Principles of pathogenesis Flashcards
What are kochs postulates to identify a causative agent of a disease?
The pathogen must be present in every case of the disease
The pathogen must be able to be isolated from the host and grown in culture
Specific disease is recreated when this pathogen is introduced into a healthy host
Pathogen is recoverable experimentally from the infected host
What is bacterial virulence and what is a virulence factor?
Virulence is what differentiates pathogens from commensals
An example of a cirulence factor is proteinaceous exotoxins, these can elicit the features of bacterial infection when injected as pure proteins.
What are the main steps in a succesful infection?
Sex - transfer virulence factors by conjugation Sense environment Swim to site of infection Stick to site of infection Scavenge nutrients Survive stress Stealth Strike back Subvert Spread Scatter
What are the main ways that bacteria can switch their virulence factors on and off?
changes in DNA sequence such as gene amplification
Transcriptional regulation through mRNA folding
Translational and post translational regulation
