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Flashcards in IDMM Week 1 PBL Deck (38):
1

List the viruses that cause enteric infections

Rotavirus
Enteric adenovirus
Norwalk virus

2

What type of enteric infection do viruses cause

self limited infectious diarrhea

3

Transmission of rotavirus

children under 6
contaminated water
fecal oral

4

Pathogenic features of rotavirus

destroy mature epithelial cells in the middle and upper villi--watery diarrhea is due to MALABSORPTION

5

transmission of enteric adenovirus

young children and infants
sporadic

6

Pathogenic features of enteric adenovirus

self limited infectious diarrhea

7

Norwalk virus transmission

young and old
fecal oral

8

Pathogenic features of norwalk virus

epidemic gastroenteritus with diarrhea, nausea, vomiting

9

List bacteria that cause enteric infections

enterotoxigenic E. Coli
Campylobacter jejuni
Yersinia enterocolita
Shigella
Enteropathogenic E. coli
Salmonella
C. Difficile
Vibrio cholerae

10

Transmission of ETEC

travellers diarrhea
food and water borne

11

pathogenic features of ETEC

watery diarrhea

heat labile toxin activates AC-->increases concentration of cAMP

heat stable toxin increases [cGMP]-->resultsin reduced Na+ absorption in villus cells and increased CL- secretion in crypt cells

12

Transmission of campylobacter jejuni

mainly kids
contaminated food and water
zoonotic

13

Pathogenic features from campylobacter jejuni

gastritis, enterocolitis, septicemia

causes BLOODY diarrhea and FEVER

cholera-like toxins, invasion (leading to inflammation), translocation into lamina propria and mesenteric lymph nodes

Guillain-barre syndrome

14

Yersinia enterocolita transmission

mainly kids
contaminated food and water

15

Yersinia enterocolita pathogenic features

-RUQ pain
-BLOODY, mucoid diarrhea
-pseudoappendicities, mesenteric adenitis syndrome (Peyer's patches)
-arthritis, ERYTHEMA NODOSUM

HA enterotixin--like E. Coli: invasion into intestinal wall, regional lymph nodes and blood

16-72 hour incubation

16

Shigella transmission

fecal oral
contaminated food and water

17

Shigella pathogenic featuers

-DYSENTERY
-invasion, SHIGA TOXIN (causes hemorrhage, inhibits protein synthesis), actin rockets for cell-cell invasion

18

Enteropathogenic E. Coli transmission

children--nursery school outbreaks

19

Enteropathogenic E. Coli pathogenic features

-watery diarrhea
-initial binding is by bundle-forming pilus
-binding activates phospholipase C trhough Hp-90-->increase IP3 and Ca2+ which causes actin polymerization immediately beneath the organism-->effacement of microvilli
-intimate contact is mediated by a number of proteins )intimin)
-organism sits on the flat pedestal created by the altered cytoskeleton
-change in cell architecture causes direct damage, excess water, leading to diarrhea
-attaching and effacing lesions

20

salmonella transmission

food and water borne
human and animal reservoirs

21

salmonella pathogenic features

S. typhi - typhoid fever (including intestinal bleeding)

Gastroenteritis
sepsis

22

C. difficile transmission

hospital acquired
antibiotic associated

23

C. difficile pathogenic features

pseudomembrane
enterotoxin--disrupts membrane integrity
cytotoxin--cells lose filaments and lyse
NON INVASIVE

24

Vibrio cholerae transmission

pandemic
epidemic

25

vibrio cholerae pathogenic features

severe watery diarrhea due to cholera toxin

26

parasites associated with enteric infections

giardia lamblia
entamoeba histolytica

27

transmission of giardia

travellers diarrhea
contaminated drinking water

28

pathogenic features of giardia

NO enterotoxins
NO invasion
IgA proteases, sucker disc to adhere

cause diarrhea due to MALABSORPTION

FROTHY, FATTY stool

29

transmission of entamoeba histolytica

large reservoir of asymptomatic carriers

fecal oral

sexual transmission (anal)

contaminated food and water

30

entamoeba histolytica pathogenic features

-BLOODY diarrhea
-FEVER
-intestinal pain

attach to colonic epithelium, lyse colonic epithelial cells, invade bowel wall

contain cysteine proteases, channel forming protein for BORING HOLES into plasma membranes

31

Methods for parasite detection

special formalin preparation
O&P

32

what tests do you need special requests for?

O&P
viruses
non-routine bacteria (i.e C. diff and shiga toxin)

33

Do you use gram staining in most GI infection diagnosis?

No because already a large amount of bacteria in GI under normal circumstances

34

Why might antibiotics be contraindicated in some enteric infections?

they may lyse the bacteria and release large amounts of endotoxin or exotoxin which exacerbates the symptoms ie with EHEC

35

Which enteric infections are indicated for antibiotics?

Shigellosis
Typhoid fever
Cholera

36

List infection control measures to prevent the spread of enteric pathogens to others

-adequate hand washing
-proper disposal of fecal matter
-maintain a clean water supply
-stay at home if sick
-dont share foodstuffs
-dont share dishware and eating utensils
-wash and cook foodstuffs thoroughly
-proper transport and storage of food

37

Public health measures taken against food-borne illness

-food safe education program
-ongoing surveillance programs
-mandatory reporting programs (shigella, e. coli, listeria, clostridium botulinum, salmonella)

38

What is the public health investigation that follows the outbreak of a food-borne illess

1. initial assessment--ID causative agent, investigate its source
2. risk assessment--determine resources required
3. public notices--recall product if necessary--prevent future outbreak
4. post-outbreak education and establishment of new guidelines if required