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Unknown Bacteria Report

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When given an unknown bacteria there are a multitude of steps one must go through to be able to correctly identify what bacteria was given. It is important to correctly identify the bacteria because some bacteria are more harmful than others. The gram stain is the first test that should be performed because it helps narrow down the possibilities by telling one whether the bacteria is gram positive or gram negative. After this test is performed, one shall place bacteria on/in Mannitol Salt agar, MacConkey agar, Eosin Methylene Blue agar, Urea agar, Simmon’s Citrate, Purple Beef broth with Lactose and finally Purple Beef broth with Sucrose. A streak plate should also be made up, this helps one identify the morphology of the colonies. Once the streak plate has been inoculated, and colonies have grown, the Catalase test would then be performed. After receiving the results from all the tests listed above, it has been concluded that Escherichia Coli was the unknown bacteria. The first and most important test that should be performed on the bacteria is the Gram Stain. This test is a process of using multiple stains to differentiate between Gram Negative and Gram Positive organisms (Microbugz). If a bacterium is Gram Positive the cells will appear purple …show more content…

It is differential for PH levels and selective for salt. If a bacterium holds a PH level below 6.8 the agar will turn yellow, which was formerly pink when sterile. With a PH level between 7.4 and 8.4 the agar will turn red. If the PH level is above 8.4 the bacteria cannot ferment mannitol, which would mean the agar has no change and stays pink. This medium is selective for salt so if a bacterium is not halotolerant, it cannot grow because of the high salt concentration in the Mannitol Salt agar (Microbugz). The unknown bacterium that was tested was negative for growth and fermentation, with that being said, the agar had no color change and stayed

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532 Words | 3 Pages

Methods Unknown microbial #398 went through several of tests in order to identify its characteristics when isolated from a urine sample of Doris, a 64- year old patient with a kidney infection. To identify unknown #398, must prepare a working and a reserve stock by the inoculation from a broth culture and by quadrant streaking method on a PEM and EMP plates. The following test procedures were incubated at 37°C for 48 hours for observation and identification for unknown #398. The identification of unknown #398 followed test procedures from Brown1.

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636 Words | 3 Pages

We got negative for indole (no production of indole, pyruvic acid and ammonia), negative for Methyl Red (our bacteria does not perform mixed-acid fermentation when supplied glucose), negative for Voges-Proskauer (no fermentation of glucose in order to produce 2,3-Butanediol-Butanediol fermentation), but positive for Citrate utilization, which means our bacteria uses citrate as a sole carbon source and energy. Something interesting here is that according to the lab textbook organism that degrade citrate must also use ammonium salts, and in the process, they produce ammonia that causes the medium to become alkaline (under this condition the medium turns to deep Prussian blue, indicating the utilization of citrate). The genus Alcaligenes is well known for being alkali-producing

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449 Words | 2 Pages

Since unknown organism B was gram positive, I had decided my first biochemical test would be the Catalase test per lab manual. The result of the catalase test after adding H2O2 was immediate air bubbles. The second biochemical test performed on organism B was starch agar per lab manual. Once the reagent was added I did not

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1200 Words | 5 Pages

Neutral red acts as a pH indicator, it remains colorless when the pH is above 6.8 and becomes red when the pH falls lower than 6.8 (3). The gram-negative coliform type bacteria would turn this medium red, while bacteria that do not ferment lactose will not incur a color change. The MSA plate is also considered a selective and differential medium. MacConkey is commonly used to differentiate between different species in the Enterobacteriaceae family. MSA is considered selective because it contains 7.5% NaCl and only bacteria that can survive the high osmotic pressure due to the sodium chloride will be able to grow on this plate.

