventions and control strategies, which typically involves challenge studies with a set of bacterial strains representing the target pathogens or appropriate surrogates. In order to facilitate these types of studies, a produce-relevant strain collection was assembled to represent strains from produce outbreaks or pre-harvest environments, including Listeria monocytogenes (n = 11), Salmonella enterica (n = 23), Shiga-toxin producing Escherichia coli (STEC) (n = 13), and possible surrogate organisms (n = 8); all strains were characterized by whole genome sequencing (WGS). Strain diversity was assured by including the 10 most common S. enterica serotypes, L. monocytogenes lineages I-IV, and E. coli O157 as well as selected “non-O157” STEC serotypes. As it has previously been shown that strains and genetic lineages of a pathogen may differ in their ability to survive different stress conditions, a subset of representative strains for each “pathogen group” (e.g., Salmonella, STEC) was selected and assessed for survival of exposure to peroxyacetic acid (PAA) using strains pre-grown under different conditions including (i) low pH, (ii) high salt, (iii) reduced water activity, (iv) different growth phases, (v) minimal medium, and (vi) different temperatures (21°C, 37°C). The results showed that across the three pathogen groups pre-growth conditions had a larger effect on bacterial reduction after PAA exposure as compared to strain diversity. Interestingly, bacteria exposed to salt stress (4.5% NaCl) consistently showed the least reduction after exposure to PAA; however, for STEC, strains pre-grown at 21°C were as tolerant to PAA exposure as strains pre-grown under salt stress. Overall, our data suggests that challenge studies conducted with multi-strain cocktails (pre-grown under a single specific condition) may not necessarily reflect the relevant phenotypic range needed to appropriately assess different intervention strategies.

Original languageEnglish (US)
Article number1223
JournalFrontiers in Microbiology
Volume10
Issue numberMAY
DOIs
StatePublished - Jan 1 2019

Fingerprint

Peracetic Acid
Shiga-Toxigenic Escherichia coli
Safety
Salmonella enterica
Salts
Listeria monocytogenes
Growth
Escherichia coli O157
Salmonella
Disease Outbreaks
Genome
Bacteria
Temperature
Water
Serogroup

All Science Journal Classification (ASJC) codes

  • Microbiology
  • Microbiology (medical)

Cite this

@article{d5a52bb7b0224e12b96faf339f9ed0a5,
title = "Assembly and characterization of a pathogen strain collection for produce safety applications: Pre-growth conditions have a larger effect on peroxyacetic acid tolerance than strain diversity",
abstract = "Effective control of foodborne pathogens on produce requires science-based validation of interventions and control strategies, which typically involves challenge studies with a set of bacterial strains representing the target pathogens or appropriate surrogates. In order to facilitate these types of studies, a produce-relevant strain collection was assembled to represent strains from produce outbreaks or pre-harvest environments, including Listeria monocytogenes (n = 11), Salmonella enterica (n = 23), Shiga-toxin producing Escherichia coli (STEC) (n = 13), and possible surrogate organisms (n = 8); all strains were characterized by whole genome sequencing (WGS). Strain diversity was assured by including the 10 most common S. enterica serotypes, L. monocytogenes lineages I-IV, and E. coli O157 as well as selected “non-O157” STEC serotypes. As it has previously been shown that strains and genetic lineages of a pathogen may differ in their ability to survive different stress conditions, a subset of representative strains for each “pathogen group” (e.g., Salmonella, STEC) was selected and assessed for survival of exposure to peroxyacetic acid (PAA) using strains pre-grown under different conditions including (i) low pH, (ii) high salt, (iii) reduced water activity, (iv) different growth phases, (v) minimal medium, and (vi) different temperatures (21°C, 37°C). The results showed that across the three pathogen groups pre-growth conditions had a larger effect on bacterial reduction after PAA exposure as compared to strain diversity. Interestingly, bacteria exposed to salt stress (4.5{\%} NaCl) consistently showed the least reduction after exposure to PAA; however, for STEC, strains pre-grown at 21°C were as tolerant to PAA exposure as strains pre-grown under salt stress. Overall, our data suggests that challenge studies conducted with multi-strain cocktails (pre-grown under a single specific condition) may not necessarily reflect the relevant phenotypic range needed to appropriately assess different intervention strategies.",
author = "Harrand, {Anna Sophia} and Jasna Kovac and Carroll, {Laura M.} and Veronica Guariglia-Oropeza and Kent, {David J.} and Martin Wiedmann",
year = "2019",
month = "1",
day = "1",
doi = "10.3389/fmicb.2019.01223",
language = "English (US)",
volume = "10",
journal = "Frontiers in Microbiology",
issn = "1664-302X",
publisher = "Frontiers Media S. A.",
number = "MAY",

}

Assembly and characterization of a pathogen strain collection for produce safety applications : Pre-growth conditions have a larger effect on peroxyacetic acid tolerance than strain diversity. / Harrand, Anna Sophia; Kovac, Jasna; Carroll, Laura M.; Guariglia-Oropeza, Veronica; Kent, David J.; Wiedmann, Martin.

