Determining an Unknown Through Deferential Stains and Biochemical Tests Introduction There are many reasons for knowing the identity of microorganisms. The reasons range from knowing the causative agent of a disease in a patient, so as to know how it can be treated, to knowing the correct microorganism to be used for making certain foods or antibiotics. This study was done by applying all of the methods that have been learned so far in the microbiology laboratory class for the identification of unknown bacteria. The identification process can be completed with a series of deferential stains and biochemical tests. Creating a dichotomous key helps to limit the amount of biochemical tests done on an unknown organism and by observation …show more content…
The enzyme urease breaks urea down into NH3 and CO2. An orange broth containing urea is used for this test and needs to be inoculated with the gram negative bacteria. A pink color in the medium indicates a urease-positive organism, an orange or yellow is negative. The IMViC test is a series of different tests that differentiate between enterics. One is the Indole test. This test tells whether the bacterium possesses tryptophanase which is the enzyme that breaks down tryptophan into indole. The agar contains tryptic soy broth so if the bacterium contains tryptophanase, indole is produced. This production of indole is seen by adding Kovac’s reagent which causes a red ring to be seen at the top of the tube. The citrate test is also used to see which kind of products the bacteria make. It uses a green agar slant that contains sodium and ammonium phosphate. Bromythymol blue dye is late added as an indicator. Inoculation of the slant with a needle using a zig-zag then stab technique was used with the gram positive bacterium. Conversion of the medium to blue is a positive citrate result. All plates, slants, and broths were incubated at 37°C for 24‐48 hours. Results Test Unknown 16 Unknown 16 Gram Stain + - Color Yellow Yellow Shape Rod Rod Lactose n/a + Indole n/a - Urease n/a + Citrate + + Key: (+) = Positive Test (-) = Negative Test N/A = Not Used for Determination Discussion The gram
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 identification of unknown organisms carries important ramifications that can be applied to many real world scenarios. In keeping with quality assurance beverages, food, cosmetics, and other products are frequently inspected for contaminants resulting from a presence of pathogenic bacteria. In medicine, a physician’s diagnosis and consequent treatment is largely determined from samples collected from infection sites that have been analyzed using microbial tests.
The main idea of this experiment was to correctly identify the unknown bacteria, #3. Identification of unknown bacteria yields multiple benefits in many different areas in the research of microorganisms. In this experiment I performed many different test dealing with things such as the presence of enzymes, fermentation abilities and different chemical reactions. Observations made from the tests were then compared to a gram negative unknown chart in order to identify the bacteria. Based off of my results and the chart, I concluded the bacteria #3 was the bacteria Escherichia coli. E. coli is most commonly found in the intestines of warm blooded organisms. Most E. coli strands are non pathogenic however, there are strands
The purpose of the bacterial unknown independent study experiment completed throughout the course of this lab was to determine the identity of an unknown bacterial species. The unknown bacteria sample was chosen from numerous samples provided by the instructor. The starting unknown sample, unknown #15 was a mixed bacterial culture and a broad approach taken to identify the sample. Various biochemical tests were completed to identify the bacterial species along with the use of databases such as Gideon and Bergey’s to compare the test results of known bacteria to the results of the unknown sample. Information was gathered from the other sources and databases and phenotypic testing completed and the results compared to the database results. Aseptic
Unknown lab report# 24 Introduction Microbiology is a study of organisms that surrounds us every day. It requires an educational understanding to identify organisms, and the ability to distinguish different bacteria’s. In applying the learning process of the different bacteria’s, unknown bacteria samples are given to be studied and identified.
There are many reasons for knowing the identity of microorganisms. The reasons range from knowing the causative agent of a disease in a patient, so as to know how it can be treated, to knowing the correct microorganism to be used for making certain foods or antibiotics. This study was done by applying all of the methods that I have been learned so far in the microbiology laboratory class for the identification of an unknown bacterium.
morganii, P. mirabilis, P. myxofaciens, P. penneri, P. vulgaris, and P. rettgeri. Urease test has a pH indicator in it, phenol red, which will turn the medium pink or red versus the yellow or yellow orange color of the medium originally. The pH rises because of the end products, specifically ammonia, making the pH rise. The ammonia is made from urease breaking down nitrogen and carbon bonds. From this I once again used citrate to eliminate four more species, E. psidii, P. heimbachae, P. Rustigianii, and T. ptyseos.
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.
Different microbes can transmit and produce different types of diseases and infections. Having an unknown bacterium in the body can be a life and death situation. It is very important especially in the healthcare industry that providers are able to differentiate between organisms that are pathogenic and administer the appropriate treatment to their patients. Applying methods that were previously studied in lab, students must be able to isolate an unknown specimen by using laboratory techniques and biochemical tests.
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.
|EMB Agar | |Distinguishes bacteria that ferment |Dark blue colonies with|E. coli and P. |
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
In category IV, agar plates were used containing differential and selective aspects to determine the unknown bacterium. The first media test was the EMB. EMB separates fecal coliforms that are produced through carbohydrates that are fermentable, such as sucrose and lactose. The different fecal coliforms represent the differential factor of this test, while the selective factor selects against gram positive organisms. Lactose fermenters appear purple, pink, blue, and black colonies, while non-lactose fermenters appear clear to light orange. This occurs because Eosin Y and methylene indicators react at low pH forming the purple precipitate. On the other hand, vigorous fermenters appear metallic green indicate either coliform production or lactose
Correct identification of a microorganism allows for proper investigation of a particular species, and prevention or treatment of a disease if necessary. During lab, students were instructed to choose a test tube inoculated with an unknown organism and then prompted to initiate a series of appropriate lab tests to correctly identify the organism.
Another purpose of this experiment is to stress the importance of knowing the identity of a microorganism. Knowing the species of microorganism present in a sample provides a