Bacterial Virulence
Upcoming SlideShare
Loading in...5
×
 

Bacterial Virulence

on

  • 8,797 views

 

Statistics

Views

Total Views
8,797
Views on SlideShare
8,797
Embed Views
0

Actions

Likes
2
Downloads
219
Comments
0

0 Embeds 0

No embeds

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

CC Attribution-NonCommercial LicenseCC Attribution-NonCommercial License

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

Bacterial Virulence Bacterial Virulence Presentation Transcript

  • Bacterial Virulence Factors Prof. Nesrene Salah Omar
  • Objectives• Microbial Mechanisms of Pathogenic• Microbes and humans• Virulence factors• Host - parasite Interaction• Bacterial Virulence Factors
  • Microbial Mechanisms of Pathogenic
  • Microbes and humans Very few microbes are always pathogenic Many microbes arepotentially pathogenicMost microbes arenever pathogenic
  • Host - parasite InteractionEukaryotic Cell Pili or adhesins Prokaryotic Cell Intracellular Control of virulence factors: Virulent Bacteria (Pilin, capsule, invasins, toxins etc) Adherence blockers Receptor
  • Prokaryotic and Eukaryotic InteractionsEukaryotic Cell Pili or adhesins Prokaryotic Cell Intracellular Control of virulence factors: Virulent Bacteria (Pilin, capsule, invasins, toxins etc) Adherence blockers Receptor COLONIZATION
  • Prokaryotic and Eukaryotic InteractionsEukaryotic Cell Pili or adhesins Prokaryotic Cell Intracellular Control of virulence factors: Virulent Bacteria (Pilin, capsule, invasins, toxins etc) Adherence blockers Receptor COLONIZATION INVASION
  • VirulenceThe ability of an agent of infection to produce disease.The virulence of a microorganism is a measure of the severity of the disease it causes.
  • Bacterial Virulence Factors
  • Virulence factors help bacteria• invade the host• cause disease• evade host defenses.Include:7. Attachment (via adhesins)8. Colonization9. Invasiveness10. Toxins & Enzymes11. Inhibition of Phagocytosis
  • (Attachment (via adhesins-1They allow bacteria to bind to host cells : Cilia - motion• fimbriae• some bacterial cell walls• capsulesThese adhesins bind to specific epithelium receptors or they are able to maintain even closer contact. Flagellum - motion
  • A Cell Wall –Flagellum - protection,motion invasion, evasion Cell Parts D B Ribosome – production of Cilia - motion toxins/attachment proteins on cell wall
  • 2-Colonization• The Ability to Adhere to Host Cells and Resist Physical Removal or• the establishment of the pathogen at the appropriate portal of entry.• Pathogens usually colonize host tissues that are in contact with the external environment.
  • Virulence Factors that Promote Bacterial Colonization:3. Using Pili (fimbriae) to Adhere to Host Cells4. Using Adhesins to Adhere to Host Cells5. Using Biofilms to Adhere to Host Cells
  • Invasiveness-3• the ability of a pathogen to invade tissues.• Invasiveness encompasses(1) mechanisms for colonization (adherence and initial multiplication),(2) production of extracellular substances ("invasins"), that promote the immediate invasion of tissues(3) ability to bypass or overcome host defense mechanisms which facilitate the actual invasive process.
  • Invasiveness• Hyaluronidase• Coagulase• Streptokinase (dissolves Clots)
  • 4-Toxins &EnzymesToxins• They are products of a pathogen that destroy/ damage/• inactivate one or more vital component of the host.• Classes of toxinsNeurotoxinsEnterotoxinsCytotoxins
  • EnzymesExcretion of certain pathogens to assist them in establishing infection and producing a disease.There are virulence determinant enzymes that dissolve the glue between cells, thus allowing the bacteria to spread rapidly through the tissue.
  • -5Inhibition of PhagocytosisPhagocytosis
  • Inhibition of Phagocytosis• Ability of Pathogens to Avoid or Overcome Phagocytes• Avoiding Contact with Phagocytes• Inhibition of Phagocytic Engulfment• Survival Inside of Cells
  • SummaryVirulence factors
  • Thank you