Virulence genes expression in Literia monocytogenes strains isolated from clinical samples and food exposed to diferent growth conditions

Abstract

Listeria monocytogenes is an opportunistic foodborne pathogen responsible for listeriosis, a disease with high mortality rates. The control of this pathogen in food processing plants is one of the most difficult processes because it may form biofilms and it easily adapts itself to adverse environmental conditions. L. monocytogenes serotype 4b is the most frequently isolate in clinical cases, while the serotype 1/2a is usually isolated in foods and environment. The reason for this incidence remains unknown. Some studies have been conducted in order to understand whether 4b or 1/2a strains differ regarding virulence genes expression or even if they have different protection mechanisms to environmental stress. This study aims to verify if the osmotic and/or heat stresses have any influence on the expression of virulence genes of L. monocytogenes serotypes 1/2a and 4b, isolated in Brazil from clinical samples and foods. The results will help us to understand the pathogen behavior in food processing conditions, and may be used in developing strategies for its control. (AU)