pathology 17 (785-796): infectious enterocolitis

Question 1

what are the shape and stain of vibrio cholerae

Answer 1

comma-shaped, gram negative

Question 2

how is cholera primarily transmitted

Answer 2

contaminated drinking water

Question 3

what are needed for efficient bacterial colonization of V. cholerae

Answer 3

flagellar proteins

Question 4

what metalloproteinase is important for bacterial detachment and shedding in the stool with V. cholerae

Answer 4

hemagglutinin

Question 5

what does the B subunit of cholera toxin do

Answer 5

binds GM1 ganglioside on the surface of intestinal epithelial cells and is carried by retrograde transport to the ER

Question 6

describe the stools that are associated with V. cholerae

Answer 6

resembles rice water and are sometimes described as having a fishy odor

Question 7

what is the most common bacterial enteric pathogen in developed countries

Answer 7

campylobacter jejuni

Question 8

what are most infections by campylobacter jejune associated with

Answer 8

injection of improperly cooked chicken

Question 9

what are the 4 major properties that contribute to pathogenesis of campylobacter infection

Answer 9

motility, adherence, toxin production and invasion

Question 10

what patients are most susceptible to developing reactive arthritis as a result of campylobacter jejuni infection

Answer 10

those with HLA-B27

Question 11

describe the shape and staining of campylobacter

Answer 11

comma shaped, flagellated, gram-negative organisms

Question 12

describe shigella (stain)

Answer 12

gram negative unencapsulated, non-motile, facultative anaerobes

Question 13

why does shigella have an extremely low infectious dose

Answer 13

because it is resistant to the harsh acidic environment of the stomach

Question 14

what takes up shigella once it is in the intestine

Answer 14

M/microfold cells

Question 15

where are shigella infections most prominent

Answer 15

left colon

Question 16

what is the typical incubation period for shigella

Answer 16

up to 1 week

Question 17

describe the self-limiting disease caused by shigella

Answer 17

characterized by 1 week of diarrhea, fever and abdominal pain

Question 18

what do the transferred proteins involved with salmonella activate

Answer 18

host Rho GTPases, thereby triggering actin rearrangement and bacterial endocytosis allowing bacterial growth within endosomes

Question 19

what T cells are involved in limiting salmonella infection

Answer 19

Th1 and Th17

Question 20

what are the specialized bacterial proteins used by Yersinia to bind to host cell beta1 interns

Answer 20

adhesions

Question 21

what encodes the iron uptake system that mediated iron capture and support with yersinia

Answer 21

pathogenicity island

Question 22

where do yersinia infections preferentially involve

Answer 22

ileum, appendix and right colon

Question 23

what are the principle cause of travelers diarrhea

Answer 23

ETEC

Question 24

how does ETEC spread

Answer 24

contaminated water or food

Question 25

what are EIEC organisms most bacteriologically similar to

Answer 25

shigella

Question 26

what does EIEC cause

Answer 26

acute self-limited colitis

Question 27

what generally causes pseudomembranous colitis

Answer 27

C. difficile

Question 28

what does toxins released by C. difficile cause

Answer 28

ribosylation of small GTPases, such as Rho, and lead to disruption of epithelial cytoskeletal, tight junction barrier loss, cytokine release, and apoptosis

Question 29

what are the risk factors for C.difficile associated colitis

Answer 29

advanced age, hospitalization and antibiotic treatment

Question 30

what is the malabsorptive diarrhea of whipple disease due to

Answer 30

impaired lymphatic transport

Question 31

describe the genome of rotavirus

Answer 31

encapsulated virus with segmented, DS RNA genome

Question 32

who are most vulnerable to rotavirus

Answer 32

children between 6 months and 24 months of age

Question 33

what does rotavirus selectively infect and destroy

Answer 33

mature enterocytes in small intestine and villus surface is repopulated by immature secretory cells

Question 34

where do strongyloides mature into adult worms

Answer 34

intestine

Question 35

where do adult worms commonly reside with schistosomiasis

Answer 35

mesenteric veins

Question 36

what deficiency can D. datum cause

Answer 36

B12 deficiency and megaloblastic anemia because it competes with the host for dietary B12