Definition: Infection
Process of establishing a relationship between microbe and host- may/may not cause disease
Definition: Infectious disease types?
Disease caused by an infection with a microbeCommunicable - transmitted patient to patient Non-communicable - not transmitted
Definition: Pathogenicity Frank vs opportunistic
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Definition:Virulence low vs high
Relative capacity to damage a host; measure of pathogenicity (ability to cause disease)Few microbes needed for disease = high virulence Many microbes needed for disease = low virulence
Koch’s Postulates
Stages of pathogenesis of ID
Typical stage in pathogenesis: Encounter
1st stageHow the agent meets the host.
Give an example of microbial ‘spreading factors’ through tissues
during 3rd stageHyaluronidase, elastase, collagenase
how can coagulase inhibit spread of microbes.
coagulase: inhibits spread of microbes because it lays down fibrin to “wall off” and localize infection
Typical stage in pathogenesis: damage
5th stagehow tissue damage is cause by the agent and/or the host responseare virulence factors present?
Typical stage in pathogenesis: outcome
6th stagedoes the microbial agent or the host win the battle, or do they learn to coexist?
Innate vs. Adaptive defense against infections
Innate: Immediate response Adaptive: Defends against future recurrences
Things that affect composition of microbiome
Importance of microbiome
If growth rate in vivo is slower than in vitro, what does that mean?
host defense is aiding to prevent infection
Skin normal flora
Staphylococci Enteric bacilli Corynebacteria Propionobacterium acnes
Large intestine normal flora
Micrococcus streptococci (enterococcus) Lactobacilli Enteric bacilli Clostridia Pseudomonas
Vaginal normal flora
Streptococci Lactobacilli Bacteroides Mycoplasma
What does the disease paradigm of pathogenesis mean?
Certain types of bacteria will result in very specific disease
Using disease paradigm of pathogenesis, what causes Cholera?
A toxin-mediated disease
Using disease paradigm of pathogenesis, what causes Pneumococcal pneumonia
acute inflammation caused by invasive, extracellular bacteria
Using disease paradigm of pathogenesis, what causes Tuberculosis
infection by a facultative intracellular bacterium
What causes Rheumatic fever
pathology mediated by an immune response