Cholera, Campylobacter, Helicobacter

Question 1

vibrio cholerae

Answer 1

causes cholera

motile gram negative fermenter, comma shape, polar flagellum

Question 2

what strain of v. cholerae cause epidemics

Answer 2

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

Question 3

what effect does acid have on v. cholerae?

Answer 3

inactivates some but not all

Question 4

how does v. cholerae infect?

Answer 4

enters small bowel and bind to epithelium

uses toxin coregulated pilus- causes agglutination w other bacteria

Question 5

cholera toxin

Answer 5

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

Question 6

how does cAMP cause fluid loss?

Answer 6

activates CFTR

villus cells- decreased NaCl absorpotion

secretory cells- increased Cl and HO3 secretion

Question 7

cholera symptoms

Answer 7

painless, odorless profuse water diarrhea (rice water stool)

isotonic volume loss, dehydration, H2O

Question 8

cholera treatment

Answer 8

rehydration

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

doxycycline or azithromycin (children/pregos)

Question 9

where is cholera a problem

Answer 9

associated w/ poverty and inadequate sanitation

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

currently a pandemic

Question 10

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

Answer 10

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

Question 11

how is cholera generally contracted?

Answer 11

contaminated water, shellfish, seafood, rice

Question 12

cholera vaccine

Answer 12

both inactive and live

inactivated- only 70% effective, not recommended for travel

live- unproven in field, only critical trials

Question 13

what season causes cholera outbreaks

Answer 13

rainy seasons- spring and fall

Question 14

vibrio paraemolyticus

Answer 14

invasive gastroeneteritis from contaminated shellfish

Question 15

vibrio vulnificus

Answer 15

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

Question 16

what media should be used to isolate cholera

Answer 16

TCBS- high in salt, high in bile salts

cholera turn greenish d/t thiosulfate

Question 17

campylobacter morphology

Answer 17

gram negative rod, curved

Question 18

where does campylobacter infect?

Answer 18

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

rarely enters the bacteremia

Question 19

campylobacter epidemiology

Answer 19

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

Question 20

campylobacter is microaerophilic

Answer 20

ok

Question 21

campylobacter incubation period

Answer 21

3-5 days

Question 22

symptoms of campylobacter

Answer 22

prodrome fever, malaise, headache

then

abdominal pain and diarrhea lasting a week

Question 23

guillaim-barre syndrome

Answer 23

1/1000 people develop autoimmunity to their own nerves

Question 24

campylobacter infectious dose

Answer 24

500

Question 25

campylobacter virulence factor

Answer 25

cytolethal distending toxin released w/in mucosal factor.

Question 26

campylobacter treatment

Answer 26

supportive

erythromycin or ciprolaxacin

Question 27

campylobacter vaccine

Answer 27

none

Question 28

helicobacter pylori morpholgy

Answer 28

gram negative, spiral shaped

Question 29

where does helicobacter live in humans

Answer 29

stomach and duodenum. lives in the mucus lining

Question 30

helicobacter virulence factors

Answer 30

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

Question 31

helicobacter pathogenesis

Answer 31

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

also causes gastric cancer

Question 32

how does helicobacter spread?

Answer 32

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

Question 33

helicobacter infectious dose

Answer 33

not known for huamns

Question 34

helicobacter diagnosis

Answer 34

radiolabeled urea test
stool culture
seroconversion
PCR
endoscopy

Question 35

helicobacter treatment

Answer 35

bismuth, metronidazole, tetracycline

Question 36

helicobacter vaccine

Answer 36

none