A Report On Gram + Cocci Essay

1162 Words Dec 4th, 2015 null Page
Gram + Cocci To identify the Gram + cocci I first performed a catalyst test which produced oxygen bubbles and indicated a positive catalase result. The next test I preformed was a mannitol salt test using a mannitol-salt agar plate and the results showed positive fermentation turning the plate yellow and also positive growth. This led me to conclusion that my unknown Gram + cocci was Staphylococcus aureus.
Gram – Rod To identify the unknown Gram – rod I first performed a H2S production test using a peptone-iron agar deep. The results of the H2S production test showed no production of H2S near the inoculation point which meant that my next test performed would be the MR/VP test using MR/VP broth. The MR test showed positive results indicated by the red color of the broth and the VP test showed negative results which were indicated by the lack of red color when adding the dye. The results of the MR/VP test lead me to the conclusion that my unknown was Escherichia coli but to be absolutely sure that the unknown was in fact E.coli I performed a T-streak on an EMB plate. The colonies that had grown on the EMB had a metallic green sheen to them which is a characteristic of E.coli. I was able to successfully identify my unknown Gram – rod as Escherichia coli.

Gram + Rod The first test I performed in identifying my unknown Gram + rod was a catalase test. The catalase test showed small oxygen bubble production which was interpreted as a positive result. Since I had a positive…

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