HOMEPRODUCTSCOMPANYCONTACTFAQResearchDictionaryPharmaSign Up FREE or Login

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

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.
AuthorsEvelyn M Clayton, Colin Hill, Paul D Cotter, R Paul Ross
JournalApplied and environmental microbiology (Appl Environ Microbiol) Vol. 77 Issue 1 Pg. 163-71 (Jan 2011) ISSN: 1098-5336 [Electronic] United States
PMID21075895 (Publication Type: Evaluation Study, Journal Article, Research Support, Non-U.S. Gov't)
Chemical References
  • Hemolysin Proteins
  • Virulence Factors
  • listeriolysin S, Listeria monocytogenes
Topics
  • Bacteriological Techniques (methods)
  • Food Microbiology
  • Gene Deletion
  • Hemolysin Proteins (genetics)
  • Listeria monocytogenes (classification, enzymology, genetics, isolation & purification)
  • Polymerase Chain Reaction (methods)
  • Sensitivity and Specificity
  • Virulence Factors (genetics)

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research graph!


Choose Username:
Email:
Password:
Verify Password:
Enter Code Shown: