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 – M1295/M1295I_HiCrome™ E. coli Agar

Recommended for the detection and enumeration of Escherichia coli in foods and water without further confirmation on membrane filter or by indole reagent.
推薦用於檢測和計數食品和水中的大腸桿菌,無需進一步確認膜過濾器或吲哚試劑。
Principle and Interpretation
HiCrome™ E. coli Agar is based on Tryptone Bile Agar to detect Escherichia coli in foods (1), where recovery of E. coli is faster, more reliable and accurate. Most of the E. coli strains can be differentiated from other coliforms by the presence of enzyme glucuronidase, which is highly specific for E. coli (2). Glucuronidase test is used increasingly for detection of E. coli in water and food microbiology as E. coli is an important indicator of fecal contamination in samples from the food processing and water purification plants. Other Escherichia spp. do not produce this enzyme (4). The chromogenic agent X-glucuronide used in this medium helps to detect glucuronidase activity of E. coli. E. coli cells absorb X-glucuronide and the intracellular lucuronidase enzyme splits the bond between the chromophore and the lucuronide. The released chromophore gives bluish green colouration to the E. coli colonies. Formulation of M1295I is in accordance with ISO (3).Tryptone and peptone special provide the nitrogenous compounds,carbon, amino acids, vitamins and other ssential growth nutrients to the organisms. Bile salts mixture inhibits gram-positive organisms. Sodium chloride and phosphates maintain osmotic balance and buffering action respectively.The surface of the plated medium is dried before use. Dilute food samples 1:5 or 1:10 with 0.1% (w/v) sterile Peptone Water (M028) and homogenize in a blender or a stomacher. Pipette 0.5 ml or 1.0 ml of the homogenized food sample on to the plate and spread with sterile glass spreader. Incubate the plates at 30°C for 4 hours and then at 44°C for 18 hours.
原理與解釋
HiCrome™大腸桿菌瓊脂基於胰蛋白腖膽汁瓊脂檢測食品中的大腸桿菌(1),其中大腸桿菌的回收更快,更可靠,更準確。大多數大腸桿菌菌株可以通過酶葡醣醛酸酶的存在與其他大腸桿菌區分,酶葡萄醣醛酸酶對大腸桿菌具有高度特異性(2)。葡萄醣醛酸酶試驗越來越多地用於檢測水和大腸桿菌中的大腸桿菌,因為大腸桿菌是一種 食品加工和淨水廠樣品中糞便污染的重要指標。其他埃希氏菌屬不產生這種酶(4)。在該培養基中使用的顯色劑X-葡糖苷酸有助於檢測大腸桿菌的葡醣醛酸糖苷酶活性。大腸桿菌細胞吸收X-葡糖苷酸,細胞內的葡醣醛酸酶分裂髮色團和葡萄醣醛酸之間的鍵。釋放的髮色團為大腸桿菌菌落提供藍綠色。 M1295I的配方符合ISO(3)。睾酮和蛋白腖特別為生物提供含氮化合物,碳,氨基酸,維生素和其他必需的生長營養素。膽汁鹽混合物抑制革蘭氏陽性生物。氯化鈉和磷酸鹽分別保持滲透平衡和緩衝作用。電鍍介質的表面在使用前乾燥。用0.1%(w / v)無菌蛋白腖水(M028)稀釋食物樣品1:5或1:10,並在攪拌器或stomacher中均化。移取0.5ml或1.0ml均質食品樣品到板上並用無菌玻璃塗佈器塗抹。將板在30℃孵育4小時,然後在44℃孵育18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。