Identification of A Mixed Culture Unknown
An experiment such as this one serves the purpose of allowing us, the students, to apply what we already know about any organism and any laboratory procedure to the difficult task at hand. It is possible to identify a mixed culture by running familiar experiments on the unknown bacteria and taking information already known about specific bacteria and applying it to the results. This helps to slowly eliminate any bacteria that do not correspond with the results. I obtained tube number twelve to run various tests on. There are only two microorganisms, one is Gram positive and one is Gram negative, inside the test tube. The Gram positive possibilities are to be narrowed down from Bacillus cereus, Clostridium perfringens, Corynebacterium xerosis, Enterococcus faecalis, Streptococcus agalactaie, Staphylococcus aureus, and Staphylococcus epidermidis. The Gram negative possibilities are to be narrowed down from Enterobacter aerogenes, Escherichia coli, Moraxella catarrhalis, Neisseria flavescens, Psuedomonas aeruginosa, Proteus vulgaris, and Salmonella typhimurium.
I began my quest by conducting a Gram stain on my bacteria. I prepared a smear by placing a drop of water onto the center of a glass slide and then removed a loopful of bacteria from my tube to place within the water droplet. I used the aseptic technique while doing this making sure to flame the neck of the test tube and inoculating loop before and after transferring bacteria. Then, I waited a while in order to let the smear dry completely on the glass slide. Once it was dry, I placed my smear in my staining rack that I obtained from my lab drawer. I began the Gram stain by flooding the slide with crystal violet and waited for thirty seconds before I washed the slide with water for five seconds. Next, I flooded the slide with Gram's iodine and waited for sixty seconds before I again washed the slide with water for five seconds. Then, I decolorized my slide by...
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