Lecture 4 Part 3: Vibrio, Campylobacter, & Helicobacter

Question 1

What does Vibrio cholerae cause?

Answer 1

Vibrio cholerae is responsible for cholera outbreaks

Question 2

Is Vibrio cholerae commensal?

Answer 2

Vibrio cholerae is NEVER commensal

Question 3

What is required for V. cholerae to cause significant disease?

Answer 3

A large number of organisms must be ingested

Question 4

Where is V. cholerae primarily found and what does it require for growth

Answer 4

V. cholerae is primarily found in water and requires NaCl (salt) for growth

Question 5

Describe the shape and Gram stain of Vibrio bacteria

Answer 5

Vibrio bacteria are Gram-negative curved rods with polar flagella

Question 6

Are Vibrio bacteria oxidase-positive or oxidase-negative?

Answer 6

A: Vibrio bacteria are oxidase-negative

Question 7

What type of metabolism do Vibrio bacteria have?

Answer 7

Vibrio bacteria are facultative anaerobes

Question 8

Name three medically relevant species of Vibrio?

Answer 8

1. Vibrio cholerae
2. Vibrio parahaemolyticus
3. Vibrio vulnificus

Question 9

What is the exotoxin associated with Vibrio cholerae?

Answer 9

The exotoxin is cholera toxin, which is carried on a bacteriophage (CTXΦ) that binds to Vibrio cholerae sex pili (toxin co-regulated pili – TCP)

Question 10

How is cholera toxin genetic material integrated into the Vibrio cholerae genome?

Answer 10

The genetic material for cholera toxin is integrated into the Vibrio cholerae genome

Question 11

What are the other pathogenicity genes associated with Vibrio cholerae? (hint; there is 3 of them)

Answer 11

ace genes – accessory cholera enterotoxin
zot genes – zonula occludens toxin
cep gene – chemotaxis proteins

Question 12

Name the three virulence factors for vibro

Answer 12

1. endotoxin
2. cholera toxin
   3, other pathogenicity genes

Question 13

What type of toxin is cholera toxin?

Answer 13

exotoxin

Question 14

What effect does cholera toxin have on cAMP levels in host cells

Answer 14

Cholera toxin causes an overproduction of cAMP

Question 15

What is the mechanism of action of cholera toxin?

Answer 15

Cholera toxin is an exotoxin that overproduces cAMP and modifys the host’s adenylate cyclase

Question 16

Which Vibrio cholerae strain has caused seven major pandemics?

Answer 16

The VO1 El Tor serotype is responsible for seven major pandemics
is endemic in Africa and Latin America

Question 17

What new ability did the VO139 Bengal strain acquire?

Answer 17

The ability to produce a capsule

Question 18

How was the mutation in the VO139 Bengal strain traced?

Answer 18

It was traced to the insertion of a new sequence into the O1 gene created new virulent strain.

Question 19

Does previous exposure to VO1 strains provide immunity against the VO139 Bengal strain?

Answer 19

No, previous exposure to VO1 strains does not provide immunity against the VO139 Bengal strain

Question 20

What are the four Campylobacter species associated with human disease?

Answer 20

1. C. jejuni
2. C. coli
3. C. fetus
4. C. upsaliensis

Question 21

What is the shape and Gram reaction of Campylobacter?

Answer 21

Thin, curved, Gram-negative rods

Question 22

What feature gives Campylobacter its motility?

Answer 22

Polar flagellum

Question 23

What type of oxygen conditions does Campylobacter require?

Answer 23

Microaerobic (requires low oxygen conditions)

Question 24

What are the primary diseases caused by Campylobacter?

Answer 24

Gastroenteritis and septicemia (mainly C. fetus)

Question 25

True or False Campylobacter infections are LESS common than Salmonella and Shigella.

Answer 25

False – Campylobacter infections are MORE common

Question 26

What is the primary mode of transmission for Campylobacter?

Answer 26

Zoonotic – transmitted from animal reservoirs

Question 27

What is the exotoxin produced by Campylobacter?

Answer 27

Cytolethal-distending toxin (CDT)

Question 28

What bacterial components contribute to Campylobacter virulence?

Answer 28

LOS (lipooligosaccharide) and LPS (lipopolysaccharide)

Question 29

What part of the gastrointestinal tract does C. jejuni affect?

