HIMEDIA HiCrome 顯色培養基(/產色培養基/呈色培養基)

顯色培養基(/產色培養基/呈色培養基)
                                 ( Chromogenic / Fluorogenic Culture Media )


顯色培養基一般是在培養基中加入檢測特定菌種的特殊性底物。
        (一種或多種顯色劑(目測) 或 熒光顯色劑(紫外燈照射觀察) )
該特殊性底物 與 特定微生物自身代謝產生的酶 會產生顯色(產色)情形,
藉此直接觀察菌落顏色即可對菌種做出鑑定,
其反應的靈敏度和特異性大大優於傳統培養基。

顯色培養基通常為乾粉狀,容易儲存。
加蒸餾水溶解後,部分產品無須高壓滅菌,培養時間依具體培養基而定,
通常是18-24小時,比傳統時間顯著縮短。

HiMedia – M1832_HiCrome™ Coliform Agar Modified

Recommended for the simultaneous detection of Escherichia coli and thermotolerent coliforms in water, milk, dairy products and other food samples.
推薦用於同時檢測水,牛奶,乳製品和其他食品樣品中的大腸桿菌和耐熱大腸桿菌。
Principle and Interpretation
HiCrome™ Coliform Agar Modified is a selective medium recommended for the simultaneous detection of E.coli and thermotolerant coliforms in water and food samples (4). Peptone special and yeast extract provide the neccssary nitrogen compound, carbon, vitamins and also some trace ingredients required for the growth of organisms. The phosphates buffer the medium well. Magnesium sulphate helps colour development. Bile salts inhibits gram-positive organisms. Sodium chloride maintains osmotic balance. The chromogenic mixture contains two chromogenic substrates, which enables the detection of two specific enzymes, b-galactosidase and b-glucoronidase. b-galactosidase produced by coliforms cleaves one chromogen, resulting in the pink colouration of coliform colonies. The enzyme b-glucuronidase produced by E. coli, cleaves X-glucuronide. E.coli forms dark blue to violet coloured colonies due to cleavage of both the chromogens (1, 2, 3). E.coli strains that are b-glucoronidase negative (serotype O157:H7) produce pink coloured colonies. Other gram negative bacteria able to grow at (44±0.5)°C produce white or colourless colonies. Transfer 1 ml of product to analyse and its tenfold dilutions to sterile Petri plates. Pour 12 ml of medium, mix well and allow to solidify. Overlay with 4 ml of medium, allow to solidify and incubate at 43-45°C for 18-24 hours.
原理與解釋
HiCrome™Coliform Agar Modified是一種選擇性培養基,推薦用於同時檢測水和食物樣品中的大腸桿菌和耐熱大腸桿菌(4)。蛋白腖特殊酵母提取物提供了必需的氮化合物,碳,維生素以及生物生長所需的一些微量成分。磷酸鹽緩衝介質。硫酸鎂有助於顏色的發展。膽汁鹽抑制革蘭氏陽性菌。氯化鈉保持滲透平衡。 顯色混合物含有兩種生色底物,能夠檢測兩種特定的酶,即β-半乳糖苷酶和β-葡萄醣醛酸酶。由大腸桿菌產生的β-半乳糖苷酶切割一種色原體,導致大腸菌落的粉紅色。由大腸桿菌產生的酶β-葡醣醛酸糖苷酶切割X-葡糖苷酸。 由於兩種色原(1,2,3)的切割,大腸桿菌形成深藍色至紫色的菌落。 b-葡萄醣醛酸酶陰性的大腸桿菌菌株(血清型O157:H7)產生粉紅色的菌落。其他能夠在(44±0.5)℃生長的革蘭氏陰性菌產生白色或無色菌落。 轉移1ml產物進行分析,將其十倍稀釋至無菌培養皿中。倒入12毫升培養基,充分混合併使其固化。 用4ml培養基覆蓋,使其固化並在43-45℃下孵育18-24小時。
HiMedia Laboratories 的顯色培養基 產品以HiCrome為開頭命名
       相較於 法國Chromagar、德國Merck、英國Oxoid、美國Remel 其他顯色培養基品牌,
       HiMedia 顯色培養基產品 更多元,更豐富,品質優越。