Yersinia

Question 1

What are the pathogenic species of Yersinia?

Answer 1

1. Yersinia enterocolitica
2. Yersinia pseudotuberculosis
3. Yersinia pestis

Yersinia enterocolitica causes foodborne enterocolitis, Yersinia pestis is responsible for bubonic and pneumonic plague.

Question 2

What clinical features are associated with Yersinia enterocolitica?

Answer 2

Diarrhoea, fever, abdominal pain, necrosis of Peyer’s patches, mesenteric lymphadenitis, bloodstream infections, bloody diarrhoea in children

Mesenteric lymphadenitis can mimic appendicitis, especially in children.

Question 3

What are the reservoirs for Yersinia enterocolitica?

Answer 3

Animals, pets, soil, lakes

This indicates potential sources of infection.

Question 4

How is Yersinia enterocolitica transmitted?

Answer 4

Via food: milk, pork, poultry, shellfish, vegetables

This highlights the importance of food safety.

Question 5

What is the incubation period for Yersinia enterocolitica infection?

Answer 5

24–36 hours

This indicates the time from exposure to onset of symptoms.

Question 6

What type of bacteria is Yersinia enterocolitica?

Answer 6

Gram-negative bacilli (GNB)

This classification helps in identifying the organism in lab settings.

Question 7

What biochemical characteristics are observed in Yersinia enterocolitica at 30°C?

Answer 7

• Oxidase –
• Weak Catalase +
• I: +
• M: –
• V: +
• iC: –
• Urease: +
• Lysine Decarb: –
• Ornithine Decarb: +
• Motile at 25°C, Non-motile at 37°C
• NLF on MacConkey

These characteristics aid in laboratory identification.

Question 8

What disease is caused by Yersinia pestis?

Answer 8

Plague

Plague can manifest as bubonic or pneumonic forms.

Question 9

What are the symptoms of bubonic plague?

Answer 9

Painful swollen lymph nodes (buboes)

This is a hallmark symptom of bubonic plague.

Question 10

How is pneumonic plague transmitted?

Answer 10

Person-to-person spread

This mode of transmission highlights the infectious risk in close contact situations.

Question 11

What are the primary transmission methods for Yersinia pestis?

Answer 11

• Flea bites
• Direct contact with infected animals

Understanding these transmission routes is crucial for prevention.

Question 12

Fill in the blank: Yersinia enterocolitica is a _______ that can grow at 4°C.

Answer 12

psychrotroph

This characteristic indicates it can pose a cold chain hazard.

Question 13

What laboratory tests are used for Yersinia enterocolitica identification?

Answer 13

• Direct PCR: BioFire GI Panel, BD Max
• Culture: CIN Agar
• Biochemical ID: API 20E, VITEK GN, MALDI

These tests are essential for accurate diagnosis.