Chapter 15 Flashcards
Pathogenicity
The ability to cause disease
Virulence
The degree of pathogenicity
Portals of entry (name 3)
- Mucous membranes - Skin - Parenteral route
Parenteral route
Deposited directly into tissues when barriers are penetrated
Most pathogens have a preferred _______ __ _____.
portal of entry
ID50
Infectious Dose for 50% of a sample population
Measures virulence of a microbe
LD50
Lethal Dose for 50 % of a sample population
Measures potency of a toxin
Almost all pathogens attach to host tissues in a process called ________
adherence (adhesion)
Adhesions (_____) on pathogen bind to _______ on host cells. Name two examples.
(ligands)
receptors
- Glycocalyx
- Fimbriae
After adherence microbes form ______
biofilms
Capsules: Glycocalyx around cell walls. What does this impair? Examples?
Impair phagocytosis
Streptococcus pneumoniae - pnuemonia
Haemophilus influenzae - pneumonia and meningitis
Bacillus anthracis - anthrax
Yersinia pestis - plague
M protein
Cell wall component; resists phagocytosis
Example: streptococcus pyogenes
Opa protein
Cell wall component; allows attachment to host cells
Example: neisseria gonorrhoeae
Waxy lipid
Cell wall component; (mycolic acid) resists digestion
(mycobacterium tuberculosis)
Coagulases
Coagulate fibrinogen
Kinases
Digest fibrin clots
Hyaluronidase
Digests polysaccharides that hold cells together
Collagenase
Breaks down collagen
IgA proteases
Destroy destroy IgA antibodies
Antigenic Variation
Pathogens alter surface antigens (and antibodies are rendered ineffective)
Invasions
Surface proteins produced by bacteria that rearrange actin filaments of the cytoskeleton (cause membrane ruffling)