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This blog was designed for the Biomedical Technology students at the Durban University of Technology, in Durban, South Africa. It consists of short notes on aspects that I feel that my students grapple with, and aims to provide a better explanation than that they would receive in lectures. It is also a very personal blog, where I feel comfortable 'talking' to my students.

Please email me sherlien@dut.ac.za




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Tuesday, March 16, 2010

reactions for coliforms (GNB)

UREA
pale peach to pink
Proteus is pos
Klebsiella pneumoniae is late pos
citrate
green to blue
Enterobacter aerogenes is pos
Salmonella typhimurium is pos
Proteus mirabilis is positive
phenylalanine deaminase
pale brown (like nutrient agar)
Proteus is pos (green colour after adding 10% FeCl2)
nutrient gelatin
remove after incubation and refridgerate for 20 min
Bacillus subtilis, Proteus is positive
indole
use SIM, add kovacs reagent
look for cherry red colour on top of medium
Escherichia coli, Enterobacter agglomerans, Klebsiella oxytoca are positive
motility
Klebsiella and Shigella are non motile
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2 comments:

  1. ZaneleMay 12, 2010

    Citrate test, can you please explain what cause the pH changes (the green to blue).

    Under Phanylalanine deaminase: what is the action of phanylalanine?, what does negative test look like?

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  2. sherlienMay 14, 2010

    the organism uses citrate. This results if the formation of byproducts which cause a change in the pH, which will cause a change in the colour of the pH indicator from green to blue.

    ReplyDelete

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