Vibrio (pathogens related to enteric tract)

Question 1

Important properties:
Meaning what is the classification of this bacteria ?

Shape:
Gram stain :
Oxidase :
Fermentation:

Answer 1

Curved comma shaped

Gram negative ROD

Oxidase positive

Ferments Glucose

memorize this in algorithm of gram negative

Question 2

Pathogenesis

Answer 2

• Dependent on colonization of small intestine
• Enterotoxin
• Can cause cellulitis and sepsis
• Vibrio cholerae, parahaemolyticus and vulnicus

Question 3

Transmission

Answer 3

Fecal contamination

Carriers are asymptomatic

Bacteria must be ingested

Question 4

Epidemiology:

Answer 4

Vibrio was the major epidemic of cholera in 1970

Mortality rate w/ out Tx is 40%

Question 5

Mechanism pathway of infection:

Vibrio

Answer 5

1. Ingestion of bacteria
2. Adherence to brush borders of the gut
3. Multiplication of the bacteria
4. Secretion of ENTEROTOXIN (Cholera Toxin)

Question 6

Toxin:

Vibrio

Answer 6

Cholera toxin: produces the symptoms of even in the absence of Vibrio

Choleragen: consist of: Active and Binding subunits;

Question 7

How is diarrhea caused in vibrio

Vibrio

Answer 7

Over stimulation of adenylate cyclase
2. Increased cAMP
3. Activation of AMP-dependent protein kinase
4. Severe phosphorylation

Dehydration: loss of water and ions
Rice-water stools (non bloody)

Question 8

Acidosis and hypokalemia (loss of bicarbonate and potassium in the stool

Vibrio

Answer 8

because of overactive adenylate cyclase it causes instructions in second messenger systems to have an over active GI and causes diarrhea.

increased cAMP: disturb ion channel signals to open and close, therefore cause hyperactive motility and kicks fluid out of the body resulting in dehydration

water and and electrrolyre loss = dehydration
understand this concept !

Question 9

ABX treatment

Vibrio

Answer 9

Tetracyclines

but not necessary
does not shorten the duration of the disease

Question 10

Vaccine: (not available in US and no longer in use) page 160 Immunology and Microbiology book

Vibrio

Answer 10

1st vaccine:
Oral vaccine: two oral vaccines
Dukoral: killed whole cells of O-1 strains + recombinant cholera toxin subunit B
2nd vaccine:
Killed cell vaccine (shanchol)
Contains both O-1 and O-159 strains

Question 11

V. parahaemolyticus

Answer 11

Shellfish, oysters, seafood
Enterotoxin same as choleragen
Mild to severe diarrhea
Growth: NaCl

Question 12

V. Vulnificus

Answer 12

Raw seafood
uncooked seafood
liver disease: cirrhosis
Tx ABX: Doxycycline
Cellulitis
Skin: Hemorrhagic bullae on