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weird bacteria - Update

JEDilworth bactitech at nospamhortonsbay.com
Mon Mar 10 11:38:08 EST 2003


It sounds like you're doing micro without a loop or wire to pick 
colonies or something to flame your loop in between touching colonies.

After you make your 6% agar (or use some differential media as I 
described in another posting) you need to streak for isolation. If you 
obtain two colony morphologies, each colony is a pure culture. You need 
to flame your loop, pick one colony and streak it to another plate. You 
then need to flame your loop again, pick the second colony type, plate 
to a separate plate and streak for isolation. Then flame again.

This is basic microbiology. If you're using bacteria, even in a genetics 
laboratory, I don't understand how you can do it without all of the 
basic equipment that you need. The ONLY way to separate bacteria is 
streak for isolation, using solid media. You put your inoculum down on 
about 1/3 of the plate. Then you turn the plate a little and streak out 
from this area. You then flame, and then streak another quadrant, then 
turn and streak the last quadrant. You then incubate the plate upside 
down, at least overnight, and look for different colony morphology.

A visit to your local clinical micro lab will help you immensely! We do 
this EVERY DAY. Gram negative rods don't look THAT different from each 
other upon staining, at least with Gram's stain. Some are smaller and 
thinner or thicker, but that doesn't help you separate them out.

Judy Dilworth, M.T. (ASCP)
Microbiology




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