Pathogenesis (lec 3) Flashcards
Colonization is?
Transiently/permanently established microbe
No interference
Infection is?
Colonization w/ tissue invasion and multiplication
(P) progress to disease
Disease is?
Abnormal fxn/structure
Host damage
Virulence is?
degree of pathology caused by pathogen
Koch’s Postulates?
Isolate/identify by growth in pure culture
Mullis’ Polymerase Chain Rxn?
Isolation/identification thru nucleic acid amplification (match gene sequence to known sequence)
Endogenous bacteria is?
Opportunistic, part of normal microbiota
e.g staph epidermis -> blood
Exogenous bacteria is?
Bacteria NOT part of normal microbiota,
introduced from outside body
Opportunistic (U) to compromised immune systems
Virulent/Strict pathogens
Always cause disease:
Damage/loss of tissue/organs,
Inflammatory response
e.g. m. tuberculosis, n. gonorrhoeae
Mechanism of Virulence: Metabolites?
tissue damaging by-products (acids, gases)
Mechanism of Virulence: Enzymes?
spreading factor:
- act locally or affect tissue matrices/intercellular spaces
- facilitate spread and growth of pathogen
Types of Virulence Enzymes? (4)
1) Hyaluronidase: attacks hyaluronic acid of CT
2) Collagenase: attacks collagen in mm, tendons, ligaments
3) Neuraminidase: attacks neu. acid (intercellular cement) of epithelial cells of intestinal mucosa
4) Strepto/Staphylokinase: prevents clotting (Fibrinolysins)
Mechanism of Virulence: Adhesion?
Bacterial ligand binds hosts’ receptor
(U) carb moieties of glycoproteins
Methods of adhesion?
Fimbrial/Pili
Afimbrial: proteins in cell envelope (glycocalyx)
Mechanism of Virulence: Toxins
Exotoxins?
Proteins from G+ and G-:
toxic by direct action
bind host receptors
secreted into extracellular fluid or a/w cell surface