Answer 29

Ulcerates the mucosal surface of the jejunum, ileum, and colon

Question 30

What virulence factor does C. fetus have, and what is its function?

Answer 30

S protein – heat stable, blocks C3b binding, increases risk for systemic infections

Question 31

Name 2 primary gastrointestinal infections caused by Campylobacter?

Answer 31

1. Acute enteritis 2. colitis

Question 32

What autoimmune disorder is associated with C. jejuni and C. upsaliensis?

Answer 32

Guillain-Barré syndrome – an autoimmune disorder of the PNS leading to progressive, transient muscle weakness

Question 33

How does Campylobacter contribute to Guillain-Barré syndrome?

Answer 33

antibodies against pathogen attack peripheral nerve tissue

Question 34

What are the extraintestinal complications of Campylobacter infections?

Answer 34

Reactive arthritis and meningoencephalitis

Question 35

What are the two major groups of Helicobacter?

Answer 35

Gastric and Enterohepatic

Question 36

Which Helicobacter species is associated with gastric diseases?

Answer 36

H. pylori

Question 37

Which Helicobacter species belong to the enterohepatic group?

Answer 37

H. cinaedi and H. fennelliae

Question 38

What is the shape and Gram classification of Helicobacter pylori?

Answer 38

Curved or spiral, Gram-negative rods (mature coccoid form)

Question 39

What enzyme is produced in high levels by gastric forms of Helicobacter pylori?

Answer 39

Urease is produced in high levels by gastric forms of Helicobacter pylori

Question 40

What type of motility does Helicobacter pylori exhibit?

Answer 40

Helicobacter pylori are highly motile with polar flagella

Question 41

What are the oxidase and catalase characteristics of Helicobacter pylori?

Answer 41

Helicobacter pylori are Oxidase(+) and Catalase(+)

Question 42

Does Helicobacter pylori ferment or oxidize carbohydrates?

Answer 42

Helicobacter pylori do not ferment or oxidize carbohydrates

Question 43

Where does Helicobacter pylori often establish chronic colonization?

Answer 43

Helicobacter pylori often establish chronic colonization of the stomach

Question 44

What is the primary reservoir for H. pylori?

Answer 44

humans

Question 45

What role does the bacterial acid-inhibitory protein play in Helicobacter pylori colonization? clarifyyyy

Answer 45

The bacterial acid-inhibitory protein helps Helicobacter pylori survive in the acidic environment of the stomach by inhibiting acid production.

Question 46

What virulence factor helps H. pylori neutralize stomach acid?

Answer 46

Urease activity, which converts urea into ammonia to neutralize acid

Question 47

What is the role of adhesins in Helicobacter pylori infection?

Answer 47

Adhesins bind to the gastric epithelium more info: so it can colonize and persist in stomach

Question 48

What toxin does H. pylori produce and what does it do?

Answer 48

Vacuolating cytotoxin A (VacA)a toxin that primarily causes the formation of vacuoles within host cells, leading to cell damage and apoptosis

Question 49

What is the function of cagA in H. pylori virulence?

Answer 49

It is a cytotoxin-associated gene delivered by the Type IV secretion system more info: acts as a key virulence factor by being injected into host gastric epithelial cells, where it disrupts normal cell signaling pathways, leading to chronic inflammation and significantly increasing the risk of gastric cancer

Question 50

What diseases can Helicobacter pylori cause in the stomach? in other words Name the 4 dieases associated with Gastric helicobacter (H. pylori)

Answer 50

1. Gastritis (acute and chronic) 2. development of ulcers 3. chronic infection- tissue replaced with fibrotic growth (risk for cancer) 4. MALT lymphoma (stomach cancer)

Question 51

What is the risk associated with chronic H. pylori infection?

Answer 51

Chronic H. pylori infection can lead to tissue damage, fibrosis, and an increased risk of cancer

Question 52

Which Helicobacter species are associated with gastroenteritis and bacteremia?

Answer 52

Helicobacter cinaedi and Helicobacter fennelliae are associated with gastroenteritis and bacteremia

Question 53

What type of cancer is associated with H. pylori infection?

Answer 53

MALT lymphoma mucosa-associated lymphoid tissue (MALT)