The MR test media contains peptone, glucose, and a phosphate buffer (Stout et al, 45). To perform the MR test, I used the stabbing technique to inoculate the MR media. I sterilized the stabbing utensil under an open flame, obtained a small amount of unknown bacteria, and stabbed the MR media. Once the MR media was inoculated, I let it incubate for 24 hours in the 37°C hot room. After the 24-hour incubation, I added 15 drops of Methyl Red to the MR media to test for mixed acid production.
VP test (a.k.a. butanediol fermentation test) contains peptone, glucose, and a phosphate buffer in its media, which is the same media as the MR test (Stout et al, 47). To perform the VP test, I used the stabbing technique to inoculate the VP media. I sterilized the stabbing utensil under an open flame, obtained a small amount of unknown bacteria, and stabbed the VP media. Once the VP media was inoculated, I let it incubate for 24 hours in the 37°C hot room. After the 24-hour incubation, I added 15 drops of both Barrits Reagent A and Barrits Reagent B to the VP media, for a total of 30 drops.
The Citrate medium, a.k.a. Simmons Citrate Agar, contains sodium citrate as the sole carbon source and ammonium phosphate as the sole nitrogen source (Stout et al, 43). To perform the Citrate test, I used the stabbing technique to inoculate the Citrate media. I sterilized the stabbing utensil under an open flame, obtained a small amount of unknown bacteria, and stabbed the Citrate media. Once the Citrate media was inoculated, I let it incubate for 24 hours in the 37°C hot room. After the 24-hour incubation, I reviewed the Citrate media for a change in the PH of the media, which was indicated by a color change of blue or green.
The Urease test has a liqui...
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... result of the Gelatin test. The only test that did not match the E. aerogenes identification was the VP test. Possible errors made to not achieve an accurate test could be not waiting a full hour to view the color change or even not using the correct Reagent.
TSIA H2S Indole Motility MR VP Citrate Urease Gelatin
A/A +g (-) (-) (+) (-) *(-) (+) (-) (-)
It is important to know the identification of the E. aerogenes bacteria because it is pathogenic and it is known to cause infections.
References:
Leboffe, Michael J., and Burton E. Pierce. Microbiology: Laboratory Theory & Application.
Englewood, CO: Morton Pub., 2010. Print.
Madigan, Michael T. et al. Brock biology of Microorganisms. 13th ed. California: Benjamin Cummings, 2012. Print.
Stout, M.A, et al. "Microbiology Lab Notebook". Lab handbook. University of Texas. Arlington. 2014. Print.
I identified the genus and species of an unknown bacterial culture, #16, and I applied the following knowledge of morphologic, cultural and metabolic characteristics of the unknown microorganism according to the laboratory manual as well as my class notes and power point print outs. I was given an incubated agar slant labeled #16 and a rack of different tests to either examine or perform myself; the tests are as follows: Gram Stain; Nutrient Gelatin Test; Carbohydrate Fermentation; Dextrose, Lactose and Sucrose; IMVIC tests; Citrate, Indole, Mythel-Red and Vogues Proskauer test; as well as a Urease and TSI Test. Materials and Methods/Results Upon receiving the Microorganism (M.O.) #16, I prepared a slide by cleaning and drying it. Then, using a bottle of water I placed a sterile drop of water on the slide and used an inoculating loop, flame sterilized, I took a small sample of the unknown growth in my agar slant and smeared it onto the slide in a dime sized circle and then heat fixed it for ten minutes.
The first day an unknown sample was assigned to each group of students. The first test applied was a gram stain to test for gram positive or gram-negative bacteria. The morphology of the two types of bacteria was viewed under the microscope and recorded. Then the sample was put on agar plates using the quadrant streak method for isolation. There were three agar plates; one was incubated at room temperature, the second at 30 degrees Celsius, and the third at 37 degrees Celsius. By placing each plate at a different temperature optimal growth temperature can be predicted for both species of bacteria.
They can be found anywhere and identifying them becomes crucial to understanding their characteristics and their effects on other living things, especially humans. Biochemical testing helps us identify the microorganism present with great accuracy. The tests used in this experiment are rudimentary but are fundamental starting points for tests used in medical labs and helps students attain a better understanding of how tests are conducted in a real lab setting. The first step in this process is to use gram-staining technique to narrow down the unknown bacteria into one of the two big domains; gram-negative and gram-positive. Once the gram type is identified, biochemical tests are conducted to narrow down the specific bacterial species.
