Gram Reaction Lab Report

An unknown bacterium was handed out by Dr. Honer. The appropriate tests were prepared and applied. The first procedure that was done was the gram stain. Under a microscope, if the gram stain is purple, the bacterium is gram positive, if the stain is red, it is gram negative. The next test was the fermentation tests for glucose, sucrose and

The purpose of this lab was to identify an unknown bacteria culture using differential tests. The identification of the unknown culture was accomplished by identifying the bacteria based on its specific metabolic characteristics and morphology. It is suggested that culture 11 is a sample of Enterobacter aerogenes.

Next I performed a KOH test to further confirm that my organism was a Gram-negative species. For the KOH test, I added 3 drops of 10% potassium hydroxide (KOH) to a small drop of distilled water onto a clean microscope slide, transferred a visible clump of organism to the KOH solution using my inoculating loop. I than mixed the cells into the solution using small, circular motions for 60 seconds and then lifted up the loop to look for what appears to be a “stringing” affect which means it’s confirmed that it is gram- negative species. Next, I created a streak plate using nutrient agar so that I could see pure culture of my organism. I aseptically obtained a loop full of my organism and gently inoculated one quarter of the nutrient agar plate by running the loop back and forth across the surface. I then flame sterilized the inoculating loop, allowing it to cool for 10 seconds, and then streaked the organism from quadrant I into quadrant II using a zigzag motion technique. I repeated those steps streaking from quadrant II to quadrant III and then streaking from quadrant III to quadrant IV. Once completed, I put the streak plate in the incubator at 37° for 24-48 hours. 48 hours later, I check my streak plate and it had a lot of growth on it. I was able to determine that the organism was definitely an off white color, opaque. The IV quadrant was the quadrant that best

This experiment was conducted to find the genus and species of an unknown bacteria prescribed by the lab teacher, which was unknown bacteria GA3 in my case. Identification of unknown bacteria techniques are used on an every day basis to figure out what type of bacteria it is and to find the best method of how to treat a patient with this bacteria (1). All five “I’s” of Microbiology were used in the testing for the unknown culture. Inoculation was used several times to put the unknown culture into agar plates or into biochemical test tubes. After Inoculation of these tubes or plates, they always were placed into the incubator for further growth and development. Isolation was used to make sure we got the correct bacteria we were testing for. After each further isolation, we gram stained the culture and inspected the culture under a microscope to further help in the identification process of the unknown bacteria. Multiple tests were done on the unknown culture to make sure we were confident in what kind of bacteria the unknown was.

In the world of microbiology it is vitally important to be able to discern the identities of microorganisms. Not only is it important in a lab setting but as well as in healthcare in general. Properly identify what strain of bacteria a person has will aid in the proper medicine and dose given. Throughout the semester we have learned about different types of bacteria and certain test that can clearly identify them. The purpose of this lab report is to identify a Gram-positive or Gram-negative bacterium. Using all the knowledge of procedures and lab techniques identify the unknown and discuss all the tests you performed.

A wide variety of processes had been performed to determine what culture had been acquired in class. My group had acquired culture tube unknown #3. We first isolated the bacteria. In this step we took the broth of the unknown #3 and grew it on an agar plate. The first process that had been performed was discontinuous streaking, and continuous streaking to grow the culture for future use in the lab and to have extra to perform a whole variety of test to determine the unknown. The next experiment that had been performed

In class, we were given the task of identifying an unknown bacterium broth culture. After receiving number 69, I went through several tests to figure out what bacterium I received. First, I created a slide from my broth by putting a small amount of the unknown broth on to a clean slide and letting it dry for ten minutes. After this, I stained the slide by applying four reagents in order; crystal violet, grams iodine, decolorizer and safranin. From the stained slide, I discovered that this bacterium was gram-negative, which would determine the next couple of tests I would do to identify my unknown bacterium. I began by streaking for confluent growth from my broth culture onto a TSA plate. From the TSA plate, I aseptically transferred a loop

I have completed the testing on the organism you provided to me that was obtained from one of your patients, patient #17. Upon culturing the specimen and conducting the gram staining procedure, I was able to determine the microorganism is a Gram-negative rod shaped organism. The culture plate showed no evidence of hemolysis. Once I determined its bacterial classification, I then proceeded to order additional laboratory tests specifically used for Gram-negative organisms. The tests included:

The first step in identifying my organism was to put it on a slide, stain it, and look at it under the microscope. I used the gram stain to figure out whether my organism was gram-positive or gram-negative. When I looked into the microscope it was all pink so I determined that it was gram-negative. The organism was bacillus in shape and was single and diplo. Then I determined that I had to focus on tests specific to gram-negative organisms. The tests I chose to perform were: OF glucose test, Citrate test, H2S test, Indole test, Motility test, and Urease test. The OF glucose test concluded that the organism was a fermenter. The citrate, H2S, and Urease tests were all positive. The Indole test was negative. The organism is motile. The unknown organism is Proteus mirabilis.

