Vibrio Multiple Choice Question And Answers

1. A lady who was admitted in the hospital for diarrhea after attending Kumbh Me The organism picture is given. What type of motility the organism exhibits?

Read And Learn More: Micro Biology And Immunology Multiple Choice Question And Answers

1. Tumbling motility
2. Darting motility
3. Stately motility
4. Corkscrew motility

Answer. (2) (Darting motility)

Vibrio Vulnificus

Vibrio Cholerae

2. In the small intestine, cholera toxin acts by:

1. ADP ribosylation of the G regulatory protein
2. Inhibition of adenyl cyclase
3. Activation of GTPase
4. Active absorption of NaCl

Answer. (1) (ADP ribosylation of the G protein)

• Cholera toxin causes ADP ribosylation of G protein → upregulates the activity of adenylate cyclase → results in the intracellular accumulation of CAMP.

3. Cholera patient having stool output 1000-1500 ml/day is known as:

1. Cholera mitis
2. Cholera dumdum
3. Cholera magna
4. Cholera gravis
5. Cholera intermedius

Answer. (4) (Cholera gravis)

Sudden onset of explosive life-threatening diarrhea is known as cholera gravis, seen in 5% of cases.

4. Vibrio cholerae differs from E.coli by:

1. Oxidase test
2. Catalase test
3. Optochin sensitive
4. Lactose fermenter

Answer. (1) (Oxidase test)

• Vibrio cholerae is oxidase positive; E.coli is oxidase negative
• Vibrio cholerae can ferment lactose late, hence called as late lactose fermenter.

5. Vibrio cholerae toxin acts by disrupting which of the following structures?

1. Hemidesmosome
2. Gap junctions
3. Zona occludens
4. Zona adherens

Answer.(3) (Zona occludens)

Vibrio Cholerae

Vibrio Vulnificus

Vibrio cholerae elaborates Zona occludens toxin (Zot), a protein that increases the permeability of small intestinal mucosa by disrupting the intercellular tight junctions between mucosal cells.

6. Channel activated by cholera toxin:

1. Adenylate cyclase
2. Guanyl cyclase
3. ABC transport channel
4. Iron transport channel

Answer. (1) (Adenylate cyclase)

• Cholera toxin causes ADP ribosylation of G protein → upregulates the activity of adenylate cyclase → result is ↑ cAMP.

7. Which of the following statement(s) is/are wrong about the 8th pandemic of cholera?

1. Caused by Vibrio cholerae O139
2. Started in 1992
3. Started in Bangladesh
4. Mostly confined to Bangladesh & India
5. Capsulated

7. Answer.(3) (Started in Bangladesh)

O139 (The Bengal strain) was isolated first from Chennai in 1992 and spread rapidly along the costal region of way of Bengal up to West Bengal, then to the adjacent areas of Bangladesh .

8. Cholera toxin attaches to which receptor?

1. GD1
2. GM1
3. GM2
4. GD2

Answer. (2) (GM1)

9. True about mechanism of bacterial toxins:

1. Cholera toxin acts by inhibition of guanylcyclase
2. Botulinum toxin inhibits Ach release
3. Shiga toxin of Shigelladysenteriae act by inhibiting protein synthesis
4. Diphtheria toxin act by inhibiting protein synthesis

Answer. (2, 3, 4) (Botulinum toxin inhibits Ach release, Shiga toxin toxin of Shigelladysenteriae act by inhibiting protein synthesis, Diphtheria toxin act by inhibiting protein synthesis)

Vibrio Cholerae

• Cholera toxin acts by activating cAMP
• Botulinum toxin inhibits Acetylcholine release at NM junction → flaccid paralysis
• Shiga toxin of Shigella dysenteriae acts by inhibiting protein synthesis by inhibiting ribosome
• Diphtheria toxin act by inhibiting protein synthesis by inhibiting elongation factor-2

Vibrio Vulnificus

10. Invasive infections caused by all except:

1. Shigella
2. Salmonella
3. V. cholerae
4. Yersinia

Answer.(3) (V. cholerae)

• V. cholerae is noninvasive The pathogenesis of V. cholerae is due to exotoxin.

11. The endotoxin of the following gram-negative bacteria does not play any part in the pathogenesis of the natural disease:

1. E.coli
2. Klebsiella
3. Vibrio cholerae
4. Pseudomonas

Answer. (3) (Vibrio cholerae)

• Cholera Vibrios also possess lipopolysaccharide O antigen (LPS, endotoxin) as in other gram-negative intestinal bacilli. But unlike other gram-negative bacilli like E.coli, Klebsiella, and Pseudomonas, et(where endotoxin is the principle virulence factor), LPS apparently plays no role in pathogenesis of cholera but is responsible for the immunity induced by killed vaccine.
• For Vibrio cholerae the principle virulence factor is the exotoxin, i.cholera toxin.

