Abstract: A medium for determining Escherichia coli sensitivity to a pre-selected antimicrobial agent. The medium contains nutrient sources, inhibitors to inhibit growth of gram-positive and of other gram-negative micro-organisms, and an indicator which will show metabolic activity or lack thereof by E. coli in the medium, and a specific antimicrobial agent whose effectiveness against E. coli is being tested. If a given agent is effective against E. coli when E. coli is added to the medium containing that agent, the medium will remain clear. If the specific agent is ineffective against E. coli the color of the medium containing E. coli and that agent will change to blue as the E. coli metabolizes in the medium and produces acid.

Abstract: The sensitivity of Klebsiella and Enterobacter organisms to preselected antibiotics is determined with a medium consisting essentially of a nutrient source for Klebsiella and Enterobacter organisms, about 0.01 to about 0.03 g/l 2,4 dinitro phenyl hydrazone of .alpha.-Ketoglutaric acid, about 3.5 to about 6 g/l sodium desoxycholate and the preselected antibiotic.

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.

Abstract: A broth medium for the detection of Group D enterococci in urine. The medium employs neomycin sulfate to inhibit growth of Staphylococcus aureus, potassium tellurite to inhibit growth of gram-negative organisms, and ferric ammonium citrate and esculin hydrolysate indicators.

Abstract: A broth medium for the detection of Candida yeasts, Saccharamyces cerevisiae, Torulopsis glabrata, and Aspergillus niger in urine. The medium employs chloramphenicol and potassium tellurite to inhibit the growth of gram-positive and gram-negative organisms. The medium also uses reduced aniline blue biological pH indicator.

Abstract: A broth medium for the detection of Citrobacter freundii in urine. The medium employs palatinose and rhamnose as carbon sources to enhance the growth of the organism. A combination of .alpha.-hydroxy-2',4,4'-trichlorodiphenyloxide and Brilliant Green are employed to inhibit the growth of Aeromonas and Klebsiella organisms. Gram positive organisms are inhibited by surfactants, such as Bile Salts mixture. The presence of C. freundii is detected by means of precipitation and a consequent change in the light transmitting properties of the medium.

Abstract: A broth medium for the detection of Klebsiella, specifically Klebsiella pneumoniae and Enterobacter in urine. The medium employs 3-(.alpha.-acetonylbenzyl)-4-hydroxycoumarin and 2,4 dinitro-phenyl hydrazone of .alpha.-Ketoglutoric acid to inhibit growth of Escherichia Coli organisms and to promote growth of Klebsiella. This medium also has a pH of about 8.0 to inhibit other organisms which grow under more neutral conditions.

Abstract: A broth medium for the detection of Pseudomonas aeruginosa in urine. The medium employs cetyl trimethylammonium bromide to inhibit growth of unwanted organisms that normally give positive results in tests for P. aeruginosa.

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.

Abstract: A process for determining the susceptibility of microorganisms to antibiotics involves introducing a diluted specimen into discrete quantities of a selective culture medium which favors a specific microorganism in that the microorganism is sustained by the medium and when so sustained will change the optical characteristics of the medium. Only the specific microorganism will alter the optical characteristics. Some of the discrete quantities are blended with known antibiotics, while at least one is not. If the specimen contains the microorganisms favored by the selective medium, the optical characteristics of the discrete quantity of pure selective medium, that is the one without antibiotics, will change. If the antibiotics in any of the other discrete quantities are ineffective against the favored microorganisms, the optical characteristics of those quantities will likewise change.