Vibrio, Campylobacter, Helio

Question 1

Gram negative, curved rod, facultative anaerobe, single flagellum

Answer 1

Vibrio cholera

Question 2

What is a serogroup?

Answer 2

Bacteria of the same species with different antigenic determinants on the cell surface

Question 3

What is a biotype?

(biovar)

Answer 3

Different strains of the same bacterial species

distinguished by a group of phenotypic or genetic traits

Question 4

How many serogroups of V.cholera cause epidemic disease?

Answer 4

2

Question 5

How many chromosomes does V.cholera have?

Answer 5

2 circular chromosomes

Question 6

Which chromosome of V.cholera contains pathogenicity islands?

Answer 6

Answer: Chromosome II

Chromosome I - larger and contains genes for cell function and housekeeping.

Chromosome II is smaller and carries integron island (genes with antibiotic resistance)

Question 7

What is Cholera Toxin?

Answer 7

CT is a proteinaceous enterotoxin secreted by
V. Cholera
-responsible for the severe diarrhea characteristic of the disease.

Question 8

Describe the pathogenicity of Cholera Toxin

Answer 8

Short Answer: Absorption of cholera toxin causes diarrhea via increase in cyclic AMP

Long Answer: absorption of CT–>adenylate cyclase–>formation of cAMP–>secretion of chloride and bicarbonate–>secretion of large amount of water in lumen

Question 9

How is cholera diagnosed?

Answer 9

Rice water stool

Question 10

How is cholera treated?

Answer 10

Replace fluids/electrolytes

Question 11

The following are characteristics common to the superfamily for which two species?

• Gram negative
• Helical (spiral or curved)
• Pleomorphic
• Microaerophilic (curve when exposed to air)
• Neither ferment nor oxidize carbohydrates

Answer 11

campylobacter and heliobacter

Question 12

Most common cause of acute infectious diarrhea in developed countries

Answer 12

campylobacter (jejuni)

Question 13

Gull-winged appearance

Answer 13

campylobacter

Question 14

• small, thin, helical (spiral or curved)
• gram negative
• tendency to become coccoid and elongated *upon exposure to air or prolonged culture
• gull-winged

Answer 14

campylobacter

Question 15

What is a capnophile?

Answer 15

An organism that prefers an CO2 environment

Question 16

• Distinctive rapid “darting motility”
• Long sheathed polar flagellum
• microaerophilic & capnophilic
• thermophile
• often nonculturable

Answer 16

campylobacter

Question 17

A secondary autoimmune disease resulting from campylobacter jejuni infection. Causes acute inflammatory demyelinating neuropathy in response to cross-reaction to O-antigens.

Answer 17

Answer: Guillain-Barre Syndrome

associated with C. jejuni serogroup O19

Question 18

How do humans acquire Campylobacteriosis?

Answer 18

• Ingestion of contaminated food (particularly poultry), unpasteurized milk, or improperly treated water
• Foods that neutralize gastric acidity, e.g., milk. *Fecal-oral transmission

Question 19

Which Campylobacter has an S-layer protein “microcapsule” ?

Answer 19

Answer: C. fetus

Causes zoonotic abortion

Question 20

Cellular virulence factors for Campylobacter?

Answer 20

Endotoxin
Flagellum: Motility
Adhesins: Mediate attachment to mucosa
Invasins
GBS is associated with C. jejuni serogroup O19
S-layer protein “microcapsule” in C. fetus:

Question 21

Extracellular virulence factors for Campylobacter?

Answer 21

Enterotoxins

Cytopathic toxins

Question 22

Describe gastroenteritic pathogenesis of Campylobacter jejuni

Answer 22

Damage to the mucosal surfaces of the jejunum, ileum, colon

Inflammatory process due to invasion into the intestinal tissue

Question 23

Describe Lab Identification of Campylobacter jejuni using microscopy

Answer 23

Gull-wing appearance in gram stain

Darting motility in fresh stool

Question 24

Name 3 important pathogens of the Helicobacter species

Answer 24

Helicobacter pylori (human; no animal reservoir)

H. cinaedi (male homosexuals; rodents)

H. fenneliae (male homosexuals; rodents)

Question 25

Major human pathogen associated with chronic gastritis?

gastric ulcers

Answer 25

Answer: Helicobacter pylori

Colonize mucosal lining of stomach & duodenum. Preceded/Concurrent with gastric adenocarcinomas and lymphomas

Question 26

Virulence factors for Helicobacter (5 factors)

Answer 26

1.Multiple polar, sheathed flagella
2.Adhesins: Hemagglutinins
3.Mucinase: Degrades gastric mucus; Localized tissue damage
4.Urease: converts urea into bicarbonate (to CO2) and ammonia
Neutralize the local acid environment
Localized tissue damage
5.Acid-inhibitory protein

Question 27

How is Helicobacter treated?

Answer 27

Requires long treatment with multiple antibiotics along with proton pump inhibitor. Breath test to detect urease. inadequate treatment results in recurrence of symptoms