Flashcards in 11,12 - Microorganisms in Disease Deck (15):
the degree to which a micro-organism is able to cause disease
LD/ID50 stands for
Infectivity - how?
Host cell surface receptor
Facilitation of adhesion
Interference with host defence mechanisms
Facilitation of invasion
Modulation of the host cytokine resopnses
Namely, adhesins, aggressins, interferins, modulins
What are endotoxins?
Components of gram--ve bacterial cell wall: E.Coli, neisseria meningitidis
released from dmged/dead cells
Active component is lipopolysaccharide
Binds to number of host cell receptors inducing range of uncontrolled host responses
Host response to endotoxins
What is SIRS?
Uncontrolled T-lymphocyte response: cytokines (TNF-a, y-IFN, IL-1); fever, rigors, tachycardia, collapse --> cardiac/renal failure
Uncontrolled clotting cascade = DIC, clotting factor depletion + bleeding tendency
Uncontrolled complement activation
If a shock response is to increase permeability etc why do we get vasoconstriction?
Leakage of protein, fluid and plasma into tissues causes pathological compensatory vasoconstriction
protein produced by living bacteria - quite specific effect on host
Botulism - clinical presentation
Death - via resp. failure
What is the toxin produced by tetanus?
Produced on spore germination, binds to nerve synapses and inhibits neuro-trans
Causes death by resp. paralysis
what causes scarlet fever?
What does strep pyogenes do?
has virulence factors that promote connective tissue breakdown and invasion
Strep. pyogenes syndromes
Strep sore throat