How do you identify Yersinia pestis?

How do you identify Yersinia pestis?

Yersinia pestis is a nonmotile, slow-growing, facultative organism classified in the family Enterobacteriaceae. It appears as plump, gram-negative coccobacilli that are seen mostly as single cells or pairs, which may exhibit bipolar staining from a direct specimen if stained with Wright’s or Giemsa stains.

What does Yersinia look like?

Yersinia pestis — Colony Characteristics Growth at 24 hours is tiny, almost invisible, shiny gray, translucent “spots.” At 48 to 72 hours, colonies are 1 to 2 mm irregular, gray-white to slightly yellow in color, and have a raised, irregular, “fried egg” appearance, which become prominent as the culture ages.

What is the shape of the bubonic plague?

The disease is caused by a coccobacillus-shaped, gram negative bacterium referred to as Yersinia pestis.

What is the size of Yersinia pestis?

Gram negative rod-ovoid 0.5-0.8 µm in width and 1-3 µm in length (safety pin appearance), bipolar staining (Giemsa) facultative intracellular, non-motile.

What are the virulence factors of Yersinia pestis?

pestis expresses several virulence factors, including F1 antigen, Psa, and four Yops (YopT, YopH, YopE, and YpkA) which are employed to resist phagocytosis by the surrounding professional phagocytes.

What are the characteristics of Yersinia?

Yersinia pestis — Key Characteristics

• Gram-negative bacilli, possible bipolar staining and a “safety pin” appearance.
• Nonhemolytic.
• Growth is faster at 25 to 28 degrees C than at 35 to 37 degrees C.
• At 48 to 72 hours the colonies on sheep blood agar have a “fried egg” appearance.
• Catalase positive.

What are the characteristics of Yersinia pestis?

Gram-negative bacilli, possible bipolar staining and a “safety pin” appearance. Growth is faster at 25 to 28 degrees C than at 35 to 37 degrees C. At 48 to 72 hours the colonies on sheep blood agar have a “fried egg” appearance.

Is Yersinia pestis photosynthetic chemosynthetic or heterotrophic?

Yersinia pestis is heterotrophic. This means that it obtains its organic molecules in organic form from other organisms.

How does Yersinia pestis cause the plague?

Bubonic plague is the most common form of plague and is caused by the bite of an infected flea. Plague bacillus, Y. pestis, enters at the bite and travels through the lymphatic system to the nearest lymph node where it replicates itself. The lymph node then becomes inflamed, tense and painful, and is called a ‘bubo’.

Is Yersinia pestis autotrophic or heterotrophic?