12. Tetracycline is used in prophylaxis of:

1. Shigellosis
2. Cholera
3. Brucellosis
4. Leptospirosis

Answer. (2) (Cholera)

DOC for chemoprophylaxis for cholera- Tetracycline

13. Cholera is caused by:

1. Vibrio cholerae 01
2. Vibrio cholerae 0139
3. Vibrio parahemolyticus
4. NAG Vibrio

Answer. (1, 2, 4) (Vibrio cholerae 01,Vibrio cholerae 0139, NAG Vibrio)

• Epidemic and pandemic Cholera is caused by both Vibrio cholerae O1 and O139 strains.
• However, Cholera like illness can also be caused by NAG (Nonagglutinable Vibrio), i.e.V cholerae serogroups non-O1/non-O139.

14. True about Vibrio cholerae is:

1. Disease more common in woman
2. Classical Vibrio protect against development of O-139
3. ElTor is milder than classical
4. Erythromycin is used in treatment

Vibrio Cholerae

Answer. (3) (ElTor is milder than classical)

• ‘ElTor is much hardier and resistant than classical, But ElTor produces less severe cholera
• Hence, ElTor infection leads to more carrier than cases

About Other Options:

• Classical Vibrio belongs to serovar O1, which is antigenically different from Serovar O139, it cannot protect against it.
• But Classical Vibrio protect against development of ElTor.
• Cholera Vibrio affects all ages and sexes but in epidemic area it affects more children.

15. Darting motility which occur in V.cholerae, also found in:

1. Shigella
2. Campylobacter jejuni
3. Pneumococcus
4. Bacillus anthrax
5. Aeromonas

Answer. (2) (Campylobacter…)

• Campylobacter jejuni possess single polar flagella and, they exhibit darting motility appreciated under dark field or phase contrast microscopy.

Vibrio Vulnificus

16. Selective media for Vibrio:

1. TCBS
2. Stuart
3. Skirrow’s
4. MYPA

Answer. (1) (TCBS)

• TCBS (Thiosulfate Citrate Bile salts Sucrose Agar) is a Selective media for Vibrio.
• V. Cholerae can ferment sucrose and it produces Yellow colonies on TCBS.
• Whereas V.parahemolyticus produces green colonies on TCBS Culture medias for Vibrio.

17. Which of the following bacteria act by increasing c-AMP:

1. Vibrio cholerae
2. Staphylococcus aureus
3. E.coli, heat stable toxin
4. Salmonella

Answer. (1) (Vibrio cholerae)

Vibrio Cholerae

• Mechanism of action of cholera toxin refer text (chapter review).
• Toxin acts by cAMP are: LT of E.coli, Cholera toxin, Pertussis toxin, Anthrax toxin (edema factor).

18. True about V. cholera 0139 all except:

1. Clinical manifestations are similar 01 ElTor strain
2. First discovered in Chennai
3. Epidemiologically indistinguishable from 01 ElTor strain
4. Produces 01 Lipopolysaccharide

Answer. (4) (Produces 01 …)

• V. Cholerae O139 possesses LPS serogroup O139, not O1.

19. True about Cholera is:

1. Can be transmitted by food
2. Vaccination gives 90% efficiency
3. Healthy carrier
4. Chlorination is not effective

Answer. (1, 3) (Can be transmitted by food, Healthy carrier)

• Cholera is transmitted by contaminated water & food, direct contact through finger from carriers

About Other Options:

• Option b: Vaccination gives protection rate of 50–60% ……………….
• Option d: Chlorination is effective rural area, water can be made safe from cholera
  bacilli by boiling or chlorination’ Park 22/e p209.

20. V. cholerae is able to stay in GIT because of:

1. Acid resistance
2. Bile resistance
3. Motility
4. Binds to specific
5. Anaerobic potential receptors

Vibrio Vulnificus

Answer. (2, 3, 4) (Bile resistance, Motility, Binds to specific)

• V. cholerae is acid labile that is why high infective dose of 106 bacilli is required to cross the gastric juice barrier. (and achlorohydria facilitates transmission)
• V. cholerae is bile resistant, hence can survive in the intestin(bile resistant property helps to grow on TCBS
• V. cholerae is strongly aerobic but still grows slowly and scanty anaerobically.

Other reasons include:

• Factors that help to cross the protective mucus layer in small intestine are motility,chemotaxis, mucinase, and other proteolytic enzymes.
• Other factors: Siderophore, neuraminidase, accessory colonizing factor Adhere to epithelium by TCP (Toxin Co-regulatory Pilus)
• Cholera Toxin: Principle virulence factor binds to specific GM1 receptor on intestinal epithelium.

