bacterial virulence factors

Question 1

refers to how harmful a pathogen is to the host
- helps the pathogen succeed in infection

Answer 1

virulence

Question 2

how are virulence factors determined?

Answer 2

genetic makeup of a pathogen; DNA/RNA

Question 3

where are virulence factors found?

Answer 3

plasmids –> extra outside DNA

Question 4

more virulent =

Answer 4

more dangerous/pathogenic

Question 5

different genetic variants of the same microorganism can be

Answer 5

beneficial (lower virulence factors) or pathogenic or neutral

Question 6

beneficial e. coli is found

Answer 6

k-12
found in lower intestines –> produces vitamin K and prevents colonization of gut w/ harmful bacteria

Question 7

pathogenic e. coli is found

Answer 7

0157: h7
cause serious food poisoning

Question 8

how disease is caused in a host

Answer 8

pathogenesis

Question 9

virulence factors are required for a pathogen to

Answer 9

persist in the patient
cause disease
escape/defeat host defenses

Question 10

will cause disease if given opportunity, depends on location change in the body

Answer 10

opportunistic pathogen (ex: e. coli k-12)

Question 11

will always cause disease; not found naturally in the body

Answer 11

primary pathogen

Question 12

recognized by immune cells; trigger immune response

Answer 12

antigenic

Question 13

antigenic structures in e. coli

Answer 13

endotoxin production
capsule
proteins on flagella

Question 14

structures that produce disease in gi tract

Answer 14

invasive properties
produce toxins

Question 15

non pathogenic

Answer 15

no virulence factors (no proteins, capsule, extra plasmids)

Question 16

pathogenic

Answer 16

many virulence factors

Question 17

categories of pathogenic e. coli

Answer 17

1) enterotoxigenic e. coli (ETEC)
2) enterpathogenic e. coli (EPEC)
3) enteroinvasive e. coli (EIEC)
4) enterohemorragic e. coli (EHEC) - 0157/h7

Question 18

folds; increase surface area of intestinal tissue; absorption of nutrients

Answer 18

villus

Question 19

cause of traveler’s diarrhea and major cause of diarrheal disease in developing countries

Answer 19

enterotoxigenic e. coli (ETEC)

Question 20

how is etec transmitted

Answer 20

food or water contaminated with animal or human feces

Question 21

how does etec work?

Answer 21

produces enterotoxins that stimulate lining of intestines –> causes secretion of excessive fluid; watery diarrhea and cramps

Question 22

leading cause of infant diarrhea worldwide, high rate of morbidity and mortality, especially in developing country

self-eliminating in healthy populations

Answer 22

enteropathogenic e. coli (epec)

Question 23

how does epec work?

Answer 23

no toxin production
produce lesions on the small intestine, which form pedestals and destroy microvilli

Question 24

how does epec form pedestals

Answer 24

recruits actin from host cell

Question 25

what happens when epec destroys microvili?

Answer 25

body rejects food and flushes it out quickly (limits nutrient absorption) --> can lead to dehydration, malnourishment, and deaht

Question 26

uses adhesin protein to bind to and enter intestinal cells hijacks actin filaments from host cells and rearranges them to form "actin comet tail" allows propulsion into nearby cells --> mechanical damage no toxin production

Answer 26

enteroinvasive e. coli (eiec)

Question 27

what does eiec cause?

Answer 27

diarrhea, colitis, dysentery

Question 28

causes disease due to shiga toxin

Answer 28

enterohemorrhagic e. coli (ehec)

Question 29

what does shiga toxin do

Answer 29

causes clots in blood vessels (kidneys) hemolytic uremic syndrome (HUS) produce endotoxins upon death live in the guts of ruminant animals