Microbiology Unknown 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.

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.

Often scientists work with bacteria that do not come in a labeled test tube— for example, bacterial samples taken from infected human tissue or from the soil—and the scientist must then identify the unknown microorganism in order to understand what behavior to expect from the organism, for example, a certain type of infection or antibiotic resistance. However, because of the relatively few forms of bacteria compared to animals and because of the lack of bacterial fossil records due to their asexually reproductive nature, the taxonomy used to classify animals cannot be applied to bacteria (Brown 275). In order to classify unknown bacteria, a variety of physiological and metabolic tests are available to narrow a sample down from the fathomless number of possibilities into a more manageable range. Once these tests have been performed, the researcher can consult Bergey’s Manual of Determinative Bacteriology, a systematically arranged and continually updated collection of all known bacteria based on their structure, metabolism, and other attributes.

My unknown organism #6 is Morganella morganii, which is a gram-negative bacillus rods commonly found in the environment and also in the intestinal tracts of humans, mammals, and reptiles as a normal flora. (3, 5) This bacterium Morganella morganii, was first discovered in the 1906 by a British bacteriologist named H. de R. Morgan. (2) Despite its wide distribution, it is an uncommon cause of community-acquired infection and is most often encountered inpostoperative and other nosocomial settings. (2, 3) Morganella morganii infections respond well to appropriate antibiotic therapy; however, its

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

|EMB Agar | |Distinguishes bacteria that ferment |Dark blue colonies with|E. coli and P. |

Many tests were completed on the unknown such as gram staining and inspection under microscopes to find whether the bacterium is gram positive or gram negative. Chemical resistance tests were also performed to see if certain chemicals affected the unknown growth or if it didn’t affect the bacteria at all. Each biochemical test

Citrobacter Freundii is a species of bacteria that can be potentially harmful to humans. It is known to cause meningitis by protruding into the brain and replicating itself (1). The Citrobacter species has also been found as a cause of some urinary tract infections, diarrhea, and even gastrointestinal diseases and symptoms (3). C. Freundii can be located in a wide variety of soils and water (3). Lastly, it is also the cause of many nosocomial infections due to its presence in water (1).

I used an inoculating needle to stab the SIM test tube and then incubated it at 37 degrees Celsius for 24 hours. The SIM test was used to test whether an organism has the ability to reduce sulfur to hydrogen sulfide. Iron salts in the media reacts with the hydrogen sulfide to form a black precipitate called ferric sulfide. If sulfur can be reduced than a black color will be seen in the tube. This test also sees if an organism is and indole producer. Indole producers are bacteria that produce the enzyme trytophanase which can hydrolyze tryptophan to pyruvate, ammonia and indole. To test for indole production,

The purpose of this study was to identify the unknown bacterium using biochemical tests and various methods that had been learned from previous the microbiology laboratory class. Identifying the unknown bacterium was determined by separating and differentiating possible

INTRODUCTION Unknown samples were distributed to students for the purpose of identifying the sample. Multiple biochemical tests, like phenylethyl alcohol agar and decarboxylase test, were conducted on the unknown sample. The goal of the biochemical tests was to practice using the techniques learned in the microbiology lab and gain experience performing the different tests. Further, the tests allowed for the identification of an unknown from the recorded results.

If the test was positive, then the colonies would start forming bubbles, and if it’s negative, then it won’t. Therefore, in our sample of the bacteria was a positive catalase reaction because we saw bubbles coming out after adding the hydrogen peroxide. Then, we used different agars whether there were selective or differential or even both to gives us more information about the unknown. One of the most imporatant agar that we used was Mannitol salt agar, which is both selective and differential medium.

At this point the presence of coliforms had been confirmed and the next step was to identify the type of coliform. This was done with the use of the IMViC test. The four sub tests within the IMViC are indole production, Methyl-red test, Voges-Proskaur test, and citrate utilization. The indole production test indicates whether or not the hydrolysis of trytophan into indole, pyruvate, and ammonia happened. The Methyl-red test indicated the Ph.

Introduction: Through the conduction of numerous experiments, the identity of two bacterial isolates was determined. The tested specimen was an unknown sample of a mixed culture of two different species of bacteria. The first step that was taken was obtaining a pure culture of each species of bacteria by isolating one species from the other. Once isolation was complete, the isolated cultures were tested using procedures that had been performed during previous lab sessions. A gram stain was performed on the two isolates. The isolate which had tested gram negative was then tested for the presence of cytochrome C and lactose fermentation. For the gram positive isolate, cell shape was determined and a catalase test was performed.