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[Micro102]

Well my teacher gave us the task of finding the 2 types of bacteria in an unknown mixture. So far I have made a gram stain and a streak plate. In one week I will be checking up on them.

Does anyone have any experience on this and can provide some tips?

[Heron TSG]

Remember to check shape. (IE: Coccus, Bacillus, and Spirillum)

[Micro102]

I was looking more for the following

- What other tests should I do? She said she would take points off for doing a lot of them.

- How many times should I repeat streak plate method to get pure cultures?

[ChairmanPoo]

run the catalase test. That one is easy to do.

As for the streaks, for what I recall of my microbiology practices, we did them just once...  then again, I dont guarantee that it wasnt because of the monitors not willing to go over that more than once.
PD: This http://biology.about.com/c/ht/00/07/How_Streak_Bacterial_Culture0962932483.htm advices to do it thrice.
For what it's worth, what I recall is that we did the zigzag thing once, but covering half the plaque, and then two non-zigzag lines, after that

[Micro102]

Ok I have a more detailed description.

I have started with a gram stain, let's say they were gram positive Rods and gram negative Cocci, out of the following which would be the best test(s) to use?

-Agar slant
-Triple sugar iron agar
-H2S production
-Nitrate reduction
-Indole production
-Methyl red test
-Voges-Proskauer test
-Citrate utilization
-Urease activity
-Catalase activity
-Starch hydrolysis
-Lipid Hydrolysis
-Gelatin liquefaction
-Oxidase test

The only one I can rule out completely is the triple sugar iron. How do you tell which tests are better then the others?