Mixed Culture Report

The following tests according to the lab manual were performed: gram stain, fermentation tubes, methyl red, vogues proskauer, sulfur, indole, motility and growing it up on MacConkey agar. The gram stain was performed incorrectly the first time. This is because the decolorizer was not on the bacterium slide for long enough, giving a false outcome.

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.

To perform this test, a tube of broth rich with glucose is acquired. In this tube is phenol red, a pH indicator. Initially, the tube appeared pink in color, indicating a normal pH level. Next, a sample of unknown #44 is introduced into this medium using the aseptic technique, and this is allowed to sit for several days. If the organism is able to ferment glucose, the pH in the medium would decrease and cause the phenol red to exhibit a yellow color. In addition to the straw color, gas can also be produced and trapped inside the Durham tube placed in the medium. This production of acid and gas is a direct result of the fermentation of glucose, as seen with unknown

In this experiment, an unknown bacterium was given to each individual student. The main purpose of this lab was to identify the given unknown bacteria going through a series of biochemical tests as one of the gram negative bacteria among six different Gram negative bacteria Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Salmonella typhimurium. At the very beginning, streaking method; T-streak technique was used to isolate the pure colonies. For the morphological identification of unknown bacteria, Gram Stain Method was done. Biochemical tests that were conducted for the experiment

The purpose of this lab was to identify an unknown microorganism using lab techniques. The importance of identifying microorganisms is essential to the survival of humans, expansion of modern day medicine and improvement of quality of life. In 1884, Hans Christian Gram designed a differential staining technique to identify bacteria that would change the future of microbiology. He give rise to a staining process, known as the Gram stain to differentiate microorganisms into two groups between positive and negative gram staining microorganisms. The Gram stain is essential in a lab technique as it distinguishes the cells based on the physical properties of the individual cell walls, and is almost always the first test preformed to differentiate a microorganism. The identification of weather a microorganism is gram positive or negative can revel the bacteria’s virulence, cell wall structure, resistance to antibiotics, resistance to physical disruptions and so much more. In order to identify the unknown provided, unknown #27, the Gram stain was the first test preformed. After discovering that the unknown bacterium was indefinitely a gram positive microorganism, the vast possibilities were narrowed down. However, In order to more definitively identify the unknown, the next step was to preform biochemical tests. A biochemical test identifies metabolic

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

During the final experiment for Microbiology will have to figure out the unknown organism given to us. The organisms will be narrowed down by using skills we have learned throughout the lab this quarter and the test results will narrow down to a single organism. The reason to perform experiments that determines the identity of bacterium is to find out how to treat it or what infections it is causing. In a controlled environment, students learned how to use various methods to determine how to differentiate between multiple bacteria. This lab report will be detailed steps explaining how to determine the identity of my unknown organism number 12.

The first steps to identifying the two unknown microorganisms in tube 33 & 34 is to perform a Gram Stain, prepare a MacConkey Agar plate, and subculture each unknown on to a Blood Heart Infusion Agar slant.

The purpose of this laboratory exercise was to perform tests necessary to be able to distinguish one microorganism from 10 others. Using a series of biochemical tests and characteristics, unknown #22 was concluded to be Pseudomonas aeruginosa. A dichotomous key was mapped out and used during this process. Using this provided guidance as well as organization as to what the result may be.

An unknown mixed culture was distributed by the Microbiology instructor labeled with a “3”, which was the assigned group number. The group was informed that there were two unknown microorganisms within the tube. Procedures were then completed in a specified order based on methods taught in the laboratory using the assistance of the assigned

Purpose: The purpose behind this unknown project is to help us determine the identity of the liquid culture we have selected. With the freedom we’ve been granted, we are permitted to use any of the tests that we have performed in our previous labs to assist us with identifying the organism. This project is intended to push us to use the knowledge we have acquired, using proper staining techniques and thorough understanding of testing techniques and results to draw conclusions.

In this experiment, each student was randomly assigned with a different species of gram- negative bacteria. The organism that I was assigned was Unknown #16. The identity of the gram-negative bacteria was determined to be Escherichia coli. The purpose of this report is to describe the various tests that helped develop a better understanding of the unknown microorganism in terms of the physiology, morphology, motility, and antimicrobic sensitivity it is characterized with. Indole production, hydrogen sulfide, and the colony morphology on the Eosin-methylene blue (EMB) plate, were the critical results that led to the conclusion that the organism was E. coli. In the indole production test, E. coli was one of two organisms,

When collecting nonsterile specimens such as urine, feces, and sputum on selective media, there are specific guidelines for not only the collection process but transportation and storage procedures as well, since the samples can begin to deteriorate at room temperature. A special swab and transport system ensures the specimen can be maintained in a stable condition for several hours. This transport system for the specimen, is a nonnutritive maintenance media which ensures the microbes can survive but not grow, a buffering system and an anaerobic environment that prevents the destruction of oxygen-sensitive bacteria. With nonsterile specimens containing a multitude of bacterial species, culturing them on selective media, will encourage the growth of only the suspected

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

Analyzing each plate, there was a physical feature that was easily identify for example the surface, texture color and elevation. In the lighted plate, each section had a smooth surface appearance, section 1 had a rigid texture but sections 2 and 3 had a buttery texture. Each section had a yellow color to it and its elevation was raised just enough to be noticed. The shaded plate had sections 1 and 3 with a smooth surface, buttery texture, yellow-whitish color and both raised in elevation. While as section 2 with a rough surface and rigid texture, a tan color and was completely flat in elevation. The plate with sterilizing water had no growing microbial in sections 1 or 2 but in section 3 there was one large microbial that was rough, fuzzy, yellow and convex. There is a clear difference between each agar plate with size, diversity, and