Type

Journal Article

Authors

R Paul Ross
Paul D. Cotter
Colin Hill
Evelyn M Clayton

Subjects

Microbiology

Topics
virulence factors bacteriological techniques isolation purification enzymology genetics hemolysin proteins listeria monocytogenes classification listeriolysin s listeria monocytogenes gene deletion sensitivity and specificity polymerase chain reaction food microbiology

Real-time PCR assay to differentiate Listeriolysin S-positive and -negative strains of Listeria monocytogenes. (2010)

Abstract Due to the severity of the food-borne infection listeriosis, strict legislation governs the detectable and permissible limits at which Listeria monocytogenes is permitted in foods. These requirements, coupled with the ubiquitous nature of L. monocytogenes strains and the potential for epidemic outbreaks, mean that the pathogen can devastate affected sectors of the food industry. Although almost all L. monocytogenes strains have the potential to cause listeriosis, those implicated in the vast majority of epidemics belong to a subset of strains belonging to evolutionary lineage I. It has been established that a significant proportion of these strains, including those implicated in the majority of outbreaks, produce an additional hemolysin, designated listeriolysin S (LLS), which may be responsible for the enhanced virulence of these strains. In order to ultimately establish this definitively, it is important to first be able to rapidly discriminate between LLS-positive and -negative strains. Here, after essential genes within the LLS-encoding cluster, Listeria pathogenicity island 3, were identified by deletion mutagenesis, a real-time PCR assay which targets one such gene, llsX, was developed as a means of identifying LLS-positive L. monocytogenes. The specificity of the assay was validated against a panel of 40 L. monocytogenes strains (20 of which were LLS positive) and 25 strains representative of other Listeria species. Furthermore, 1 CFU of an LLS-positive strain per 25 g/ml of spiked foods was detected in less than 30 h when the assay was coupled with culture enrichment. The detection limit of this assay was 10 genome equivalents.
Collections Ireland -> University College Cork -> PubMed

Full list of authors on original publication

R Paul Ross, Paul D. Cotter, Colin Hill, Evelyn M Clayton

Experts in our system

1
R Paul Ross
Teagasc
Total Publications: 441
 
2
Paul D. Cotter
Teagasc
Total Publications: 253
 
3
Colin Hill
University College Cork
Total Publications: 351
 
4
Evelyn M Clayton
Teagasc
Total Publications: 7