Microbial Pathogenicity Flashcards
What is a pathogen
An organism capable of causing a disease
What is a commensal
An organism that is part of the Normal flora
What is pathogenicity
The ability to cause disease
What is virulence
The ability to cause severe disease
Describe the life cycle of a parasite
- enter
- attach
- colonise
- evade host immunity
- produce harmful proteins
- disseminate
- release from host
What are microorganisms
Agents that cause infectious diseases
What are microorganisms divided into
- bacteria
- fungi
- viruses
-prions - parasites
What is colonisation
When microbes find a new host and start to multiply
What is normal flora
A balance can develop between colonised microbes and humans this will lead to normal flora
What is an enpdogenous infection
When the source of microbe is the patients own flora
What is an exogenous infection
If source of a microbe is flora from outside the patients body
Describe Koch postulates (the germ theory of disease)
- a microbe must be present in every cause of the disease
- the microbe must be isolated from the diseased host and grown in pure culture
- the disease must be reproduced when a pure culture is introduced into a susceptible host
- the microbe must be recovered from an experimentally infected host
Describe Uniary Tract Infections
- about 50% of women will have one at some point in their lifespan
- colonise from faeces or perineal regions
What is the main host protection from utis
Main defence is flushing action of urine, bacteria produce specialised adhesive structures so they do not get flushed out
What is the difference between endo and exo toxins
- endotoxins are lipopolysaccharide exotoxins are proteins
- endotoxins are part of the outer membrane and exotoxins are extracellular, diffusible
- they are both antigenic
