Microbial pathogenicity - 32 Flashcards
What are the 6 important microbial pathogens
Viruses Fungi Prions Protozoa Helminths Bacteria
What is an example of a virus
Influenza virus (H1N1) Single stranded RNA and envelope
What is an example of a Fungi
Ring worm. (Trichophyton spp.)
What is an example of a Prion
Kuru (laughing disease - effects the brain)
What is an example of a protozoa
Malaria parasites (Plasmodium spp.)
What is an example of a helmets
Hook worm (Ancylostoma duodenale)
What is an example of a bacteria
Gram-positive, endospore-forming, rod-shaped bacterium
What are Koch’s postulates
Pathogen must be present in every infected individual
Sample from microorganism can be grown in pure culture
Sample or pure culture causes same disease when injected into healthy host
Microorganisms can be recovered from injected host
What are the exceptions to Koch’s postulates
When microbes can’t be cultured
When pathogens can be found in healthy subjects
What are the stages of microbial pathogenesis
1 - Adheres to cell
2 - Invasion of host tissue
3 - Replicates within host tissue (colonization)
4 - Disease causes damage to host (pathology)
Describe factors of stage 1 of pathogenesis and an example of when used
Adherence to host cell - Fimbriae (hair like structures) Sticky, helps bind to host cell.
Neisseria gonorrhoeae
Describe factors of stage 2 of pathogenesis and an example of when used
Invasion of host tissue.
Motility - Ability to move through mucus (flagella) - Helicobacter pylori
Internalin-related proteins (InIB) dissolve or attach better to cells - Listeria monocytogenes
Describe factors of stage 3 of pathogenesis and an example of when used
Replication within host tissue.
Siderophores find iron and enzymes break it down (eat) - Yersiniabactin pestis
Capsules. Hide bacteria from phagocytes - streptococcus pneumoniae
Describe factors of stage 4 of pathogenesis and an example of when used
Disease causes damage to host tissue.
Endotoxins - Cause inflammation
Exotoxins - Can be fatal
Describe endotoxins
Lipopolysaccharides (LPS) found in outer membrane of Gram-negative bacteria