In: Frontiers in Microbiology, Vol. 10, No. MAY, 1223, 01.01.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Assembly and characterization of a pathogen strain collection for produce safety applications

T2 - Pre-growth conditions have a larger effect on peroxyacetic acid tolerance than strain diversity

AU - Harrand, Anna Sophia

AU - Kovac, Jasna

AU - Carroll, Laura M.

AU - Guariglia-Oropeza, Veronica

AU - Kent, David J.

AU - Wiedmann, Martin

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Effective control of foodborne pathogens on produce requires science-based validation of interventions and control strategies, which typically involves challenge studies with a set of bacterial strains representing the target pathogens or appropriate surrogates. In order to facilitate these types of studies, a produce-relevant strain collection was assembled to represent strains from produce outbreaks or pre-harvest environments, including Listeria monocytogenes (n = 11), Salmonella enterica (n = 23), Shiga-toxin producing Escherichia coli (STEC) (n = 13), and possible surrogate organisms (n = 8); all strains were characterized by whole genome sequencing (WGS). Strain diversity was assured by including the 10 most common S. enterica serotypes, L. monocytogenes lineages I-IV, and E. coli O157 as well as selected “non-O157” STEC serotypes. As it has previously been shown that strains and genetic lineages of a pathogen may differ in their ability to survive different stress conditions, a subset of representative strains for each “pathogen group” (e.g., Salmonella, STEC) was selected and assessed for survival of exposure to peroxyacetic acid (PAA) using strains pre-grown under different conditions including (i) low pH, (ii) high salt, (iii) reduced water activity, (iv) different growth phases, (v) minimal medium, and (vi) different temperatures (21°C, 37°C). The results showed that across the three pathogen groups pre-growth conditions had a larger effect on bacterial reduction after PAA exposure as compared to strain diversity. Interestingly, bacteria exposed to salt stress (4.5% NaCl) consistently showed the least reduction after exposure to PAA; however, for STEC, strains pre-grown at 21°C were as tolerant to PAA exposure as strains pre-grown under salt stress. Overall, our data suggests that challenge studies conducted with multi-strain cocktails (pre-grown under a single specific condition) may not necessarily reflect the relevant phenotypic range needed to appropriately assess different intervention strategies.

AB - Effective control of foodborne pathogens on produce requires science-based validation of interventions and control strategies, which typically involves challenge studies with a set of bacterial strains representing the target pathogens or appropriate surrogates. In order to facilitate these types of studies, a produce-relevant strain collection was assembled to represent strains from produce outbreaks or pre-harvest environments, including Listeria monocytogenes (n = 11), Salmonella enterica (n = 23), Shiga-toxin producing Escherichia coli (STEC) (n = 13), and possible surrogate organisms (n = 8); all strains were characterized by whole genome sequencing (WGS). Strain diversity was assured by including the 10 most common S. enterica serotypes, L. monocytogenes lineages I-IV, and E. coli O157 as well as selected “non-O157” STEC serotypes. As it has previously been shown that strains and genetic lineages of a pathogen may differ in their ability to survive different stress conditions, a subset of representative strains for each “pathogen group” (e.g., Salmonella, STEC) was selected and assessed for survival of exposure to peroxyacetic acid (PAA) using strains pre-grown under different conditions including (i) low pH, (ii) high salt, (iii) reduced water activity, (iv) different growth phases, (v) minimal medium, and (vi) different temperatures (21°C, 37°C). The results showed that across the three pathogen groups pre-growth conditions had a larger effect on bacterial reduction after PAA exposure as compared to strain diversity. Interestingly, bacteria exposed to salt stress (4.5% NaCl) consistently showed the least reduction after exposure to PAA; however, for STEC, strains pre-grown at 21°C were as tolerant to PAA exposure as strains pre-grown under salt stress. Overall, our data suggests that challenge studies conducted with multi-strain cocktails (pre-grown under a single specific condition) may not necessarily reflect the relevant phenotypic range needed to appropriately assess different intervention strategies.

UR - http://www.scopus.com/inward/record.url?scp=85068675629&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85068675629&partnerID=8YFLogxK

U2 - 10.3389/fmicb.2019.01223

DO - 10.3389/fmicb.2019.01223

M3 - Article

C2 - 31231329

AN - SCOPUS:85068675629

VL - 10

JO - Frontiers in Microbiology

JF - Frontiers in Microbiology

SN - 1664-302X

IS - MAY

M1 - 1223

ER -