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Learn about the symptoms, diagnosis, treatment, and prevention of plague, a bacterial infection caused by Yersinia pestis. See images of buboes, the enlarged lymph nodes characteristic of bubonic plague.
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.)
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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.
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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 ...
- R. Barbieri, M. Signoli, D. Chevé, C. Costedoat, S. Tzortzis, G. Aboudharam, D. Raoult, M. Drancourt
- 2020
- Laboratory Diagnosis of Plague
- Culture
- Antigen Detection
- Serological Techniques
- Other Methods
- Typing
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Specimen Choice of a sample depends on the type of plague. Commonly used samples are; pus, fluid aspirated from buboes, sputum, or blood. If a delay in transportation is likely, Cary-Blair transport mediumcan be used. Direct microscopy 1. Gram staining reveals the presence of pus cells and Gram-negative (pink) single or short-chained pleomorphic co...
Y. pestisis a member of the Enterobacteriaceae family. It is aerobic and facultatively anaerobic. The optimum temperature for growth (unlike most pathogens) is 27°C. It is not fastidious and grows on ordinary media. Y. pestisgrows well in nutrient-rich broth (such as brain heart infusion, trypticase soy or nutrient broth) or agar medium like (Blood...
F1 antigen is detected from bubo aspirate or sputum by direct immunofluorescence test, ELISA, or immunochromatographic test (ICT)by using monoclonal antibodies.
Antibodies against the F1 antigen can be detected by passive hemagglutination or complement fixation testor ELISA. The use of paired sera and the presence of a four-fold rise in titer confirms the diagnosis. The presence of antibodies provides limited diagnostic value, as the diagnosis is retrospective but may help as an epidemiological marker.
Rapid diagnostic tests, Immunofluorescence antibody test, Real-time Polymerase Chain reaction (PCR) can be used to identify Yersinia isolates to species level. PCR is available targeting gene coding F1 antigen, pesticin gene, and the plasminogen activator gene.
Typing and differentiation between strains of Yersiniaspecies can be achieved using a range of molecular techniques eg multiple-locus variable-number tandem-repeat analysis, pulsed-field gel electrophoresis (PFGE), whole-genome sequencing (WGS), etc. Biotyping is done based on glycerol fermentation and nitrate reduction.
Learn about the gram-negative rod that causes plague, a fatal zoonotic disease. See how to identify it by gram staining, Giemsa staining, culture, and biochemical tests.
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...
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.
