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This medium is based on the formula described by Kupferburg, Johnson and Sprince for the selective isolation of Trichomonas spp. The medium is selective due to the inclusion of two selective agents namely, Chloramphenicol and Nystatin, to inhibit a wide range of both Gram-positive and Gram-negative bacterial species as well as yeasts and fungi. The inclusion of methylene blue as a redox indicator allows for the visualisation of any significant oxygen diffusion in the medium. Cultures may be examined microscopically after 48 hours incubation at 37°C for the presence of flagellate protozoans. If a negative result is obtained then the culture may be re-incubated for a further 72 hours. -
This is a medium that can be used to differentiate between some of the Enterobacteriacae on the basis of four reactions, fermentation of Lactose, Glucose and Sucrose and the production of H2S. For use the medium is inoculated using a pure culture of the test organism which should be smeared onto the surface of the slope and stabbed into the butt of the medium. For details of the many reactions that may arise during the use of this medium reference should be made to one of the many standard textbooks.
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This is a plate count agar originally suggested by the American Public Health Association for the estimation of total viable counts in food and dairy products.
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Tryptone Soya Broth (Modified) with Novobiocin (20mg/L) This is a selective enrichment broth for the isolation of Escherichia coli 0157, primarily from food and food products, and is capable of detecting the organisms even when they are present in small numbers. It is also increasingly being used in clinical laboratories when screening faecal samples. Based on Tryptone Soya Broth it is made selective for Escherichia coli 0157 by the addition of bile salts and Novobiocin and is also buffered to maintain the pH during incubation. This medium is generally used in conjunction with selective agar subculture (e.g. Sorbitol MacConkey Agar with Cefixime Tellurite – (CT-SMAC)). -
A general purpose broth suitable for the cultivation of most micro-organisms including many fastidious organisms and fungi. It is recommended by the United States Pharmacopoeia for sterility testing of many pharmaceutical products. -
Tryptone Water is an alternative medium to Peptone Water and more reliable for the testing of Indole production. The medium has a high content of Tryptophan that many organisms, particularly coliforms, break down to form Indole. After incubation add a few drops of Indole reagent to determine the Indole reaction (Red colour is Positive). -
Based on Christensen’s Medium this medium is generally used to detect rapid urease activity of Proteus spp although it can be used to detect urease activity of other Enterobacteriaceae. When used for the later purpose it is necessary to increase the incubation time to as long as 48 hours. -
A modification of Christensen’s Medium by Maslen this medium is generally used to detect rapid Urease activity of Proteus spp although it can be used to detect Urease activity of other Enterobacteriaceae including Urease producing Salmonella and Shigella. Unlike Christensen’s Medium when used for the later purpose it is not necessary to increase the incubation time.
