Phenotypic and genotypic analysis of persistent and sporadic isolates of listeria monocytogenes
type: CreativeWork
description: The foodborne pathogen Listeria monocytogenes has the ability to persist for months to years within food-associated environments. These persistent strains maintain a constant risk of contamination and it is vital to identify and eliminate these persistent strains as soon as possible. Previous work has identified and characterized putative persistent and sporadic isolates from 30 retail delis in three regions of the U.S. over six months. Next generation sequencing allowed phylogenetic relationships to identify persistent strains based on the assumption that isolates of a persistent strain were more closely related than isolates of sporadic strains. Those studies provided the isolates and genomic data to investigate additional phenotypic and genotypic properties that may differentiate persistent and sporadic strains. In this present work, two questions were examined. (i) Do isolates of persistent strains contain distinct CRISPR spacers? (ii) Do isolates of persistent strains have higher growth rates or ability to grow in various stressful conditions or carbon sources associated with food environments? CRISPRs, or clustered regularly interspaced short palindromic repeats, are comprised of pieces of foreign DNA (spacers) and are sandwiched between repeated sequences of host DNA (directed repeats). The foreign DNA is integrated into a bacteria’s genome to act as a defense mechanism against foreign invading DNA, like bacteriophages. The integrated DNA, spacers, act like a logbook of which bacteriophages or foreign invaders have collided with a strain. Since persistent strains survive in environments for an extended period of time, and phages are common within food-associated environments, isolates of a persistent strain may contain more or different spacers than sporadic isolates. Viewing the bioinformatic analysis of previously sequenced persistent and sporadic isolates from retail delis, 174 of 175 L. monocytogenes isolates contained CRISPR spacer arrays that contained,…
abstract: The foodborne pathogen Listeria monocytogenes has the ability to persist for months to years within food-associated environments. These persistent strains maintain a constant risk of contamination and it is vital to identify and eliminate these persistent strains as soon as possible. Previous work has identified and characterized putative persistent and sporadic isolates from 30 retail delis in three regions of the U.S. over six months. Next generation sequencing allowed phylogenetic relationships to identify persistent strains based on the assumption that isolates of a persistent strain were more closely related than isolates of sporadic strains. Those studies provided the isolates and genomic data to investigate additional phenotypic and genotypic properties that may differentiate persistent and sporadic strains. In this present work, two questions were examined. (i) Do isolates of persistent strains contain distinct CRISPR spacers? (ii) Do isolates of persistent strains have higher growth rates or ability to grow in various stressful conditions or carbon sources associated with food environments? CRISPRs, or clustered regularly interspaced short palindromic repeats, are comprised of pieces of foreign DNA (spacers) and are sandwiched between repeated sequences of host DNA (directed repeats). The foreign DNA is integrated into a bacteria’s genome to act as a defense mechanism against foreign invading DNA, like bacteriophages. The integrated DNA, spacers, act like a logbook of which bacteriophages or foreign invaders have collided with a strain. Since persistent strains survive in environments for an extended period of time, and phages are common within food-associated environments, isolates of a persistent strain may contain more or different spacers than sporadic isolates. Viewing the bioinformatic analysis of previously sequenced persistent and sporadic isolates from retail delis, 174 of 175 L. monocytogenes isolates contained CRISPR spacer arrays that contained,…
author: Taylor, Alexander Joseph
language: en
keywords: Listeria monocytogenes, persistence, CRISPR, subtyping, phenotyping, stress response, growth curves, carbohydrate utilization
date published: 2019-02-06T19:32:42Z
date modified: 2026-07-22T22:24:40Z
provider: University of Illinois - Urbana-Champaign
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Illinois at Urbana-Champaign

PropertyValue
property ID: Handle
value: http://hdl.handle.net/2142/102404