In order to identify which Gram negative bacteria was present, Klebsiella pneumonia or Enterobacter aerogenes, it was decided to perform Urea test, that finally confirmed that gram negative unknown was Enterobacter aerogenes. The production of gas by the fermentation was monitored using the inverted Durham tubes. By going through the steps to identify the microorganism, students began to comprehend infectious disease. So, the pre-constructed sequence of tests was still performed as if all five of the Gram positive options were still possible. One test tube has been provided with a mixture a Gram p ositive and a Gram negativ e bacteria. After incubation and adding the methyl red drops to the results, the test tube turned red in color; a positive test for methyl red. Upon observation the isolation plate showed growth of two different colonies.
The Voges-Proskauer test to detect organisms that are able to ferment glucose, but convert the products to acetoin and 2,3-butanediol. After 2 days the green simmon citrate turns to blue. . Then the mixture was soaked in Iodine for 1 min. Gram positive, on the other hand, leads to contradicting results. Name: Danielle Title: Unknown Lab Report Introduction: There are many reasons for identifying an unknown bacterium.
What does the blood agar select for? A Mannitol agar plate was obtained and inoculated with the bacterium. The purpose of this test is to determine whether or not a bacterium is able to utilize citrate as its sole carbon source McDonald et al. These antibiotics help facilitate quicker healing times for such things as burns, scraps, and certain skin infections Swartzburg, 2009. Everyone is susceptible to S. This was possible because Mannitol Salt Agar is a selective medium along with differential that only allows for the growth of specific Gram positive bacteria due to its high salt content McDonald et al.
In this test, the result showed a clearing around the streak of bacteria indicating that it was a positive result. When this happens, the top of the test tube will turn a reddish pink color. The purpose for this study is for the microorganism to be identified. This test is used to detect the presence of catalase, which helps to breakdown toxic hydrogen peroxide produced from the transport of high-energy electrons directly to oxygen. Floyd, Jeanetta and Kennedy, Emily. However, a problem was faced after the isolation was incubated.
After observation, a sample was taken from the isolated colony on the streak plate and another streak plate was done with that, trying to further isolate the colonies. This was the only test necessary to determine the unknown gram negative bacteria in unknown stock 123. Unknown Lab Report Microbiology Unknown A Sonia Kabra November 26, 2014 Introduction There are numerous reasons for identifying unknown bacteria. Alt 5 was given as a substitute for a gram-negative bacterium, due to no growth in original test tube 122. The strain O157:H7 releases a toxin into the body cavities that initiates an illness in mammals 2.
Reagent A is a solution of -naphthol and alcohol. Once the two bacteria were incubated, grown, and isolated they were each individually streaked on a Trypticase Soy Agar plate to isolate individual colonies to be studied, tested and identified. Lab Manual for General Mircobiology. It is also important for students to understand sterile techniques, diagnostic steps, treatment, risk assessment, transmission, and prevention of microorganisms. Flowchart 2 is also available for the results of this unknown.
Knowing the differences in bacterial structure and response is essential for all future and current healthcare providers. Numerous studies clearly show that a large number of hospital strains have the ability to form multilayered. Table 1: Tests and Results for Gram Negative Bacteria Test Purpose Reagents or Media Observations Results Gram Stain To determine whether the bacteria was gram negative or gram positive Crystal violet, Iodine, Alcohol, Safranin Red Rods Gram Negative bacteria Casein To determine if the enzyme casease was produced to break down the milk enzyme casein Milk Agar white opaque Milk Agar changed color where bacteria was smeared, turning a brown color Positive, the bacteria produced casease The first test performed on the gram positive bacteria was the Nitrate Test which turned red after adding reagents giving a positive result meaning the bacteria reduced nitrate into nitrite or something further. Try to avoid unpasteurized dairy products. A negative urea test removed S. In order to proceed identification, those cultures were isolated as separate organisms, using inoculating streak technique and incubated until the next class period.
This is deduced by the addition of Reagent A and Reagent B, and the observation of the color change thereafter. The importance of identifying microorganisms is essential to the survival of humans, expansion of modern day medicine and improvement of quality of life. In order to get accurate results the inoculation and separation techniques were conducted again from the beginning, taking tube labeled 117 and using inoculating streak technique. Third, even though it might not protect you completely, wash vegetables as thoroughly as possible. The identification of these unknown cultures was accomplished by separating and differentiating possible bacteria based on specific biochemical characteristics.