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positive or negative mannitol salt agar plate??!! - (Apr/28/2011 )

above is what the mannitol salt agar plate for an unknown I must figure out.

That's where you all come in; Is this a POSITIVE (colonies surrounded by YELLOW zones) or NEGATIVE (colonies surrounded by PINK/RED zones)????????

For those of you unfamiliar with the test, the original agar's color was light red/dark pink.
Given the fact that half is yellow and half is pinkish, I belive that is can still be considered a positive reaction (yellow zones) since some yellow actually appeared. It seems like we streaked it too much, but you guys be the judge...

(ps. i kinda want it to be negative (pink) bc the unknown i believe it is has a negative result)



Are you sure you had a pure culture? Maybe you had a contaminant?

-lab rat-

the sample was taken from a TSA slant from the unknown. The slant did not look contaminated and was in room temp for about 4 days after I innoculated the MSA plate (which was incubated at 37 degrees Celcius) I'm at a lost though with identifying this unknown ;(


I would do the test again maybe with a little less streaking.