medical microbiology presentation's notes

Vibro colria

1. Presentation topic Molecular mechanism of Pathogenesis

2. INTRODUCTION Owais Jehan Torwarsak , Buner 3 rd Semester Microbiology University of Swat [email protected]

3. Steps involved in the Pathogenicity Transmission Adhesion Colonization Invasion Survival in the host Tissue injury

4. Transmission Pathogens can invade the body through multiple pathways, including the respiratory system, digestive tract, urinary system, or reproductive organs. There are multiple transmission modes through which pathogens can transmit from an infected individual to a healthy one. It includes direct, indirect and vector borne transmission etc.

5. 2. Adhesion For bacteria, establishing a strong attachment is a vital first step before they can colonize and invade host tissues. Adhesion plays a critical role in helping bacteria resist the body's natural defense mechanisms. Such as the gut's peristaltic movements and the cleansing effects of mucus, saliva, and urine, which work to wash away bacteria that fail to attach.

6. 3. Colonization After successful adhesion to the host cell. Bacteria want to stable their position so they start colonization. Colonization is the process through a bacteria increase their population or numbers.

7. 4. Invasion Invasion refers to the process where pathogens breach host cells and tissues, extending beyond just the skin and mucous membranes. This complex interaction is driven by a variety of specialized molecules, commonly known as invasins . Invasins may be bacterial proteins located on the surface or secreted into the environment, which specifically bind to host cell receptors to facilitate entry.

8. 5. Survival in the host Pathogen must resist host defense mechanisms like phagocytosis, complement system and antibodies. Capsule formation → inhibits phagocytosis. Antigenic variation → changes surface proteins to avoid recognition. Secretion of immune-modulating proteins → HIV destroys CD4+ T-cells. Biofilm formation → bacteria in biofilms resist antibiotics and immune attack.

9. 6. Tissue injury Bacterial infections lead to tissue damage through several key pathways, including: Toxins →Toxins are poisonous substances produced by pathogens that damage host cells or trigger harmful immune responses. There are two types of toxins produced by the bacteria. Endotoxins Exotoxins

10. Exotoxins vs Endotoxins

11. Q&A Session

12. Thank You for your Attentions