Method for testing and identifying microorganisms

• US 4,235,964 A
• Filed: 09/28/1978
• Issued: 11/25/1980
• Est. Priority Date: 09/28/1978
• Status: Expired due to Term

• Current Assignee: Barry R. Bochner
• Original Assignee: Barry R. Bochner
• Inventors: Bochner, Barry R.
• Primary Examiner(s): Warden, Robert J.
• Application Number:
  US05/946,884
• Time in Patent Office: 789 Days
• Field of Search: 435/34, 435/243, 435/253, 435/801, 435/35, 435/36, 435/37, 435/38
• US Class Current: 435/34
• CPC Class Codes: C12M 41/36 of biomass, e.g. colony counters or by turbidity measurements electrooptical investigation of individual particles G01N15/14, flow cytometers G01N15/1404
• CPC Class Codes: C12Q 1/04 Determining presence or kind of microorganism; Use of selective media for testing antibiotics or bacteriocides; Compositions containing a chemical indicator therefor C12Q1/6897 takes precedence
• CPC Class Codes: C12Q 2304/24 Tetrazolium; Formazan
• CPC Class Codes: G01N 2333/21 from Pseudomonadaceae (F)
• CPC Class Codes: G01N 2333/255 Salmonella (G)

Abstract

In accordance with the invention there is provided a method for identifying or testing an anaerobic microorganism wherein an aqueous suspension of a culture of the microorganism having a culture density of about 2×10⁸ cells/ml, is brought into contact with 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, said aqueous suspension containing nutrient in a concentration sufficient to support microorganism culture growth without engendering reduction of the indicator when said suspension contacts said solution, and said suspension also containing a compound which reduces O₂ but does not reduce the indicator.

Claims

1. A method for identifying or testing a microorganism comprising preparing a suspension of a culture of the microorganism in a nutrient solution to a culture density of about 2×

10⁸ cells/ml, and then bringing said suspension into contact with 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 concentration of nutrient in said suspension being insufficient to engender reduction of the indicator when said suspension contacts said solution, said suspension containing a compound which reduces O₂ but which does not reduce the oxidation-reduction indicator and which is present in said suspension in an amount sufficient to reduce all the O₂ therein, at least one of said suspension and said solution containing a buffer to maintain the pH at from about 4.5 to 8 while said suspension is in contact with said solution.

2. A method for identifying or testing a microorganism comprising preparing a suspension of a culture of the microorganism in a nutrient solution to a culture density of at least 2×

10⁸ cells/ml, said suspension having a pH from about 4.5 to 8 and being substantially sealed from the ambient atmosphere, and then unsealing and bringing said suspension into contact with a solution which is exposed to oxygen from the ambient atmosphere, which has a pH of from about 4.5 to 8, and which contains 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 concentration of the nutrient in said suspension being insufficient to engender reduction of the indicator when said suspension contacts said solution, said suspension containing a compound which reduces O₂ but which does not reduce the oxidation-reduction indicator at a pH of from 4.5 to 8 in the presence of O₂, said compound which reduces O₂ being present in said suspension in an amount sufficient to reduce all the O₂ therein.

3. A method as set forth in claim 2 wherein said oxidation-reduction indicator is triphenyl tetrazolium chloride and wherein said compound which reduces O₂ is glutathione and is present in said suspension in an amount of at least about 5 millimoles per liter.