Flashcards in 19. Microbial Interactions/Pathogenicity Deck (30)
What is virulence?
The intensity/degree of pathogenicity
What is pathogenicity?
The ability to cause disease
What is symbiosis?
Close association of 2+ dissimilar organisms
Can be positive or negative
3 examples of positive symbiosis?
4 examples of negative symbiosis?
What is amphibiosis
one species can be helpful/harmful/or both simultaneously depending on the circumstances
Different between mutualism and cooperation?
Both species benefit, but in mutualism they DEPEND on each other for survival => cooperation they do not
What is commensalism
One species benefits
What is amensalism?
One species kills the other
What is competition?
One species outcompetes the other for resources
Example of mutualism?
Termites and Trichonympha
Tric break down cellulose, turns it to CO2 and H2
Microbiologists refer to parasites as what 2 things?
What 4 things determine virulence?
Infectivity, invasiveness, adhesiveness, toxigenicity
What is a vector?
Living org that transfers an infective agent between hosts
e.g. mosquitoes and malaria
What is a vehicle?
Inanimate material that can transmit pathogens
e.g. surgical equipment
What is a carrier?
Infected individual who is a potential source of infection for others
What are zoonoses?
Infectious diseases that can be transmitted from animals to humans
2 examples of zoonoses?
Anthrax (from diseased animal flesh)
Tuberculosis (from contaminated cow's milk)
Example of a skin commensal?
Different between resident and transient skin commensals?
Resident = grow on skin
Transient = temporarily on skin
6 ways we prevent skin commensals from invading our skin?
Keratinized skin layer
Low water activity (aw)
Skin constantly sloughed
Organic acids (low pH impedes microbial growth)
NaCl (sweat increases solute conc)
Lysozyme (cleaves bacterial NAG-NAM bonds in peptidoglycan)
Example of commensalism in human microbiome?
Skin commensals on our skin
7 steps a pathogen takes to cause an infectious disease?
1. Maintain a reservoir
2. Be transported to and enter a suitable host through a suitable route
3. Adhere to, colonize, invade host cells
4. Invade host defenses
5. Multiply and complete life cycle
6. Damage host
7. Leave the host
4 factors that affect the outcome between host and pathogen?
Health of host
Virulence of pathogen
How to test metabolic interdependence between termites and their associated protist (Trichonympha)?
Expose termites to hyperbaric oxygen
Inside the guy is anaerobic so the protist will die
Termite eventually survives but will ultimately starve since the protists in its gut are dead
What is tropism?
Location of the host that will support growth of pathogen
Example of an endotoxin? How?
Initially attached to bacterium, but when it replicates/lyses => LPS released
What is an endotoxin?
Example of an exotoxin?