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Plague is caused by the gram-negative bacterium Yersinia pestis. Yersinia (formerly Pasteurella) pestis is a short bacillus that often shows bipolar staining (especially with Giemsa stain) and may resemble a safety pin. Massive human epidemics (eg, the Black Death of the Middle Ages, an epidemic in Manchuria in 1911) have occurred.
Dec 9, 2020 · The Gram-negative bacterium Yersinia pestis is responsible for deadly plague, a zoonotic disease established in stable foci in the Americas, Africa, and Eurasia. Its persistence in the environment relies on the subtle balance between Y. pestis -contaminated soils, burrowing and nonburrowing mammals exhibiting variable degrees of plague ...
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Dec 26, 2017 · YERSINIA PESTIS, A PLAGUE PATHOGEN. Y. pestis, a Gram-negative bacterium, belongs to the family Enterobacteriaceae. It was first isolated during the third pandemic plague in Hong Kong by Alexandre Yersin. In addition to Y. pestis, the genus Yersinia includes Y. pseudotuberculosis and Y. enterocolitica, which are also associated with human ...
Gram stain: Pinpoint, gray-white and translucent at 24h on BAP; 1-2 mm, gray-white to slightly yellow and opaque after 48h. May have a raised, irregular “fried egg” appearance after 48- 72h. (This is not unique to Y. pestis but can be a useful characteristic, if observed.)
Yersinia pestis (Y. pestis; formerly Pasteurella pestis) is a gram-negative, non-motile, coccobacillus bacterium without spores that is related to both Yersinia enterocolitica and Yersinia pseudotuberculosis, the pathogen from which Y. pestis evolved and responsible for the Far East scarlet-like fever.
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.
Apr 3, 2019 · The etiological agent of plague is the Gram-negative bacterium Yersinia pestis [ 2 ], discovered by the Institut Pasteur, bacteriologist Alexandre Yersin during a plague outbreak in Hong Kong...
Dec 29, 2023 · Gram staining reveals the presence of pus cells and Gram-negative (pink) single or short-chained pleomorphic coccobacilli with rounded ends surrounded by a capsule. Wayson or Giemsa staining demonstrates the typical bipolar or safety pin appearance.
Now, Yersinia pestis has a thin peptidoglycan layer, so it doesn’t retain the crystal violet dye during Gram staining. Instead, like any other Gram-negative bacteria, it stains pink with safranin dye.
Gram stain morphology: Gram-negative rods, 0.5 x 1-2 mm. Colony morphology: Slow growing, pinpoint colonies after 24h; Colonies are 1-2mm, gray=white to slightly yellow and opaque on BAP after 48 h; non-lactose fermenter on MAC/EMB; growing both At 25-28 0C and at 35-37 0C. Specimen: Blood, sputum, or lymph node aspirate. WARNING:
