Unknown Paper

The purpose of this lab was to identify two unknown bacteria from a mixed culture. The reason for identification of unknown bacteria was to help students recognize different bacteria through different biochemical tests and characteristics. This is important in the medical field because identification of unknown bacteria can help treat a patient by knowing the contributing source of a disease. Also knowledge of different bacteria helped others make antibiotics used today. This lab was completed by using the methods learned thus far in identification of bacteria.

The purpose of this lab was to identify two unknown bacteria cultures using various differential tests. The identification of these unknown cultures was accomplished by separating and differentiating possible

An unknown bacterium was handed out by the lab instructor. The methods that have been learned so far in identifying bacteria were applied to this unknown. Procedures were followed as stated in the lab manual and biochemical test handouts. The first procedure that was done was a gram stain followed by a streak of the unknown on a TSA plate in order to determine the gram reaction and observe the colony morphology. After that, specific biochemical tests were performed for gram positive, since unknown number five was determined to be gram positive rod. The other tests were performed in this order: Mannitol Salt (MSA) streak, Blood Agar streak, Catalase test, Nitrate Reduction test, and Phenyl

The purpose of this lab was to identify two unknown bacteria cultures using various differential tests. The identification of these unknown cultures was accomplished by separating and differentiating possible bacteria based on specific biochemical characteristics. Whether the tests performed identified specific enzymatic reactions or metabolic pathways, each was used in a way to help recognize those specifics and identify the unknown cultures. The differential tests used to identify the unknown cultures were oxidase, catalase, lactose and sucrose fermentation, Kugler/iron agar, nitrate reduction, gelatin hydrolysis, starch hydrolysis, manitol salt, MR-VP, citrate, bile esculin,

The purpose of the Unknown Project is to help microbiology students learn to identify an unknown bacterium in a mixed culture by performing different types of tests in a lab. The student must be familiar with the tests and should be able to analyze and interpret the results. Based on the results attained, an organism may be proposed. But what is a mixed culture? A mixed culture contains either two or more different types of identified microorganisms in a container, like a test tube for example. The culture may carry either organisms from the same bacterial family or it may contain a mixture of fungi and bacteria or other combinations. Being able to identify different types of organisms is essential for us to know if by any case, risks are presented. These cultures are performed mainly in hospitals. They are obtained from different parts of a patient’s body, depending on the suspected infection. Registered Nurses can perform certain cultures like blood, urine, sputum, etc. and send them to the lab. A mixed culture has been helpful in previous medical research by helping determine whether a patient has a bacterial infection or not. For example, “Sputum samples often give mixed cultures. Since the patient coughs up the sputum from the lungs, the sample can become contaminated by normal mouth bacteria, resulting in multiple types of bacteria in the culture.” (http://www.ask.com/science/mixed-culture-microbiology-af200d033ce00db0) Many tests may be performed on this mixed

The second bacterium was gram positive. There are three tests that are used to identify gram positive bacteria. The three tests are hemolyses on blood agar, Mannitol fermentation on mannitol salt agar, and the coagulase test using plasma-containing serum in coagulase tubes.

The results that I observed by Gram Staining was Gram Negative rod (bacillus). Then, I performed a Negative Stain in order to further more validate that I had bacillus, since Negative Staining would provide an accurate determination of the shape of the microbe by staining the background of the microbe. In observation of my unknown using Negative Staining; I knew that I had a microbe with bacillus.

Problem: An unknown bacteria in test tube #13 needs to be identified out of the list of bacteria provided as possible. Hypothesis: If different tests were carried out to identify the bacteria’s characteristics, then the bacteria could be identified, because a dichotomous key can be used to eliminate all other bacteria in the list Procedure: 1. Obtain an inoculating loop, Bunsen burner, test tube #13 and a test tube rack. 2.

