Ms Plate Trial Case Studies

The purpose of this experiment is to investigate the effects of various household products may have on bacterial growth. The bacteria that was chosen as a test subject is Micrococcus luteus, which is generally considered a harmless bacterium unless the host has a weakened immune system. Among the household products that a set of groups will test are common cleaning and disinfecting products such as rubbing alcohol, Betadine, Germ-X, Neosporin, liquid hand soap, and Lysol cleaner. In the experiment, the bacterium, Micrococcus luteus, is to be swabbed and grown in a Petri dish divided into four sections with agar in each. After that, a small circle of thin paper is soaked in the four household items. Then, a piece of parafilm

9. After the 48 hour time period the inhibition of the Escherichia coli bacteria around the disinfectant disks was measured. A ruler was used to measure the clearing from the edge of the disk to the perimeter of the clearing. Irregularities in the clearing were not included in the area of clearing.

This experiment was conducted to find the genus and species of an unknown bacteria prescribed by the lab teacher, which was unknown bacteria GA3 in my case. Identification of unknown bacteria techniques are used on an every day basis to figure out what type of bacteria it is and to find the best method of how to treat a patient with this bacteria (1). All five “I’s” of Microbiology were used in the testing for the unknown culture. Inoculation was used several times to put the unknown culture into agar plates or into biochemical test tubes. After Inoculation of these tubes or plates, they always were placed into the incubator for further growth and development. Isolation was used to make sure we got the correct bacteria we were testing for. After each further isolation, we gram stained the culture and inspected the culture under a microscope to further help in the identification process of the unknown bacteria. Multiple tests were done on the unknown culture to make sure we were confident in what kind of bacteria the unknown was.

In this experiment, an unknown bacterium was given to each individual student. The main purpose of this lab was to identify the given unknown bacteria going through a series of biochemical tests as one of the gram negative bacteria among six different Gram negative bacteria Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Salmonella typhimurium. At the very beginning, streaking method; T-streak technique was used to isolate the pure colonies. For the morphological identification of unknown bacteria, Gram Stain Method was done. Biochemical tests that were conducted for the experiment

70µL of competent E.coli are added to both test tubes; pUC18 and Lux (Alberte et al., 2012). Both test tubes are then tapped and placed back into the ice bath for 15 minutes. While waiting, another test tube is obtained, filled with 35µL of competent cells and labeled NP for no plasmid. A water bath is preheated to 37 degrees Celsius and all three labeled test tubes are inserted into the bath for five minutes (Alberte et al., 2012). Using a sterile pipet 300µL of nutrient broth are inserted into both the control and Lux test tubes and 150µL are inserted to the no plasmid test tube to increase bacterial growth. All three test tubes are then incubated at 37 degrees for 45 minutes. Six agar plates are obtained and labeled to correspond each test tube, three of the plates contain ampicillin. A pipet is used to remove 130µl from each test tube containing a plasmid and insert it into the corresponding agar plate. For this, a cell spreader is first

MSA agar is selective and differential medium which was used to see if the bacteria fermented mannitol or not. Selective because it selects for gram positive bacteria specifically Staph. species and it has 7.59% NaCl which means the bacteria must tolerate high concentrations of salt to grow and differential because it has a mannitol phenol red pH indicator. After running most of the test, I was able to conclude that my gram positive unknown is either Staphylococcus aureus or Staphylococcus epidermis. To differentiate between the two MSA agar was used because Staphylococcus aureus ferments mannitol and should have growth because it is a gram positive bacteria but Staphylococcus epidermis does not ferment mannitol but can have growth on the agar. So, using aseptic technique, I split the plate in half and inoculated my 2 unknowns onto MSA plate, then incubated at 37 for 24 hours. I knew my unknown A would not grow because it is a gram negative bacteria but it was inoculated as a control to make sure the test is running properly. When I came the next day, the gram-positive bacteria of my plate had growth and the color changed from red to yellow indicating that the bacteria fermented mannitol, which produced acid lowering the pH of the medium. Gram-positive bacteria had yellow color growth and it was surrounded by a yellow halo and gram-negative bacteria did not have any growth and the agar was still red in

On August 19th, 2015 this experiment was performed, by 6 separate lab groups.The experiment began by measuring 1 Ml of E. coli into a pipette and pump, then placing the bacteria into a culture medium. The E. coli and medium were then swirled together for a period of 15 minutes, until completely mixed. This mixture was then poured into a petri dish and allowed to solidify for 45 minutes. After the 45 minute solidification time, 5 small paper disks were inserted into the dish. 4 of the disk contained treatments of antibiotic and 1 was left untreated. The

When streaking bacteria and handling mannitol and xylitol solutions, the experimenter wore an apron, nitrile gloves on both hands and plastic protective goggles. After each set of plates were prepared, the experimenter removed the gloves from both hands without skin contact and thoroughly washed their hands for approximately 20 seconds with soap and warm water. Throughout the entire experiment the experimenter was cautious also to avoid contacting bacteria with eyes, mouth, or open wound.

There of the dishes turned out as expected in this experiment. Our group expected there to be growth in the LB -pGLO dish as the bacteria were not exposed to the antibiotic ampicillin. Furthermore, our group also expected to see inhibited bacterial growth in the LB/amp +pGLO dish as there was ampicillin in the dish, but some of the bacteria were immune as they possessed immunity to the ampicillin. Moreover, our group expected that there would be no bacterial growth in the LB/amp -pGLO dish, as the bacteria were exposed to ampicillin and were not immune. However, the final dish, LB/amp/arbo +pGLO, did not turn out as expected. While it was expected to allow for inhibited bacterial growth and the bacteria to become florescent,

You can grow microorganisms in liquid media or on solid media. Most bacteria can be grown in labs as long as the media contain a source of the major nutrients; carbon, nitrogen, sulphur, and phosphorous. They may also need to have other nutrients. These nutrients are made into a broth and the pH and salinity can be adjusted. The nutrient broth is placed in test tubes, which are plugged with cotton wool, capped with foil and then sterilised in an autoclave, at 121c for 20minutes. These tubes are then cooled before they are inoculated. To prepare the streak plates we dipped an inoculating loop into ethanol then placed it in the flame until the loop glowed red. Still holding the inoculating loop by its handle we removed the lid from

The medias used in the experiment were the EMB agar and LT broth. LT broths are a selective/differential medium which contains sodium lauryl sulfate which is a detergent that stomach and intestinal bacteria have the ability to withstand. LT broths also contain lactose that supoorts coliform growth by fermentation. EMB agars are differential mediums that contain dyes that are inhibitors of Gram-positive organisms. They also produce dark colored colonies around

In the first part of the experiment, we plated donor bacteria, which was chloramphenicol resistant, on a Nal plate. Because no donor bacteria would grow on a Nal plate, this was a way of ensuring that the sample of donor E. Coli bacteria was pure.

If sterilization was not used in my experiment the results would be inaccurate. This would be caused by having additional bacteria on plates that was not oral bacteria. The additional bacteria is from contamination of other types of bacteria on tools I used came in contact with. Using sterilization I was able to kill other types of bacteria that was on the tools before I used them on my bacteria. Using clean tools you can have more precise results on how well my mouthwashes worked.

Nutrient Broth and Nutrient Agar were used to inoculate bacteria taken from different surfaces. Nutrient agar plate was inoculated with a sample taken from skin surface. A sterile cotton swab was first immersed on sterile water, then, rubbed against the skin with swirling motion and transferred to an agar plate by rubbing

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.