1. Describe what the results were. According to the results, the higher the concentration of sodium thiosulphate the higher the reaction rate. The graph above shows the reaction rate compared to the sodium thiosulphate solution is almost a straight line showing the relationship of the sodium thiosulphate and the rate of reaction.

This lab and its procedures are all about finding out the unknown identification of a given bacteria. The lab consists of specific techniques, tests, chemicals, and vocabulary that are necessary for the finding of the bacterial identity. A bacterium is randomly assigned and it is a group effort to find the bacteria name through many of its specialties and characteristics. An example of classifying it would be to determine whether the bacteria is catalase negative or positive, or if the species is gram negative or positive. This lab is of huge significance because of its medical microbiology connections. Scientists Gurtler and Stanisich explained the connections more eloquently. They stated, in their medical article, that, “Medical microbiology

On the first day of testing, a gram stain test, a KOH test, a catalase test, and an oxidase test were completed. The gram stain test indicated that the unknown species is a gram positive rod, and the bacteria showed no strings during the KOH test confirming that the species is gram positive. From these two tests, the unknown was concluded to be in the family Bacillicae. The bacteria remained yellow on the cotton swab even after the oxidase reagent was dropped onto the swab showing that the bacteria is oxidase negative. For the second day of testing, the bacteria were inoculated on an SBA plate, and the analysis of this plate was difficult. The result of the SBA plate was difficult to discern, and it was unclear if the bacteria completed beta hemolysis or alpha hemolysis. Therefore, an additional SBA test needed to be completed, and with this second test it was more obvious that the SBA plate underwent alpha hemolysis. The SBA result showing negative beta hemolysis, along with the negative result from the oxidase test, indicated that Bacillus cereus was not the identity of the unknown. At the same time that the SBA hemolysis test was undergone, the inoculation of an MSA plate at 37 degrees for 24 hours was also completed. There was yellow growth on the MSA plate indicating that it could grow at 7.5% NaCl and ferment mannitol.

This report represents my individual effort. I did not receive or offer aid to anyone when performing this assignment, nor did I plagiarize any material.

At Q 1 A reaction is at equilibrium when the ratio of the product and the reactant side are equal. This could further be seen by the reaction quotient depicted by Qc is equal to the equilibrium constant, Kc, of the given chemical reaction. Given that aA + bB ↔ cC +dD, the small letters being the mole coefficients and the big letters being the molecules of the chemical equation, K_eq=([〖C]〗^c [〖D]〗^d)/([〖A]〗^a [〖B]〗^b ) is the formula for finding the Kc of any given reversible equation. The symbol used in writing an equation that involves equilibrium is a double-headed arrow to indicate that indeed, the reaction could go forward and backward.

For the purpose of the gram staining experiment was to learn this specific type of staining technique, as well as learn how distinguish the differences between Gram positive and Gram negative stains. This technique uses crystal violet stain, Gram’s Iodine, Ethyl Alcohol, and Safranin. These dyes are used in order to distinguish between the different types of cells. For example, Gram positive staining will result in a purple color, and Gram negative staining will result in a red or pinkish color (University of Central Oklahoma department of biology, 2016). When a bacteria results in a purple stain it is categorized as a gram-positive stain because the alcohol that was used to decolorize the bacteria was not successful. Its’ cell wall is made with a thick layer of peptidoglycan and holds the crystal violet color (Case, Funke, & Tortora). When a bacteria results in a red or pinkish color, this means that it loses the crystal violet dye color after being decolorized and keeps the Safranin dye. It would then become categorized as a gram-negative stain (Case, Funke, & Tortora). A gram-negative bacteria has a cell wall made of a thin layer of peptidoglycan and a thick layer of lipopolysaccharides thus holding onto the red dye (Case, Funke, & Tortora). Bacteria have different shapes and these shapes determine what family they belong in. There are