Flashcards in 19. Microbial Interactions/Pathogenicity Deck (30)
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1
What is virulence?
The intensity/degree of pathogenicity
2
What is pathogenicity?
The ability to cause disease
3
What is symbiosis?
Close association of 2+ dissimilar organisms
Can be positive or negative
4
3 examples of positive symbiosis?
Mutualism
Cooperation
Commensalism
5
4 examples of negative symbiosis?
Predation
Parasitism
Amensalism
Competition
6
What is amphibiosis
one species can be helpful/harmful/or both simultaneously depending on the circumstances
7
Different between mutualism and cooperation?
Both species benefit, but in mutualism they DEPEND on each other for survival => cooperation they do not
8
What is commensalism
One species benefits
Other unaffected
9
What is amensalism?
One species kills the other
10
What is competition?
One species outcompetes the other for resources
11
Example of mutualism?
Termites and Trichonympha
Tric break down cellulose, turns it to CO2 and H2
12
Microbiologists refer to parasites as what 2 things?
Protozoans (plasmodium)
Worms (tapeworms)
13
What 4 things determine virulence?
Infectivity, invasiveness, adhesiveness, toxigenicity
14
What is a vector?
Living org that transfers an infective agent between hosts
e.g. mosquitoes and malaria
15
What is a vehicle?
Inanimate material that can transmit pathogens
e.g. surgical equipment
16
What is a carrier?
Infected individual who is a potential source of infection for others
17
What are zoonoses?
Infectious diseases that can be transmitted from animals to humans
18
2 examples of zoonoses?
Anthrax (from diseased animal flesh)
Tuberculosis (from contaminated cow's milk)
19
Example of a skin commensal?
Staphylococcus epidermis
20
Different between resident and transient skin commensals?
Resident = grow on skin
Transient = temporarily on skin
21
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)
22
Example of commensalism in human microbiome?
Skin commensals on our skin
23
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
24
4 factors that affect the outcome between host and pathogen?
Inoculum size
Location
Health of host
Virulence of pathogen
25
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
26
What is tropism?
Location of the host that will support growth of pathogen
27
Example of an endotoxin? How?
LPS
Initially attached to bacterium, but when it replicates/lyses => LPS released
28
What is an endotoxin?
Cell-associated toxin
29
Example of an exotoxin?
Botulinum toxin
30
