Listeria monocytogenes Pathogenicity

Listeria monocytogenes Pathogenicity

1. Survivability

   • Biofilms
   • Growth in cold temperatures
     • Would subjecting cells to stress reduce growth?
   • Low pH
     • Upregulation of Virulence
   • Proteolytic enzymes
   • RTE food susceptibility
     • Post Processing Contamination
       • What types of interventions could reduce this risk?
     • How could nanotechnology be used in food packaging?
   • Dehydration
   • Ubiquity in Environment
     • Produce Contamination
     • Animal contaminatino
   • Do certain stresses cause a more resilient organism?
     • Sporadic vs. endogenous organisms in food processing plants?

2. Infectious Dose

   • Widely Variable
     • Number of cells consumed
     • Immunological state of person
     • What role does our microbiota play here?
       • LAB and Bacteriocins
   • How does composition of food effect virulence?

3. Host Adapted

   • Gene Cluster
     • Listeriolysin O
       • Lysis of macrophage vacuole
         • Cytosol Replication
       • Hemolysin Activity
     • Internalin A/B
       • Invade epithelial cells
       • Zipper Mechanism
       • Invade host macrophage
     • PI-PLC
       • Role in vacuole escape
       • Lecithinase activity
     • Act A
       • Actin Polymerization
         • Cytosol movement
           • Cell-to-cell spread
             • Evade cellular immunity
     • Upregulated in host body temperatures (37C)
   • What role have other pathogens played for acquired virulence?
     • Comparative analysis of non-pathogenic Listeria spp. and Listeria monocytogenes
     • What do novel genes tell us about origin?
   • Carried through bloodstream
     • Sepsis
     • Perinatal Infection
     • Meningitits
     • Liver
       • Infection clears
   • 13 total L. monocytogenes serovars
     • 95% of Listeriosis cases are caused by only four serovars
       • What differences are there among L. monocytogenes serovars that make ones more virulent than others?
         • Topic chosen for further investigation and research grant proposal