Improved diagnostic media for isolating, identifying, and classifying Enterobacteriaceae comprise an effective amount of isopropyl-beta-D-thiogalactopyranoside in order to reduce the incidence of false lactose negative determinations and to differentiate between lac inducible and lac constitutive bacteria.
A medium for lysine decarboxylation test comprises 2 to 7 g of yeast extract, 1 to 5 g of peptone, 0.5 to 1.5 g of glucose, 0.3 to 1 g of monalkali metal dihydrogen phosphate, 10 to 40 g of L-lysine mineral acid salt, 0.01 to 0.08 of 5'-pyridoxalphosphoric ester, and 0.04 to 0.1 g of a pH indicator, and has a pH value in the range of 5.5 to 6.5 when dissolved in 2 liter of water.
A test for the detection of bacteria of the genuses Salmonella and Serratia and distinguishing them from the genuses Proteus and Providencia carried out in the presence of a diazonium salt and a synthetic enzymatic substrate in the form of an ester having an aliphatic chain of 7 to 10 carbon atoms. Two reactions may be effected in the same reactive medium. The test may be associated with other tests such as the .beta.-glucosidase, .beta.-galactosidase and .beta.-glucuronidase research tests making it possible to apply it simultaneously to the detection of bacteria belonging to other genuses: Kliebsiella, Enterobacter, Escherichia.
A small number of microorganisms can be rapidly detected or determined by means of a fluorescence analysis method using specific umbelliferone derivatives such as 4-methylumbelliferyl phosphate and 4-methyl umbelliferyl galactoside, and this detecting method is applicable for a microbial inspection on sanitary quality of various kind of food, beverage, water and toilet article, or for a clinical inspection on a microbial infection.
5527667 - Water sample viral contamination detection system - Owned by Virginia Polytechnic Institute and State University (Blacksburg, VA) Virginia Tech Intellectual Properties, Inc. (Blacksburg, VA) The Center for Innovative Technology (Herndon, VA)
Viral contamination in water samples is detected using a medium which includes both a substrate for .beta.-galactosidase and E. coli with elevated levels of intracellular .beta.-galactosidase. The substrate is chosen to undergo a detectable change (e.g., colorimetric, fluorometric, photometric, etc.) upon cleavage by .beta.-galactosidase. A water sample to be tested for viral contamination is added to the medium. If coliphages are present in the water sample, they will infect, multiply within, and subsequently lyse the E. coli host. Lysis of the E. coli will allow the release of the intracellular .beta.-galactosidase into the media, whereupon the enzyme will cleave the substrate for a detectable reaction. In one particular application, a colorimetric reagent that serves as a substrate for .beta.-galactosidase is dissolved or dispersed within an agar medium, and in another particular application, a colorimetric reagent that serves as a substrate for .beta.-galactosidase is dissolved or dispersed within a liquid medium. Color changes which result from lytic cell infection of the E. coli hosts are easily monitored by researchers or laboratory technicians. The presence of coliphages in a water sample is indicative of the presence of harmful human and animal enteric viruses in the water.
The invention relates to a method of bacteriological analysis for the selective detection of Salmonella and a medium for its implementation. The method is based on the specific capacity of Salmonella to ferment glucuronic acid or one of its salts, and not to produce .beta.-galactosidase. The medium comprises a nutrient which is metabolized by the bacteria, a chromogenic or fluorigenic compound capable of being hydrolyzed by the enzyme .beta.-galactosidase, glucuronic acid or one of its salts and a pH indicator.
