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    (Original post by badumdumtscht)
    heya

    so basically for one of my microbiology module experiments I have to isolate and identify 8 unknown bacteria. Our lecturer is giving us a list of 30 bacteria as to what they could be (*****).

    I've been amazing at micro so far, but I'm unsure how to go about this. I was thinking:
    -Streak for isolation using the general cocktail of 8 bacteria, incubate. May need to do several to properly get all 8 grown.
    -When each distinct colony has grown, take a sample from each and transfer inoculum to sterile broth cultures, incubate.
    -Transfer 0.25ml of each broth culture on to sterile plate/pouring plate, therefore giving 8 plates of pure culture. Incubate.
    -Do Gram stain, look at morphologies and google each of the 8, and narrow down the list for identification.

    So yeah I'm ok with the isolation part but surely there must be more things I can do than a Gram's stain for identification... ideas?
    I'm sure you have done other tests for classification of bacteria than just the Gram's stain, how about the acid fast test? I believe that one distinguishes between bacteria which have waxy cell walls and ones which don't. Have you thought about using the Endospores stain? This determines whether the bacterium produces tough spores.

    There are plenty more, it also doesn't hurt once in a while to try google
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    (Original post by badumdumtscht)
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    Hey There

    How long do you have to do this experiment and what year are you in? We did something like this in first year, but we only had about 10 possible species. Your plan sounds good, but you'll probably need to do multiple streak plates to get pure colonies (that may have been what you meant). But yes, isolate them, observe colony colour and morphology and do gram stains and motility tests. That should help identify some of them.

    Are you just looking at gram stains, motility and morphology? You will probably be able to identify some by the colour and appearance of the colonies (clusters/single cells/chains etc.) You might be lucky and get a few with distinctive colours, like Serratia Marcescens, which is bright red. Do you have access to antibiotics/antibiotic plates to test for resistance, if you do you'll have to do a bit of research to see which species are naturally resistant. You could do spore stains using Malachite green, if it's available. That might be useful for any Gram positive species(e.g. Bacillus).
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    I guess molecular biology is not an option?
 
 
 
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