Device, composition and method for identifying microorganisms

A composition for identifying or testing a microorganism by growing a culture of the microorganism in contact therewith, said composition consisting essentially of an aqueous solution containing:

• (1) from about 0.0001% to 0.1% by weight of a tetrazolium compound which undergoes a substantially irreversible change in color upon being reduced to a formazan compound, (2) from about 2 to 500 millimoles per liter of a biodegradable test substrate compound which, when catabolized by a microorganism, will engender reduction of the tetrazolium compound to a formazan compound, (3) a buffer in an amount sufficient to maintain the pH of the composition at a level which is within the range of 4.5 to 12.5 and which enables microorganism culture growth without engendering or preventing reduction of the tetrazolium compound to a formazan compound, and (4) a microorganism nutrient in a concentration such that no one catabolizable ingredient thereof is present in an amount greater than one millimole per liter or greater than 1/100 the amount of the test substrate compound.

A method for identifying or testing a microorganism comprising growing a culture of the microorganism in contact with each of a plurality of compositions each consisting essentially of an aqueous solution containing:

• (1) an oxidation-reduction indicator which substantially irreversibly undergoes a change in color upon being reduced, (2) a biodegradable test substrate compound which, when catabolized by a microorganism, will engender reduction of said indicator, (3) a buffer to maintain the pH of the composition at a level which enables microorganism culture growth without engendering or preventing reduction of said indicator, and (4) a microorganism nutrient in a concentration sufficient to support microorganism culture growth without engendering reduction of said indicator, the test substrate in each of said compositions being different than the test substrate in each of the other compositions, said compositions being otherwise substantially identical to each other.

A device for identifying or testing a microorganism comprising a container having a separate compartments, each of a plurality of said compartments having therein a composition consisting essentially of an aqueous solution containing (1) an oxidation-reduction indicator which substantially irreversibly undergoes a change in color upon being reduced, (2) a biodegradable test substrate compound which, when catabolized by a microorganism, will engender reduction of said indicator, (3) a buffer to maintain the pH of the composition at a level which enables microorganism culture growth without engendering or preventing reduction of said indicator and (4) a microorganism nutrient in a concentration sufficient to support microorganism culture growth without engendering reduction of said indicator, the composition in each of said plurality of compartments containing a different test substrate compound than that in the compositions in the other of said plurality of compartments but the compositions in all of said plurality of compartments being otherwise substantially identical.

A device for identifying or testing a microorganism comprising a container having an upper portion containing a nutrient solution and adapted to receive a microorganism culture for growth therein, and a lower portion having a plurality of separate compartments each of which is separated from said upper portion by a barrier which is liquid impermeable but which is breachable to allow said solution with a microorganism culture therein to flow into said compartments, each of said compartments having therein a composition containing an oxidation-reduction indicator which undergoes a change in color upon being reduced and biodegradable test substrate compound which, when catabolized by a microorganism, engenders reduction of said indicator, the composition in each of said compartments containing a different test substrate compound than that in the compositions in the other of said compartments and the concentration of said nutrient in said nutrient solution being sufficient to support microorganism culture growth without engendering reduction of said indicator when said nutrient solution with a microorganism culture therein comes into contact with the compositions in said compartments.

A method for identifying or testing a microorganism comprising growing a culture of the microorganism in a nutrient solution and then bringing said nutrient solution with the microorganism culture therein into contact with each of a plurality of compositions each of which consists essentially of an aqueous solution containing an oxidation-reduction indicator which substantially irreversibly undergoes a change in color upon being reduced, and a biodegradable test substrate compound which, when catabolized by a microorganism, will engender reduction of the indicator, the test substrate compound in each of said compositions being different than the test substrate compound in each of the other of the compositions and the concentration of the nutrient in said nutrient solution being sufficient to support microorganism culture growth withut engendering reduction of the indicator when said nutrient solution with the microorganism culture therein contacts said compositions.