HiMedia – M1426_M-E. coli Broth

Principle and Interpretation
M-E.coli Broth is used for detection and differentiation of Escherichia coli and coliforms in water samples using membrane filter technique. It is based on Tryptone Bile Agar used for detection of Escherichia coli in foods (1) where recovery of Escherichia coli is faster, more reliable and accurate. The water sample is filtered through membranes and then placed on pad saturated with M-E.coli Broth and incubated at 37°C in sealed Petri plates. 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 (3). The medium contains chromogenic mixture which helps to detect glucuronidase activity of Escherichia coli (2). This specific enzyme differentiates Escherichia coli from other coliforms. Escherichia coli cells split the chromogenic mixture with the help of the enzyme glucuronidase to give blue to green colouration to the colonies. Coliforms other than Escherichia coli turn red as they reduce TTC (2,3,5-triphenyl tetrazolium chloride). Thus, the resulting colour distinction allows simple interpretation of test without further confirmation. Tryptone provides nitrogen and carbon source, long chain amino acids, vitamins and other essential growth nutrients to the organisms. Bile salt mixture inhibit gram-positive organisms.

原理與解釋
M-E.coli Broth用於使用膜過濾技術檢測和分離水樣中的大腸桿菌和大腸桿菌。 它基於用於檢測食品中大腸桿菌的胰蛋白腖膽汁瓊脂（1），其中大腸桿菌的回收更快，更可靠和準確。 將水樣過濾通過膜，然後置於用M-大腸桿菌肉湯飽和的墊上，並在密封的培養皿中於37℃溫育。葡萄醣醛酸酶測試越來越多地用於檢測水和食品微生物中的大腸桿菌，因為大腸桿菌是食品加工樣品中糞便污染的重要指標 和淨水廠。其他埃希氏菌屬不產生這種酶（3）。該培養基含有顯色混合物，有助於檢測大腸桿菌的葡萄醣醛酸酶活性（2）。這種特異性酶可以區分大腸桿菌和其他大腸桿菌。 大腸桿菌細胞在葡萄醣醛酸酶的幫助下分裂顯色混合物，使菌落呈藍色至綠色。除大腸桿菌外的大腸桿菌在減少TTC（2,3,5-三苯基四唑氯化物）時變紅。因此，由此產生的顏色區分允許簡單地解釋測試而無需進一步確認。 胰蛋白腖為生物提供氮和碳源，長鏈氨基酸，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。