Gram negative Bacillus

Question 1

ANTIGENS of Gram-negative Bacilli

Answer 1

Cell Wall Antigen O

Flagella Antigen H

Capsule Antigen K

Lipid A = Endotoxin

Question 2

Etiologic Agent of Cholera – enterocolitis syndrome (gastroenteritis)

Gram-negative bacillus, curved

Answer 2

Vibrio cholerae

Question 3

Poor sanitation/contaminated water

Answer 3

vibrio cholerae

Question 4

Organisms ingested in large numbers

localize in small intestine

Answer 4

vibrio cholera

Question 5

Enterotoxin exotoxin

stimulates hypersecretion of water/chloride

reverses ion transport

Answer 5

Vibrio cholera

Question 6

“rice water stools”

massive diarrhea/severe dehydration

Answer 6

vibrio cholera

Question 7

etiologic agent of a gastroenteritis due to ingestion of contaminated shellfish (esp. oysters)

Common in coastal waters worldwide

Answer 7

vibrio parahemolyticus

Question 8

Lab diagnosis is by special request.. due to rarity in US

And need special media (alkaline/selectiev)

Answer 8

vibrio cholera

Question 9

Acute gastroenteritis and primary septicemia due to ingestion of raw or undercooked seafood, particularly raw oysters. (very high fatality rate ~50%)

Answer 9

Vibrio vulnificus

Question 10

Severe cellulitis due to seawater contaminating a break in the skin – causes severe skin/tissue infection with hemorrhagic bullae and necrotizing fasciitis. (high fatality rate ~15%)

Answer 10

Vibrio vulnificus

Found in warm, coastal seawater (numbers in US are increasing)

Question 11

Gram-negative bacillus, thin curved rods, occasional “s” or gull wing shapes

Generally originates from ingestion of fecal contaminated food, especially undercooked chicken or contamination of other foods from uncooked chicken, raw milk (from cattle feces), and non-chlorinated water

Answer 11

Campylobacter jejuni

Question 12

Pathogenicity – gastroenteritis (enterocolitis syndrome) – prevalence # 1 or 2 in North America (similar to Salmonella)

Answer 12

Campylobacter jejuni

Question 13

Virulence factors:

(a) Grows in human bile
(b) Flagella promote chemotaxis to colonize the intestine
(c) Adhesive molecules promote attachment
(d) Production of Cytolethal Distending Toxin (CDT) – AB-type toxin that has DNase activity (directly damages DNA)

Answer 13

Campylobacter jejuni

Question 14

(d) Production of Cytolethal Distending Toxin (CDT) – AB-type toxin that has DNase activity (directly damages DNA)

Answer 14

Campylobacter jejuni

Question 15

Microaerophile – Transport & incubate in reduced oxygen (about 5%) & increased CO2

Selective culture media with antibiotics

Answer 15

Campylobacter jejuni

Question 16

GNB (curved)

etiologic agent of peptic ulcers – causes chronic inflammatory lesions of the gastric mucus layer

Answer 16

Helicobacter pylori

Question 17

(1) Breath test to detect urease production

(2) Endoscopy and biopsy – Culture requires microaerophilic environment and special growth media; DNA probe

Answer 17

Helicobacter pylori