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408 Words | 2 Pages

The unknown bacteria was then tested on multiple selective and differential media. Growth was present on the MacConkey Agar and the colonies were the same color as the plate, which told me my bacteria was gram negative and did not ferment lactose. There was no growth on the Mannitol Salt Agar, and this told me the unknown was not salt tolerant and did not

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1444 Words | 6 Pages

The tube was placed back in incubation for 96 more hours to observe any more positives. 2.10 Catalase Test A trypticase soy agar plate was used and after incubation, four drops of 3% Hydrogen Peroxide was added to the plate to flow over the bacterial growth. A presence of bubbling was observed. 2.11 Starch Hydrolysis

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771 Words | 4 Pages

My bacterium turned out to be gram positive. When conducting these tests, I only had to do the coagulase test and the catalase test because when doing the catalase test, the reaction was that it had bubbled. If it did not bubble, or have a positive reaction, then I would not have had to do the coagulase test. Also, since my bacterium caused a positive catalase test, I only had to do the coagulase test and no other tests. This is because with staphylococcus organisms, these are the only tests

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1556 Words | 7 Pages

The presence of nitrate reductase also came back positive, this implies that the microbe is capable of reducing nitrate to nitrite. The catalase displays that the bacteria is able to break down the toxic forms of oxygen as well. However, the Oxidase test indicates that the microbe is unable to produce cytochrome c oxidase. The MR-VP test shows that the bacteria can carry out mixed acid fermentation when supplied with glucose but is incapable of 2,3 butanediol fermentation after the following mixed-acid fermentation. The tryptophanase test indicates that the bacteria is unable to synthesize tryptophanase in order to produce indole.

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624 Words | 3 Pages

Aseptic technique was initiated at the beginning of this experiment by cleaning the work surface with disinfected wipes. Personal protectives equipment was also worn. The material utilized in this experiment was: S. epidermidis culture broth, sterile cotton swab, streak plate, forceps in 70% alcohol, a lit tea light, and the three antibiotic disks (novobiocin, gentamicin, penicillin). The first step, I divided a plate into three quadrants and labelled them with the different antibiotic names. Using the lit tea light, like a bursen burner, I flamed the mouth of the S. epidermidis culture.

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517 Words | 3 Pages

Catalase activity test establishes whether the bacterium produces the enzyme catalase. The eosin methylene blue test or EMB, inhibits the growth of gram positive bacteria and tests whether or not gram negative bacteria can ferment lactose. Lactose fermentation testing is done to see if the bacterium is capable of fermenting sugar by testing for acid and gas production. These are the possible tests that are needed in order to identify unknown

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452 Words | 2 Pages

After experiment on microscope under oil immersion, I learned that my Unknown is gram positive. Under the lens, the bacteria appears in purple color. Its morphology is cocci arranged in cluster. However, during decolorizing process, I put too much alcohol to the crystal violet-iodine complex making the color overly removed. That led to the result of my gram positive has slightly redish

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1184 Words | 5 Pages

Testing for the Presence of Macromolecules in McDonald’s Happy Meals Clayton Wagoner MST Biology White 4 duPont Manual High School Introduction Carbohydrates, lipids, proteins, and nucleic acids are organic molecules found in every living organism. These macromolecules are large carbon based structures. The macromolecules are assembled by joining several smaller units, called monomers, together through a chemical reaction called dehydration synthesis. The resulting polymer can be disassembled through the complementary process called hydrolysis.

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1057 Words | 5 Pages

The Another medium used was MAC, it is used to isolate and differentiate gram-negative organisms and it is a pink, dusty rose color. Lastly, the Citrate Slant is a green color and it was used as a differential test to examine enzymes. The media were inoculated at 37°C for 48 hours, then it was observed to determine the

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1614 Words | 7 Pages

Salmonella suspect colonies grow as red colonies with a black center in Xylose Lysine Deoxycholate (XLD) agar. Red slant (alkaline) and yellow butt (acid) with H2S production is another characteristic of Salmonella in Triple Sugar Iron (TSI) agar (Quinn et. al., 1994). On the other hand, serology or serotyping is based on the characterization of the somatic (O), flagellar (H), and envelope (V)

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1772 Words | 8 Pages

This can be tested by simply mixing the serum of suspected individual which contain the antibodies with the antigens of specific bacteria the accumulation of clumps confirms the presence of particular bacterial infection.[2] This test can be performed in various ways including slide agglutination reaction, tube agglutination reaction, indirect agglutination inhibition reactions etc. Another important practical application involves blood group test of

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