Cultural Characteristics of Bacillus cereus 5/5 (2)




Cultural Characteristics of Bacillus cereus

Cultural Characteristics of Bacillus cereus

  1. Most Bacillus spp grow readily on nutrient agar or peptone media.
  2. The optimum temperature for growth varies from 20°C to 40°C, mostly 37°C.
  3. B. cereus is mesophilic and is capable of adapting to a wide range of environmental conditions.
  4. On Nutrient Agar at 37°C, it forms large (2-5 mm) grey-white, granular colonies with a less wavy edge and less membranous consistency.
  5. On 5% sheep blood agar at 37°C, cereus colonies are large, feathery, dull, gray, granular, spreading colonies and opaque with a rough matted surface and irregular perimeters.
  6. On blood agar, it is beta-hemolytic.
  7. Colony perimeters are irregular and represent the configuration of swarming from the site of initial inoculation, perhaps due to cereus swarming motility.
  8. In some instances smooth colonies develop either alone or in the midst of rough colonies.
  9. When grown apart from the initial inoculum, smooth colonies are surrounded by a uniform zone of beta-hemolysis framing the centrally situated colony.
  10. The MYP agar has been the standard media for plating  cereus, but it has little selectivity so background flora is not inhibited and can mask the presence of B. cereus. Bcereuscolonies are usually lecithinase-positive and mannitol-negative on MYP agar.
  11. Bacara is a chromogenic selective and differential agar that promotes the growth and identification of  cereus, but inhibits the growth of background flora. Bacillus cereus colonies turn pink-orange with an opaque halo.
  12. The chromogenic agar has been suggested for the enumeration of  cereus group as a substitute for MYP. Typical colonies will grow as pink-orange uniform colonies surrounded by a zone of precipitation.

References

  1. Bacillus cereus HiCynth™ Agar Base. HiMedia Laboratories Pvt. Ltd.
  2. S Fazlani, M Abubakar, S Shah, M ul Hassan, M Arshed. Bio-Morphological Characteristics of Bacterial Species Identified from Mastitic Milk Samples of Camel. The Internet Journal of Veterinary Medicine. 2008 Volume 6 Number 1.
  3. https://catalog.hardydiagnostics.com/cp_prod/Content/hugo/Bacillus.htm
  4. http://www.antimicrobe.org/b82.asp
  5. https://microbewiki.kenyon.edu/index.php/Bacillus_cereus
  6. http://www.ncbi.nlm.nih.gov/pubmed/25528535
  7. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2863360/
  8. http://www.biomerieux-industry.com/food/bacillus-cereus-culture-media
  9. http://www.ppdictionary.com/bacteria/gpbac/cereus.htm
  10. http://www.tgw1916.net/Bacillus/cereus.html
  11. https://sites.google.com/site/allmicrobiologysite/medical-microbiology-ii/summary-of-bacterial-pathogens/bacillus-cereus
  12. http://academic.pgcc.edu/~kroberts/web/colony/colony.htm
  13. http://www.microbiologyinpictures.com/bacteria-micrographs/gram-stain/gram-positive/bacillus-cereus.html
  14. https://modmedmicrobes.wikispaces.com/B.Cereus
  15. http://www.fda.gov/Food/FoodScienceResearch/LaboratoryMethods/ucm070875.htm

Cultural Characteristics of Bacillus cereus

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The Author

Sagar Aryal

Sagar Aryal

I am Sagar Aryal, a passionate Microbiologist and the Scientific Blogger. I did my Master's Degree in Medical Microbiology and currently working as a Lecturer at Department of Microbiology, St. Xavier's College, Kathmandu, Nepal. I am particularly interested in research related to Medical Microbiology and Virology.

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  1. I have seen gram positive bacilli growing in mannitol salt agar, do you know what species are capable of this?

  2. Can Bacillus cereus be non haemolytic in blood agar?

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