Process and apparatus for analyzing specimens for the presence of microorganisms therein

US3963355A · kind A · utility

Assignee

• McDonnell Douglas Corporation · US

Inventors

• Clifton Aldridge · Creve Coeur, US
• Paul W. Jones · Windom, US
• Sandra F. Gibson · Chesterfield, US
• Richard D. Vannest · Holden, US
• James T. Holen · Mundelein, US
• George F. Keyser · Chesterfield, US
• Michael C. Meyer · Belleville, US

Key dates

• Filing date: Apr 16, 1974
• Grant date: Jun 15, 1976
• Expiry date: Apr 16, 1994

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S435/922
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Microorganisms in a specimen are detected, identified, and enumerated by introducing the specimen into a sampling cartridge and diluting the specimen with a known volume of water within the cartridge. The cartridge has a manifold and several cassettes attached to the manifold. Each cassette contains a serpentine flow channel having a series of filters therein and a detection cell located downstream from each filter. The flow channel in each cassette also contains a culture medium which is freeze dried and is highly selective in the sense that it promotes the growth of one type of microorganism, but not others. The mixture of the specimen and water flows from the manifold into the flow channel of each cassette where it rehydrates the culture medium therein and further flows through the filters. Each filter removes a known proportion of the microorganisms from the mixture of specimen, water and medium, thereby effecting a serial dilution. After the cassettes are heated to incubate the microorganisms, the detection cells are observed for growth of the microorganisms therein which is manifested in a change in the light transmitting characteristics of the mixtures within the cells. This…