Yersinia Selective Agar MCQs Mock Test

Explore the Mock Test of Yersinia Selective Agar MCQs! Learn its uses, preparation, colony morphology, and how it isolates Yersinia enterocolitica and Y. pseudotuberculosis. Covers pH, antibiotics, cold enrichment, ISO standards, and key differentiators from MacConkey Agar. Perfect for microbiology students & lab professionals!

Read the Full Article 50 FAQs and 30 MCQs >>

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Yersinia Selective Agar MCQs Mock Test

Explore Yersinia Selective Agar with 50 FAQs & 30 MCQs! Learn its uses, preparation, colony morphology, and how it isolates Yersinia enterocolitica and Y. pseudotuberculosis. Covers pH, antibiotics, cold enrichment, ISO standards, and key differentiators from MacConkey Agar. Perfect for microbiology students & lab professionals!

Key Features Covered:
✔ Selective & Differential Medium
✔ Mannitol Fermentation (Bulls-eye Colonies)
✔ Cold Enrichment & Incubation Tips
✔ Antibiotics (Cefsulodin, Novobiocin)
✔ Clinical & Food Testing Applications
✔ MCQs for Exam Prep

Ideal for: Medical labs, food safety, and microbiology studies.

Read Full Article: Yersinia Selective Agar 50 FAQs and 30 MCQs

1 / 30

Category: Clinical Laboratory

What is the primary purpose of Yersinia Selective Agar?

Isolate Salmonella

Isolate Yersinia enterocolitica and Y. pseudotuberculosis

Culture Staphylococcus aureus

Detect E. coli O157:H7

2 / 30

Category: Clinical Laboratory

Which ISO standard recommends Yersinia Selective Agar?

ISO 10273 (Yersinia)

ISO 6579 (Salmonella)

ISO 6888 (Staphylococcus)

ISO 16654 (E. coli)

3 / 30

Category: Clinical Laboratory

What confirms Yersinia beyond colony morphology?

Gram staining (Gram-positive rods)

Hemolysis on blood agar

Spore staining

Biochemical tests (e.g., urease, motility)

4 / 30

Category: Clinical Laboratory

Who developed Yersinia Selective Agar?

Schiemann

Louis Pasteur

Joseph Lister

Robert Koch

5 / 30

Category: Clinical Laboratory

If non-Yersinia bacteria grow, what could be the issue?

Overheating

Too much agar

Incorrect pH

Antibiotics not added

6 / 30

Category: Clinical Laboratory

How long can cold enrichment be performed?

Up to 21 days

1 week

2 days

48 hours

7 / 30

Category: Clinical Laboratory

What indicates mannitol fermentation on Yersinia Selective Agar?

Blue-green colonies

Black colonies

Dark pink/red colonies with a bulls-eye appearance

Yellow colonies

8 / 30

Category: Clinical Laboratory

What is the recommended incubation temperature?

42°C

22-32°C

15°C

37°C only

9 / 30

Category: Clinical Laboratory

Which ingredient stimulates Yersinia growth?

Sodium chloride

Crystal violet

Sodium pyruvate

Agar

10 / 30

Category: Clinical Laboratory

How is Yersinia Selective Agar sterilized?

Filtration

Boiling for 5 minutes

Autoclaving at 121°C for 15 minutes

UV radiation

11 / 30

Category: Clinical Laboratory

At what temperature should antibiotics be added?

70°C

45-50°C

d) Room temperature

37°C

12 / 30

Category: Clinical Laboratory

How do Y. enterocolitica colonies appear?

Green metallic sheen

Black with H₂S production

Mucoid and yellow

Dark pink centers with translucent borders (bulls-eye)

13 / 30

Category: Clinical Laboratory

Which organism grows with dark pink centers but no translucent zone?

Proteus mirabilis

Y. pestis

E. coli

Y. pseudotuberculosis ✔

14 / 30

Category: Clinical Laboratory

What is a limitation of this medium?

Requires anaerobic incubation

Turns blue on contamination

Inhibits all Gram-negatives

Cannot detect Y. pestis

15 / 30

Category: Clinical Laboratory

What type of medium is Yersinia Selective Agar?

Transport medium

Selective and differential

Chromogenic

Enriched only

16 / 30

Category: Clinical Laboratory

What is the role of neutral red in the agar?

pH indicator (red at pH <6.8)

Nutrient source

Antibiotic

Bile salt

17 / 30

Category: Clinical Laboratory

Mannitol-negative organisms produce:

Blue colonies

Red colonies

Swarming growth

Colorless, translucent colonies

18 / 30

Category: Clinical Laboratory

Which virulence factor helps Yersinia evade immunity?

Coagulase

Enterotoxin

Yops (Yersinia outer proteins)

Capsule

19 / 30

Category: Clinical Laboratory

Which sugar is used as a fermentable substrate in this medium?

Glucose

Lactose

Sucrose

Mannitol

20 / 30

Category: Clinical Laboratory

Which of the following samples can be tested using Yersinia Selective Agar?

Blood only

Urine only

Sputum only

Stool, food, and water

21 / 30

Category: Clinical Laboratory

Cold enrichment works because Yersinia is:

Thermophilic

Halophilic

Acidophilic

Psychrotrophic

22 / 30

Category: Clinical Laboratory

Which bacteria may resemble Yersinia on this agar?

Streptococcus pyogenes

Aeromonas and Citrobacter

Clostridium difficile

Neisseria gonorrhoeae

23 / 30

Category: Clinical Laboratory

Why is cold enrichment (4°C) used?

To kill other bacteria

To solidify the agar

To reduce contamination

To enhance Yersinia recovery

24 / 30

Category: Clinical Laboratory

Which animal is a major reservoir for Y. enterocolitica?

Chickens

Fish

Pigs

Cows

25 / 30

Category: Clinical Laboratory

What is the pH of Yersinia Selective Agar?

7.4 ± 0.2

6.2 ± 0.2

8.0 ± 0.2

5.5 ± 0.2

26 / 30

Category: Clinical Laboratory

Which component inhibits Gram-positive bacteria?

Sodium chloride

Magnesium sulfate

Neutral red

Sodium deoxycholate and crystal violet

27 / 30

Category: Clinical Laboratory

Which disease is NOT caused by Yersinia enterocolitica?

Lymphadenopathy

Pneumonia

Gastroenteritis

Bubonic plague (Y. pestis causes plague)

28 / 30

Category: Clinical Laboratory

Why are cefsulodin and novobiocin added?

To enhance pigment production

To neutralize toxins

To increase selectivity for Yersinia

To solidify the medium

29 / 30

Category: Clinical Laboratory

What is a key biochemical test for Y. enterocolitica?

Urease-positive

Oxidase-positive

Citrate-positive

Indole-positive

30 / 30

Category: Clinical Laboratory

How should prepared plates be stored?

-20°C

Room temperature

2-8°C

37°C

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Read the Full Article 50 FAQs and 30 MCQs >>

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