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 is the morphology of Yersinia pestis?
Major characteristics of Yersinia pestis: Gram stain morphology: Gram negative rods, 0.5 x 1-2 µm Colony morphology: Slow growing, pinpoint colonies after 24h; colonies are 1-2 mm, gray-white to slightly yellow and opaque on BAP after 48 h; non-lactose fermenter on MAC/EMB; growing both at 25-28°C and at 35-37°C.
How does Yersinia pestis grow?
pestis grows as part of biofilm in the flea, flea-transmitted bacteria may have biofilm extracellular matrix (EM) components associated with them. These polysaccharides are similar in structure to EM of other pathogens that are known to have immunomodulatory properties (Vuong et al., 2004). Thus, Y.
What is the shape of the bubonic plague?
The disease is caused by a coccobacillus-shaped, gram negative bacterium referred to as Yersinia pestis.
Which of the following is characteristic 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.
What is the arrangement of Yersinia pestis?
Yersinia pestis KIM 10
| Names | Yersinia pestis KIM 10 |
|---|---|
| Host name | Homo sapiens |
| Cell arrangement | Singles |
| Sporulation | Nonsporulating |
| Metabolism | NA |
What is unique about Yersinia pestis?
The high pathogenicity of Y. pestis is to a significant extent due to the unique ability of the bacteria to overcome the defence mechanisms of both mammals and insects, thus ensuring their survival during the entire transmission cycle.
What is the life cycle of Yersinia pestis?
There are two cycles to the plague: Sylvatic Cycle and Urban Cycle. The Sylvatic Cycle is pre-human infection. Y. pestis, during this cycle, starts out in wild rodents which are then bit by fleas.
Does Yersinia pestis grow on blood agar?
It grows optimally at 28°C on blood agar or MacConkey agar, typically requiring 48 hours for observable growth. The colonies are initially much smaller than those of other Enterobacteriaceae and can therefore be easily overlooked ( Figure 5). The main characteristic of Y.
Is Yersinia pestis motile?
Motility: Non-motile (37 C and room temperature). Note:Y. pestis is the only species of Yersinia which is non-motile at room temperature).
Is Yersinia pestis stationary?
pestis reaches stationary phase. Additionally, all the sRNAs tested in Y. pestis require Hfq for their stability/expression which may explain the severe growth defect displayed by a hfq mutant of Y.
What type of cell wall does Yersinia pestis have?
Gram-negative cell wall
LPS. The Gram-negative cell wall structural molecule of LPS in Y. pestis is encoded by chromosomal genes. It differs from LPS of other enteric Gram-negative bacteria by not having an O side chain.
Does Yersinia pestis have flagella?
Yersinia pestis is nonmotile. Other species are nonmotile at 98.6°F (37°C) but motile at temperatures less than 86°F (30°C) by means of peritrichous flagella. They are aerobic and facultatively anaerobic, oxidase-negative and catalase-positive. They are nonlactose fermenters.
Does Yersinia pestis have a cell wall?
The Gram-negative cell wall structural molecule of LPS in Y. pestis is encoded by chromosomal genes. It differs from LPS of other enteric Gram-negative bacteria by not having an O side chain.
What is the incubation period for the Black Death?
Incubation period is typically 1–6 days. Symptoms and signs of the 3 clinical presentations of plague illness are as follows: Bubonic (most common)—rapid onset of fever; painful, swollen, and tender lymph nodes, usually inguinal, axillary, or cervical.
How fast does plague spread?
A person usually becomes ill with bubonic plague 2 to 8 days after being infected. The incubation period of septicemic plague is poorly defined but likely occurs within days of exposure. A person exposed to Yersinia pestis through the air would usually become ill in just 1 to 3 days.
Size – The size of Y. pestis is about 1.5 mm × 0.7 mm (micrometer). Arrangement Of Cells – Yersinia pestis is arranged singly, in pairs or in groups.
How to cultivate Yersinia pestis?
⇒ There are various culture media used for the cultivation of Yersinia pestis (Y. pestis) in the laboratory and most commonly the Nutrient Agar medium and Blood Agar medium is used, the other media are as follows – The liquid medium ( Nutrient Broth medium, TSB medium, etc.).
Is Yersinia pestis Gram positive or negative?
Gram Staining Reaction – Yersinia pestis is a Gram -ve (Negative) bacterium. In the microscopic view of Giemsa or Methylene blue-stained smear, shows bipolar staining (safety pin-like appearance) with the two ends densely stained and a clear central area.
What is the optimum temperature for Yersinia to grow?
⇒ Optimum temperature – The temperature for the growth of Yersinia pestis ranges from 2–45°C but the optimum temperature for the cultivation in the laboratory is 27°C and usually cultivated at this temperature in laboratories. However, the envelope develops best at 37° C.