How Gram Staining Is Negative Or Positive, It s...

Purpose: The purpose of this lab was to be able to gram stain given cultures and examine their reaction to certain dyes and determine whether the culture is negative or positive, it’s morphology, and arrangement of the cells. By using the Gram staining method, microorganisms can be narrowed down for the identification process as well as the leading to diagnosis Procedure: For this experiment, we were given three gram staining slides as well as a petri dish with five different types of incubated microorganisms that were divided. The five different organisms on the petri dish being observed were Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Klebsiella pneumonia, and yeast known as Candida albicans. On the surface of the†¦show more content†¦On the third slide, the smear was not taken from the petri dish, however it was taken from a thorough swab of the mouth and smeared within the given margins on the slide. The samples were then left to air dry. Once the slides dried, they were passed through a flame 4-5 times to follow the aseptic technique protocols. Once this was done, our next step was to begin the Gram staining process. First, is the Primary stain, using the crystal violet dye color. The slides were all laid out on top of a rack placed over the sink station and were flooded with the violet dye color; the slides were left with the dye on them for 1-2 minutes to assure they were stained. The slides were then rinsed off thoroughly. Next, the slides were stained with the Mordant (fixative) Iodine Gram stain which appears brown in color. The slides were then flooded with the brown dye for 1-2 minutes and then rinsed off. After all the slides were stained accordingly, they needed to be decolorized with 95% ethyl alcohol which is clear in color, and will be the determining factor between whether the stains are negative or positive. Just as we did with the crystal violet dye and the brown iodine dye, the slides were drowned with the 95% ethyl alcohol. The difference here was how long to leave the alcohol on each depending on how thick the samples were. The slides labeled â€Å"mouth† were removed within 20 seconds. The rest of the samples were removed within the following 10 seconds. Lastly, to complete