Vibrio Cholerae

21. Cholera toxin:

1. Increases the levels of intracellular cGMP
2. Acts through the receptor the opiates
3. Causes continued activation of Adenylate cyclase
4. Inhibits the enzyme phosphodiesterase

Answer. (3) (Causes continued activation of Adenylate cyclase)

Cholera Toxin (CT): causes ADP ribosylation of G protein → Adenyl cyclase → cAMP

22. Which of the following is the drug of choice of chemoprophylaxis of cholera?

1. Tetracycline
2. Doxycycline
3. Furazolidone
4. Cotrimoxazole

Answer. (1) (Tetracycline)

• DOC for chemoprophylaxis- Tetracycline

23. For cholera control: all recommended except:

1. Mass chemoprophylaxis
2. Early case detection
3. Chlorination of water
4. Proper disposal of excreta

Answer. (1) (Mass chemoprophylaxis)

• Mass chemoprophylaxis is not recommended for the control of cholera
• Measures for cholera control includes:
  • Early case detection
  • Water control by Chlorination of water
  • Proper disposal of excreta.

24. A stool examination was carried out which showed organism with darting motility.Which of the following organism may be present in stool?

1. V. cholerae
2. Shigella
3. Salmonella
4. Campylobacter jejuni
5. coli

Answer. (1, 4) (V. cholerae, Campylobacter jejuni)

Darting or shooting star motility is exhibited by V. cholerae and Camplyobacter jejuni.

25. Type of diarrhea in Vibrio cholerae:

1. Osmotic
2. Secretory
3. Colloidal
4. Bloody

Answer. (2) (Secretory)

• Cholera stool is painless voluminous watery secretory diarrhea with non bilious, gray, slightly cloudy fluid with flecks of mucus, no blood, and sweet, inoffensive, non invasive diarrhea (So no pus cells in stool).

26. The best way to classify organism associated with epidemics of watery diarrhea in Southeast Asia:

1. Phage typing
2. Biotyping
3. Colicin typing
4. Antibiogram typing

Answer. (2) (Biotyping)

• Organism associated with epidemics of watery diarrhea in Southeast Asia- suggestive of V. cholerae.
• V. cholerae is commonly typed by serotype (O1 to O139) and O1 is further biotypes to classical and Eltor.

27. Halophilic vibrios include?

1. Vibrio cholerae
2. Vibrio parahaemolyticus
3. Vibrio vulnificus
4. Vibrio alginolyticus
5. Vibrio mimicus

Answer. (2, 3, 4)

• V. cholerae and V.mimicus are not halophilic.

28. Patient present with watery diarrhea after 24 hours of sea food ingestion. Probable organism is:

1. Vibrio parahemolyticus
2. Salmonella typhimurium
3. Shigella flexneri
4. Campylobacter

Answer. (1) (V. parahemolyticus)

Vibrio Cholerae

V. parahemolyticus causes Food-borne gastroenteritis following raw or uncooked seafood (e.g. oyster) intakIt commonly presents as watery diarrhea or rarely as dysentery with abdominal cramps.

29. A Gram-negative marine bacterium that causes ear infection:

1. Vibrio cholerae
2. Vibrio parahemolyticus
3. Vibrio alginolyticus
4. Vibrio mimicus

Answer.(3) (Vibrio alginolyticus)

• V. alginolyticus occasionally causes eye, ear, and wound infections.
• V. alginolyticus is associated with infection of ear, eye and wounds in human beings exposed to sea water.

30. Vibrio parahemolyticus is seen in undercooked:

1. Crab
2. Shellfish
3. Prawn
4. Fish

Answer. (2) (Shellfish)

Vibrio Vulnificus

31. All of the following Vibrio sp. are halophilic, except:

1. V. cholerae
2. V. parahaemolyticus
3. V. alginolyticus
4. V. fluvialis

Answer. (1) (V. cholerae)

Examples of Halophilic Vibrio –V. alginolyticus, V. parahemolyticus, V. vulnificus & V.fluvialis

Examples of Non-Halophilic Vibrio V. cholerae and V. mimicus

32. A 32-year-old male, Kallu, who recently visited a sea coast presented with ulcer over left leg. The probable cause is:

1. Pasteurella multocida
2. Micrococcus halophillus
3. Vibrio vulnificus
4. Neisseria gonorrheae

Answer.(3) (V. vulnificus)

Vibrio Oysters

Points in Favor: Person belongs to Sea coast presented with ulcer over the left leg ‘Halophilic Vibrio usually cause infection in sea coastal region following ingestion of seafood like Oysters, etc.‘

33. Vibrio parahemolyticus true is:

1. Cannot tolerate maximum 1% salt
2. Cannot tolerate maximum 3% salt
3. Cannot tolerate maximum 7% salt
4. Cannot tolerate maximum 10% salt

Answer. (4) (Cannot tolerate maximum 10% salt)

V. parahemolyticus can tolerate up to 8% of salt concentration,