In addition, the purpose of this lab was to identify an unknown organism by performing a series of morphological and biochemical test. The three different types of test that were performed were the Gram stain test, Catalase test, and Red Blood Cell (RBCs) hemolytic test. Thus, the Gram stain test is used to classify bacteria by gram positive or negative and based on their cell

This experiment involves many qualitative tests to determine a mixed double unknown bacteria that contains two bacteria species; one gram-positive and one gram-negative. A dichotomous key was used in order to determine what tests needed to be conducted to define the particular bacteria. It is highly important for the tests to be followed as specified in the manual; otherwise, the bacteria could be falsely identified. Controls must be included in the testing to make sure there is something to compare the unknown results to. The tests conducted in this experiment included, gram stain, SIM, citrate, nitrate, oxidase, DNase, catalase, hemolysis, and novobiocin sensitivity. Through these tests one can conclude that the bacteria species present in the mixed unknown are Shigella

This project’s purpose as a whole was to receive an unknown bacteria and figure out what it is; One can figure this out by doing a series of tests. These tests include but are not limited to: gram stains, capsular stains, MacConkey agar plates, SIM, KIA, and UREA tubes, Catalase and Oxidase tests, Methyl Red and Voges-Proskauer test, and many, many more. Although that was just naming some of the tests one can do, what they are and how they’re done are further explained in the methods and reports section. Although there were many tests I was able to do, I was limited to an extent. I only had a few weeks to work on the project, and there were some unavailable tests I was unable to do.

The strategy used to determine the unknown organism was to first perform a gram stain to determine if the organism was either a gram negative or gram positive bacteria based on the color of cells. A TSA plate was inoculated to streak for isolation and purity. After colonies were incubated characteristics of colony morphology were recorded and a TSB broth and TSA slant were inoculated to determine characteristics of growth in broth and slant. Another TSA plate was inoculated to determine growth under anaerobic conditions. The next step was to look over the class results for biochemical test and create a dichotomous key to determine which test were useful and which were unnecessary to perform. The gram stain helped determine that the organism

The gram stain result showed that my unknown was a pink long individual rods this means that it is a gram negative bacilli. The growth on the agar of unknown appear off-white with straight growth and the broth growth was uniform fine turbidity. Uniform fine turbidity means there is cloudy growth throughout the test tube. As time progressed the broth appeared clear with some sediment. This could suggest that the bacterium is a slow grower or that the cells are older and dying. This can affect the results of testing. We did to place an agar slant and broth tube in the incubator for 48 hours at 25 degrees Celsius to see if the temperature affects the growth. The agar slant looked the same as agar slant that was grown at 37 degrees Celsius. The broth that was incubated for 48 hours at 25 degrees Celsius did suggest that it was able to grow better at this temperature being the growth in tube with the thick white clunks floating throughout and the uniform fine turbidity.

Under the microscope a rod shape pink cell was shown representing gram negative. This gram stain helps to determine the next test that would take place for further identification of the unknown organisms. The grain stain technique determined that unknown four was gram negative so the catalase test was further used where a small sample of the bacterium was added to a slide and a small drop of hydrogen peroxide was added directly to the unknown bacterium where no bubble formed. Further testing was also administered to unknown four such as citrate, urease, gelatinase and motility. With the citrate test a small sample taken from the agar plate is added to the medium. The urease test a sample was taken from the agar plate and added to the urea slant, and finally the gelatinase use the sterilize loop to take up a sample of the bacterium which was added immediately to the gelatinase medium. In unknown four motility test a sterile needle is stab 2/3 of the way to the bottom of the motility medium.

An organism of unknown origin was selected by the course instructor in an effort to properly identify the organism with the utilization of a series of biochemical tests. This exercise was of extreme importance during the termination of the course because it was essential that each student be able to apply the practical knowledge learned through class lectures, and lab practicals in an effort to individualize such experience so that each student could properly handle a bacterial culture and identify its origin. In essence, the task of identifying the selected organism via various test is essential in order to determine key features of such organism. The test results ultimately disclose how the organism functions, and this information is useful for proper identification and handling of such culture.