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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.

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Wednesday, March 17, 2010

A likely story......

the following relates to the orgs we have/are studying this semester.

Mr Brown is sick. He goes to the doctor who takes a specimen. Culture reveals an org that is citrate neg, urease neg, and does not produce hydrogen sulphide. It is a Gram negative bacillus.
What reaction would it give on Mac and CLED?
Why would it not grow on MSA?
If you inoculated a TSI and SIM, would it be incorrect to say that the org is non motile, indole pos and produces an alkaline slant? Why. (explain fully)
Name the organism.

2 comments:

  1. Mac- pink colonies, CLED- grows but i dnt knw. . if its a lactose fermenter

    it would not grow on MSA bcoz of the high NACL cooncentration

    yes. in TSI: acid slant, acid butt,
    in SIM; it is an indole positive with motility

    *p.s* answers are from the top of my head. . . plzz dont contaminate my cultures in the nxt prac if da answers are wrong. ..

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  2. miss conjunctivitusApril 11, 2010

    The org is E-coli in MAC-pink colonies LF,CLED-yellow colonies LF, they don't grow on MSA coz NaCl conc.is 7.5% this is to high for it to grow. Yes it is incorrect to say that because in TSI-there is an acid slant and in SIM it is indole + and is + for motility.

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