Bacillus Cereus Tests

by on February 1st, 2011
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Bacillus cereus is a facultative aerobe which forms spores. It is often pathogenic to humans because of incorrectly prepared food. It is unique in that the culture is gram-positive when young, but gram-negative when older. The first sign of infection with this organism is emesis. It is somewhat similar to Clostridium. B. Cereus is not an opportunistic pathogen. The spore form is the pathogenic part, as it releases an enterotoxin. Enterotoxin means its primary area of infection is the intestine, although it inhabits the entire GI tract. B. Cereus is extremely difficult to identify. Bacillus strains often can be found by the
following algorithm:
Acid produced by mannitol will be negative.
This specific strain can be found with: Phenol red glucose broth Nitrate broth Lysozyme broth There are additional tests needed that VirtuaLabs do not offer. It is commonly (and perhaps wrongly) often attributed to rice. This is due to isolated incident, but rice is indeed a medium for growth.


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