Aseptic Technique Lab Essay

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.

Step 1: Label the test tubes 1, 2, 3 and 4, where test tube 1 represents the sample placed on the counter at room temperature, test tube 2 represents the tube placed in the refrigerator, test tube 3 represents the tube placed in the freezer, and test tube 4 represents the sample exposed to boiling water. You will expose catalase to each of these four conditions.

In the beginning of lab, we were advised to obtain a nutrient agar petri plate, which is used for the cultivation of microbes supporting growth of non-fastidious organisms. Since it contains many nutrients, a wide variety of bacteria and fungi can grow. Taking the plate,

1. List and describe the sequence steps routinely used to identify bacteria. These are referred to as the “five I’s” in your text.

There are many reasons for knowing the identity of microorganisms. The reasons range from knowing the causative agent of a disease in a patient, so as to know how it can be treated, to knowing the correct microorganism to be used for making certain foods or antibiotics. This study was done by applying all of the methods that I have been learned so far in the microbiology laboratory class for the identification of an unknown bacterium.

9) Trial E: Remove the syringe and empty the beaker. Add a Thermometer to the beaker. Add 200 mL of Room Temperature water to the beaker and heat with a Bunsen Burner until it reaches 100° C. Remove the Bunsen Burner. Repeat Steps 5 & 6.

For the temperature test each bacteria was placed on a nutrient agar and incubated for either 10, 20, 30, 40, or 50 degrees Celsius for 48 hours. During the pH test, each organism was placed on four agars varying in pH level from pH 2, 4, 6 and 8 and incubated near 37 degrees Celsius for 48 hours. For the osmotic pressure test, each organism was placed on four agars one each containing 2%, 5%, 8%, and 11% NaCl concentration levels. These were incubated near 37 degrees Celsius for 48 hours. The results of the tests are recorded in Tables 1, 2, and 3. All tests were performed according to the instructions provided in Leboffe & Pierce(1). The biochemical tests used on both unknowns and the ubiquity are:

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 bacteria based on specific biochemical characteristics. Whether the tests performed identified specific enzymatic reactions or metabolic pathways, each was used in a way to help recognize those specifics and identify the unknown cultures. The differential tests used to identify the unknown cultures were oxidase, catalase, lactose and sucrose fermentation, Kugler/iron agar, nitrate reduction, gelatin hydrolysis, starch hydrolysis, manitol salt, MR-VP, citrate, bile esculin,

An unknown bacterium 15 was awarded and labeled at the table ready to be identified. Using the skills and test that are taught and learned in microbiology were applied into learning what the unknown bacteria culture was. There were multiple procedures and test done in order to gain all the information needed to determine which bacteria was given. In order to find what the bacteria was the first step was finding the right environment and temperature that would allow the bacteria to thrive and grow. Determining this is one of the most important steps in being able to obtain conclusive results that would allow the results of the test to be accurate and correct. Without the correct temperature and environment the bacteria will give inconclusive results which will alter and skew the end results and may lead to the wrong conclusion. By using the methods that were obtained and learned through the microbiology class allowed the skills and knowledge to determine the bacteria and execute the tests in order to determine the culture.

2) Rinse the solid with about 30 mL of distilled water and decant the liquid from the solid. It is critical that as little solid as possible is lost during this process. Repeat the rinsing two or three times.

There are many types of chemical agents that can be used for a variety of effects. Most are not meant to be lethal, but most chemicals at high concentrations can be lethal.

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

This experiment was performed to test the hypothesis if LB nutrient broth, +pGLO and -pGLO Ampicillin, and Arabinose was placed in the E. coli plates, then there will be a significant growth in the newly transformed bacteria and it will possess the ability to glow under UV light. The measurements were recorded from the bent glass tube in each glass test tube. The transformation protocol tested for the newly possessed traits in E.coli bacteria. Throughout the experiment there were many probable reasons for failure. If the pipettes and sterile loop were not thrown out in between each use, a cross contamination could cause a miscalculation in the experiment causing the data results to fail. The hypothesis that was tested was validated due to the positive results with each experiment stating that newly transformed organisms due in fact pass on traits.

Microbial growth can be affected by different environmental factors such as temperature, osmotic pressure, oxygen concentration and pH. Six experiments were carried out in this report testing for microbial growth against different environmental factors. Good aseptic techniques were used to prevent contamination, resulting in a uniform set of results that are in line with the literature.