Test media for identifying and differentiating general coliforms and Escherichia coli bacteria

A test medium for detecting the presence of general coilforms having .beta.-galactosidase but not .beta.-glucuronidase activity, said test medium comprising:

• a nutrient base medium, said nutrient base medium being a solid or gel;
• a chromogenic .beta.-galactosidase substrate forming an insoluble compound of a first color upon reacting with .beta.-galactosidase, said chromogenic .beta.-galactosidase substrate being selected from the group consisting of 6-chloroindolyl-.beta.-D-galactoside, 4,6-dichloroindolyl-.beta.-D-galactoside, 6,7-dichloroindolyl-.beta.-D-galactoside, 4,6,7-trichloroindolyl-.beta.-D-galactoside and salts thereof;
• and
• a chromogenic .beta.-glucuronidase substrate for forming a second water insoluble compound of a second color upon reacting with .beta.-glucuronidase;
• wherein said chromogenic .beta.-glucuronidase substrate is 5-bromo-4-chloro-3-indolyl-.beta.-D-glucuronide or indoxyl-.beta.-D-glucuronide.

A test medium for detecting the presence of general coilforms and E. coli having .beta.-glucuronidase activity, said test medium comprising:

• a nutrient base medium, said nutrient base being a solid or gel;
• a chromogenic .beta.-glucuronidase substrate forming an insoluble compound of a first color upon reacting with .beta.-glucuronidase, said chromogenic .beta.-glucuronidase substrate being selected from the group consisting of 6-chloroindolyl-.beta.-D-glucuronide, 4,6-dichloroindolyl-.beta.-D-glucuronide, 6,7-dichloroindolyl-.beta.-D-glucuronide, 4,6,7-trichloroindolyl-.beta.-D-glucuronide and salts thereof;
• and
• a chromogenic 5-bromo-4-chloro-3-indolyl-.beta.-D-galactopyranoside substrate for forming a water insoluble compound of a second color upon reacting with .beta.-galactosidase.