micro question: serratia marcescens did not grow red on agar?

http://www.bioweb.uncc.edu/1110Lab/notes/notes1/la...

that plate looks like on plain nutrient agar.

Did you use good aseptic technique remember after flaming loop i would count up to 10 so that the loop has cooled down enough and not kill the bacteria if it was only one little colony you may have killed it already im supposing you did the easy 180 LOL. With the agar if incubated for a week you should have a large colony

If it was white and fluffy its just a contaminant of mold, or did you mean there is a clear zone, it shouldve been red if it was indeed S. marcenscens. Did you do only two plates? i remember doing unknowns and had to do 20 different agar plates, like 8 slants, and 4 broths. What are your other options because agar and emb dont tell much unless theres only 3-4 bacteria to test

Which bacteria give orange colonies on MacConkey's agar? It gives -ve citrate and indole, TSI: A/A.

red on macconkey agar??? perhaps it didn't have the gene for the fermentation pathway.....has the organism been genetically manipulated????

i am not really sure but i did this last time a long long time ago......mind if i ask....did you grow the organism in an anaerobic condition???i think you need this anaerobic chamber to enable the organism to utilise the anaerobic pathways......

use API20E for identification of the enteric gram negative organism if you are unsure

hope i am right