lecture 33 - microbial pathogenicity Flashcards
What are the 5 key types of microbial pathogen?
Viruses, fungi, protozoa, Helminths, bacteria
What is the principle of Koch’s postulate?
Specific pathogens cause specific diseases
What is microbial pathogenesis?
A process in which pathogens infect cells, leading to damage and disease.
What are the 4 stage of microbial pathogenesis?
Adherence to host cells, invasion of host tissues, replication within host, damage & disease
What bacterial virulence factors aid in the adherence stage of pathogenesis?
Adhesins, e.g. fimbriae
What bacterial virulence factors aid in the invasion stage of pathogenesis?
Flagella provide motility, Internalin-related proteins help pathogen ‘burrow in’
What bacterial virulence factors aid in the replication stage of pathogenesis?
Siderophores bind iron, and capsules resist phagocytosis
What bacterial virulence factors aid in the damage/disease stage of pathogenesis?
Endotoxins and exotoxins
What are endotoxins?
A virulence factor - Lipopolysaccharides found in the outer membrane of gram-negative bacteria that elicit a strong immune response.
What immune responses are elicited by endotoxins?
Fever, inflammation, shock, blood clotting
What are exotoxins?
Proteins that are released from bacterial cells and have a toxic effect on the host’s tissues.
What is the difference between bacterial endotoxins and exotoxins?
Endotoxins are membrane-bound compounds that elicit inflammation, while Exotoxins are proteins released from bacterial cells that have the potential to act distant to the site of infection.
What are the 3 types of bacterial exotoxins?
Cytotoxins, neurotoxins, enterotoxins
What are cytotoxins?
exotoxins released by bacteria that harm cells, e.g. via lysis
What are bacterial neurotoxins?
Exotoxins released by bacteria that destroy nerve tissue. e.g. inhibiting ACh release causing paralysis.
