HiMedia – M1651 HiCrome™ Bacillus Agar

Principle and Interpretation
Majority of Bacillus species apparently have little or no pathogenic potential and are rarely associated with disease in humans or lower animals. The principal exception to this are Bacillus anthracis, the agent of anthrax, and Bacillus cereus. However a number of other species, particularly those of the B. subtilis group, have been implicated in food poisoning and other human and animal infections (4). Bacillus cereus causes food poisoning due to consumption of contaminated rice (2, 1, 5) 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. HiCrome™ Bacillus Agar is based on the formulation of MYP Agar formulated by Mossel et al (2) 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 and carbonaceous compounds, long chain amino acids, vitamins and other growth nutrients. Mannitol serves as the fermentable carbohydrate, fermentation of which can be detected by phenol red. Mannitol fermenting organisms like B. megaterium yield yellow coloured colonies. The chromogenic mixture present in the medium is cleaved by the enzyme b-glucosidase found in B. cereus resulting in the formation of blue colonies. B. thuringiensis also grows as blue/green colonies on this medium as B. cereus and B. thuringiensis are biochemically identical. If selective isolation of B. cereus or B. thuringiensis is required aseptically add Bacillus Selective Supplement (FD324).

原理與解釋
大多數芽孢桿菌物種顯然具有很少或沒有致病潛力，並且很少與人類或低等動物的疾病相關。其主要的例外是炭疽桿菌炭疽桿菌和蠟狀芽孢桿菌。然而，許多其他物種，特別是枯草芽孢桿菌群的物種，已經涉及食物中毒和其他人類和動物感染（4）。蠟樣芽孢桿菌因食用受污染的大米而導致食物中毒（2,1， 5）其他澱粉類食物如馬鈴薯，意大利面和奶酪也有牽連，眼部感染和廣泛的其他臨床病症如膿腫形成，腦膜炎，敗血症和傷口感染。 HiCrome™芽孢桿菌瓊脂基於Mossel等人（2）配製的MYP瓊脂的配方，用於在某些食品中大量存在時對蠟狀芽孢桿菌和蘇雲金芽孢桿菌進行計數。該培養基含有蛋白腖和HM提取物，提供含氮和含碳化合物，長鏈氨基酸，維生素和其他生長營養素。甘露醇用作可發酵的碳水化合物，其發酵可以通過酚紅檢測。甘露醇發酵生物如巨大芽孢桿菌產生黃色菌落。存在於培養基中的生色混合物被蠟狀芽孢桿菌中發現的酶β-葡糖苷酶切割，導致藍色菌落的形成。 B. 蘇雲金芽孢桿菌也在該培養基上生長為藍/綠色菌落，因為蠟狀芽孢桿菌和蘇雲金芽孢桿菌在生物化學上是相同的。如果需要選擇性分離蠟狀芽孢桿菌或蘇雲金芽孢桿菌，則無菌添加芽孢桿菌選擇性補充劑（FD324）。