The purpose of this laboratory is to learn about cultural, morphological, and biochemical characteristics that are used in identifying bacterial isolates. Besides identifying the unknown culture, students also gain an understanding of the process of identification and the techniques and theory behind the process. Experiments such as gram stain, negative stain, endospore and other important tests in identifying unknown bacteria are performed. Various chemical tests were done and the results were carefully determined to identify the unknown bacteria. First session of lab started of by the selection of an unknown bacterium then inoculations of 2 tryptic soy gar (TSA) slants, 1 nutrient broth (TSB), 1 nutrient gelatin deep, 1 motility
Todar, K. (2002). Streptococcus pyogenes (Vol. 1). Madison: University of Wisconsin-Madison Department of Bact. Retrieved July 30, 2008, from http://www.textbookofbacteriology.net/streptococcus.html
Bacillus globigii. (n.d.) WordNet 3.0, Farlex clipart collection. (2003-2008). Retrieved March 20 2014 from http://www.thefreedictionary.com/Bacillus+globigii
Bacteria play a large role in our health, the environment, and most aspects of life. They can be used in beneficial ways, such as decomposing wastes, enhancing fertilizer for crops, and breaking down of substances that our bodies cannot. However, many bacteria can also be very harmful by causing disease. Understanding how to identify bacteria has numerous applications and is incredibly important for anyone planning to enter the medical field or begin a career in research. Having the background knowledge of identifying an unknown bacteria may one day aid healthcare professionals diagnose their patient with a particular bacterial infection or help researchers determine various clinical, agricultural, and numerous other uses for bacteria.
One test tube incubated for 120 hours at 98.6 degrees Fahrenheit containing the cultural (macroscopic) characteristics for bacterial cultures grown in nutrient broth revealed moderate growth accompanied by pungent odor, an opaque color, a flocculent surface and a turbid subsurface.
The methods used for this lab came from Leady, B. (2014) Fundamentals of Life Science Lab Manual. Toledo, Ohio: University of Toledo. No changes were made.
Streptococcus mutans is a gram positive cocci shaped bacteria. It is a facultative anaerobes. Streptococcus mutans is found in the oral cavity and now can be found in the heart tissue and valves. Considering the fact that Streptococcus mutans is a facultative anaerobe the bacteria is often found in between your teeth, around your gum line, and on your occlusal surfaces. Streptococcus mutans lives in temperatures that range from eighteen to forty degrees celsius falling into the mesophile category. Streptococcus mutans changes the environment by adhering to a bio-film layer produced on the enamel surface of your teeth from such things including: acidic foods that contain sugars and starch, drinks that contain carbonation and sugars, whiting products, tobacco use, and lack of oral home care. The first virulence factor is dependent on the synthesis of water-soluble glycans from the disaccharide sucrose. By breaking down the glycogen this allows help for bacteria adhere better. Next virulence factor, Streptococcus mutans has the ability to become more acid tolerant and cell to cell communication. Once the bacteria is colonized in the bio-film it starts to produce an acidic environment below a ph of 7.(Kreth, et al., 2008) By doing so, Streptococcus mutans out competes any other organism living on the teeth or in the oral cavity. This leads to the third factor, which displays a production of lactic acid fro...
...nvironmental Microbiology. New York: A John Wiley & Sons, Inc; 1992. pp. 125?156. Accessed December 2, 2013.
There were five test solutions used in this experiment, water being the control, which were mixed with a yeast solution to cause fermentation. A 1ml pipetman was used to measure 1 ml of each of the test solutions and placed them in separated test tubes. The 1 ml pipetman was then used to take 1ml of the yeast solution, and placed 1ml of yeast into the five test tubes all containing 1 ml of the test solutions. A 1ml graduated pipette was placed separately in each of the test tubes and extracted 1ml of the solutions into it. Once the mixture was in the pipette, someone from the group placed a piece of parafilm securely on the open end of the pipette and upon completion removed the top part of the graduated pipette.
A blood chemistry screen (test) provides vital information about your blood; it measures the levels of several substances in your blood. It most importantly provides your doctor with information about you general health, and helps identify certain problems with your body. The basic chemical elements in your blood are: Hydrogen, Oxygen, Iron, Calcium, Chloride, Potassium, and Sodium.
In this method, living spores which are resistant to whichever sterilizing agent is being tested are prepared in either a self contained system, such as dry sp...