Cholera, Campylobacter, Helicobacter Flashcards Preview

Microbio 2 > Cholera, Campylobacter, Helicobacter > Flashcards

Flashcards in Cholera, Campylobacter, Helicobacter Deck (36):
1

vibrio cholerae

causes cholera

motile gram negative fermenter, comma shape, polar flagellum

2

what strain of v. cholerae cause epidemics

O1- 2 types- classical and hemolytic (responsible for all cholera in the last decade)

3

what effect does acid have on v. cholerae?

inactivates some but not all

4

how does v. cholerae infect?

enters small bowel and bind to epithelium

uses toxin coregulated pilus- causes agglutination w other bacteria

5

cholera toxin

endocytosed into epithelium- binds to GM1 ganglioside

neurominidase is an enzyme that modifies the host glycosugars to make better binding sites

stimulates cAMP causing massive fluid loss

6

how does cAMP cause fluid loss?

activates CFTR

villus cells- decreased NaCl absorpotion

secretory cells- increased Cl and HO3 secretion

7

cholera symptoms

painless, odorless profuse water diarrhea (rice water stool)

isotonic volume loss, dehydration, H2O

8

cholera treatment

rehydration

antibiotics can reduce duration from 5-10 to 1-3 days

doxycycline or azithromycin (children/pregos)

9

where is cholera a problem

associated w/ poverty and inadequate sanitation

endemic in south america, africa, south central/south east asia

currently a pandemic

10

what is the cause of the recent endemic in south america?

aid workers coming for relief of haiti earth quake brought from nepal

11

how is cholera generally contracted?

contaminated water, shellfish, seafood, rice

12

cholera vaccine

both inactive and live

inactivated- only 70% effective, not recommended for travel

live- unproven in field, only critical trials

13

what season causes cholera outbreaks

rainy seasons- spring and fall

14

vibrio paraemolyticus

invasive gastroeneteritis from contaminated shellfish

15

vibrio vulnificus

infections in wounds from contaminated shellfish/seawater in people w/ liver disease

16

what media should be used to isolate cholera

TCBS- high in salt, high in bile salts

cholera turn greenish d/t thiosulfate

17

campylobacter morphology

gram negative rod, curved

18

where does campylobacter infect?

contaminated food and water. infects small and large bowel and causes invasive inflammation

rarely enters the bacteremia

19

campylobacter epidemiology

zoonotic- transmitted from animals, especially poultry. human to human is rare

peak in summer and early fall

most common cause of diarrhea in the world

20

campylobacter is microaerophilic

ok

21

campylobacter incubation period

3-5 days

22

symptoms of campylobacter

prodrome fever, malaise, headache

then

abdominal pain and diarrhea lasting a week

23

guillaim-barre syndrome

1/1000 people develop autoimmunity to their own nerves

24

campylobacter infectious dose

500

25

campylobacter virulence factor

cytolethal distending toxin released w/in mucosal factor.

26

campylobacter treatment

supportive

erythromycin or ciprolaxacin

27

campylobacter vaccine

none

28

helicobacter pylori morpholgy

gram negative, spiral shaped

29

where does helicobacter live in humans

stomach and duodenum. lives in the mucus lining

30

helicobacter virulence factors

urease- converts uera into bicarbonate and ammonia, which are both basic

adhesins- binds to lipids and carbs to adhere to epithelium (BabA- lewis b antigen)

CagA- injected into cells and disrupt cytoskeleton, signaling, polarity, etc.

VacA- damages epithelial lining

31

helicobacter pathogenesis

host sends immune response. cant penetrate mucus, die, and relase damaging free radicals- causes ulcers

also causes gastric cancer

32

how does helicobacter spread?

orally- fecal. organism present in 50% of the world

33

helicobacter infectious dose

not known for huamns

34

helicobacter diagnosis

radiolabeled urea test
stool culture
seroconversion
PCR
endoscopy

35

helicobacter treatment

bismuth, metronidazole, tetracycline

36

helicobacter vaccine

none