HiCrome® Bacillus Agar Plate

Principle And Interpretation

Majority of Bacillus species apparently have little or no pathogenic potential and are rarely associated with disease in human or lower animals. The principal exception to this are Bacillus anthracis, the agent of anthrax, and Bacillus cereus, but a small number of other species, particularly those of the B.subtilis group, have been implicated in food poisoning and other human and animal infections (7). Bacillus cereus causes food poisoning due to consumption of contaminated rice (2,5,10), other starchy foods such as potato, pasta and cheese have also been implicated, eye infections and a wide range of other clinical conditions like abscess formation, meningitis, septicemia and wound infection.
HiCrоmетм Ваcillus Agar is based on the formulation of MYP Agar formulated by Mossel et al (6) used for enumeration of Bacillus cereus and Bacillus thuringiensis when present in large number in certain foodstuffs
The medium contains peptone and HM extract, which provide nitrogenous, carbonaceous compounds, long chain amino acids, vitamins and other essential growth nutrients. Mannitol serves as the fermentable carbohydrate, fermentation of which can be detected by phenol red. The chromogenic mixture present in the medium is cleaved by the enzyme beta-glucosidase found in B.cereus resulting in the formation of blue colonies. B.thuringiensisalso grows as blue/green colonies on this medium as B.cereus and B.thuringiensis are biochemically identical, however B.cereus shows flat colonies with distinct blue centers, while B. thuringiensis shows irregular margins. Bacillus Selective supplement (FD324). inhibits the growth of other Bacillus and contaminating microflora.