Lecture 6: Commensalism Vs Pathogenicity Flashcards
How many organisms benefit in mutualism/symbiosis? How many are harmed?
2 benefit
none harmed
How many organisms benefit in commensalism? How many are harmed?
1 benefits
none harmed
2nd neutral
How many organisms benefit in parasitism/pathogenesis? How many are harmed?
1 benefits
1 is harmed
Where is S. epidermatis commensal?
Skin
Where is C. albicans commensal?
Skin
Where are staph and strep commensal?
Throat
Where are coliforms commensal?
Gut
What is a symbiotic bacterium in the vagina?
Lactobacillus
What type of bacteria are symbiotic in the gut?
Nutrient-generating
Commensals participate in what kind of resistance?
Colonization resistance
Colonization resistance is an important element of what type of immunity?
innate immunity
A nonpathogen has a ____ LD50 and a _____ ID50
high
high
need lots to infect/kill
An opportunistic pathogen has a _____ LD50 and a _____ ID50
high LD50 - need lots to be lethal
mid-low ID50 - need less to infect
An opportunistic pathogen is unlikely to cause disease, unless host is ________.
Debilitated
A pathogen has _______ pathogenicity, ______ LD50, and ______ ID50
high pathogenicity
mid-low LD50
low ID50
What are defined as genes found experimentally necessary for pathogens to produce disease?
Virulence factors
What are the 5 specific categories of virulence factors (6 is other)?
Survive Extreme Environments Adhesion Immune evasion Host cell takeover Poisoning host
Where are virulence factors usually found within the bacterial genome?
Plasmids (accessory DNA)
How are virulence factors usually regulated?
Pathogenicity Island
What are the two common methods for transferring virulence factors?
horizontal transfer (plasmids) phage infection
What are defined as polypeptides secreted form pathogen or injected into host cell by TSS3, as they relate to virulence factors?
Exotoxins
What are three specific sources of profound toxicity from virulence factors?
Superantigenicity
interference with signal transduction
depolymerization of actin
A toxin which is inactivated chemically or with heat is called what? What can it be used for?
Toxoid
Used for vaccines
In an exotoxin with A-B subunit structure, what does each subunit do?
A has toxic activity
B delivers a to target site
