African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5233

Full Length Research Paper

RT-PCR assays for the evaluation of the expression of Listeria monocytogenes virulence genes after cold and freezing shock

Hanene MILADI1*, Kamel CHAIEB1, Mejdi SNOUSSI1, Emna AMMAR2 and Amina BAKHROUF1
1Laboratoire d’Analyses, Traitement et Valorisation des Polluants de l’Environnement et des Produits, Faculté de Pharmacie, rue Avicenne 5000 Monastir, Tunisie. 2Unité de Recherche Gestion des Environnements Urbains et Côtiers – LARSEN Ecole Nationale d’Ingénieurs de Sfax (Tunisie), B.P. « W »  3038  Sfax, Tunisie.
Email: [email protected]

  •  Accepted: 15 February 2013
  •  Published: 19 February 2013


Listeria monocytogenes is a food-borne bacterial pathogen that is able to grow at refrigeration temperatures and resist freezing. This organism frequently colonizes and proliferates on preserved food products despite exposure to stress conditions induced by low storage temperatures. To investigate microbial virulence genes expression associated with cold shock, RT-PCR (Reverse Transcript PCR) assays was applied inthree isolated strains L. monocytogenes and reference strain ATCC 19115. These included cDNAs for Lmonocytogenes genes involved in previously described virulences genes (hlyAiapflaAfrifbp) who cold-adaptive response is flaA, cold shock response isfri, cell surface alterations were fbp, and flaA, and the general microbial stress response (σβ) which contributed to such stress resistance. Transcription of virulence genes was significantly increased after cold and freezing stress of different virulence genes used in this study. Transcript level for the σβ gene was significantly affected by the factor temperature. These findings therefore suggest important roles of virulence genes and σβfactor to controls L. monocytogenes organisms against stress conditions associated with low storage temperatures.


Key words: Listeria monocytogenes, cold stress, virulence, expression