Coccus Shape

An unknown bacterium was handed out by Dr. Honer. The appropriate tests were prepared and applied. The first procedure that was done was the gram stain. Under a microscope, if the gram stain is purple, the bacterium is gram positive, if the stain is red, it is gram negative. The next test was the fermentation tests for glucose, sucrose and

11. An important tool available in the Virtual Unknown program is the Identification Matrix. From the portion of the identification matrix shown in the Identifying Bacteria tutorial, identify at least one bacterium that has a positive result to the arabinose fermentation test. (1 pt)

The Gram stain was used to determine if the bacteria was gram positive or negative. A negative test shows a pink color and a positive test is a purple color. When a bacterium is negative it is because it has an outer membrane and a thin layer of peptidoglycan that is much harder to stain. A positive bacterium has a thick layer of peptidoglycan and no outer membrane that can be penetrated by crystal violet.

Next I performed a KOH test to further confirm that my organism was a Gram-negative species. For the KOH test, I added 3 drops of 10% potassium hydroxide (KOH) to a small drop of distilled water onto a clean microscope slide, transferred a visible clump of organism to the KOH solution using my inoculating loop. I than mixed the cells into the solution using small, circular motions for 60 seconds and then lifted up the loop to look for what appears to be a “stringing” affect which means it’s confirmed that it is gram- negative species. Next, I created a streak plate using nutrient agar so that I could see pure culture of my organism. I aseptically obtained a loop full of my organism and gently inoculated one quarter of the nutrient agar plate by running the loop back and forth across the surface. I then flame sterilized the inoculating loop, allowing it to cool for 10 seconds, and then streaked the organism from quadrant I into quadrant II using a zigzag motion technique. I repeated those steps streaking from quadrant II to quadrant III and then streaking from quadrant III to quadrant IV. Once completed, I put the streak plate in the incubator at 37° for 24-48 hours. 48 hours later, I check my streak plate and it had a lot of growth on it. I was able to determine that the organism was definitely an off white color, opaque. The IV quadrant was the quadrant that best

The IMViC test is a series of different tests that differentiate between enterics. One is the Indole test. This test tells whether the bacterium possesses tryptophanase which is the enzyme that breaks down tryptophan into indole. The agar contains tryptic soy broth so if the bacterium contains tryptophanase, indole is produced. This production of indole is seen by adding Kovac’s reagent which causes a red ring to be seen at the top of the tube. The citrate test is also used to see which kind of products the bacteria make. It uses a green agar slant that contains sodium and ammonium phosphate. Bromythymol blue dye is late added as an indicator. Inoculation of the slant with a needle using a zig-zag then stab technique was used with the gram positive bacterium. Conversion of the medium to blue is a positive citrate result. All plates, slants, and broths were incubated at 37°C for 24‐48 hours.

The main idea of this experiment was to correctly identify the unknown bacteria, #3. Identification of unknown bacteria yields multiple benefits in many different areas in the research of microorganisms. In this experiment I performed many different test dealing with things such as the presence of enzymes, fermentation abilities and different chemical reactions. Observations made from the tests were then compared to a gram negative unknown chart in order to identify the bacteria. Based off of my results and the chart, I concluded the bacteria #3 was the bacteria Escherichia coli. E. coli is most commonly found in the intestines of warm blooded organisms. Most E. coli strands are non pathogenic however, there are strands

This experiment was given to us to utilized previous knowledge learned throughout the semester to identify a gram negative unknown bacterium. We had to first learn the difference between a gram negative and a gram positive organism. We started off with doing gram stains to determine whether it was positive or negative. Based on the gram stains, a gram positive stains purple and a gram negative stains pink. A gram positive stains purple because the cell walls is made of a thick peptidoglycan layer and doesn’t

Lastly, safranin was added to flood the slide and was left on for 1 minute and rinsed with distilled water. After adding all 4 reagents, the slide was blotted dry with a paper towel to remove any excess reagents or water. The slide was then placed on a microscope stage to look for the color of the bacteria. When ready for the highest power on the microscope, immersion oil was added to the slide and looked at under 100x power. A glucose test and citrate test were found to be the best two tests to help narrow down the bacteria.

In class, we were given the task of identifying an unknown bacterium broth culture. After receiving number 69, I went through several tests to figure out what bacterium I received. First, I created a slide from my broth by putting a small amount of the unknown broth on to a clean slide and letting it dry for ten minutes. After this, I stained the slide by applying four reagents in order; crystal violet, grams iodine, decolorizer and safranin. From the stained slide, I discovered that this bacterium was gram-negative, which would determine the next couple of tests I would do to identify my unknown bacterium. I began by streaking for confluent growth from my broth culture onto a TSA plate. From the TSA plate, I aseptically transferred a loop

I did not have a gram positive rod as one of my unknowns but in order to complete the key fully, I examined which metabolic test would distinguish between Bacillus subtitles and Corynebacterium xerosis. I chose an Amylase test. Bacillus subtitles would produce amylase, breaking down the starch into glucose, generating a positive result. On the other hand, Corynebacterium xerosis would not produce amylase, generating a negative result. With that test I would be able to identify which one could have been the unknown bacteria. However, I did have a gram positive cocci as one of my unknown bacteria. I first decided to do a lactose fermentation test because a negative result would identify my bacteria as Micrococcus gluteus, and a positive result would indicate that I was working with either Staphylococcus aureus or Streptococcus faecalis. If the results were positive, I would have to pick another test to distinguish between

An unknown test tubes labeled P and 11 was given out by the lab instructor. The goal was to determine two separate unknown bacteria, one gram- positive and one gram-negative. This technique was used by gram staining. The purpose of gram staining is to determine whether bacteria are present. Also, the structure of the organism’s cell wall determines whether the organism is gram positive or negative. My unknown test tube P was gram positive because the bacteria retained the primary stain, while my unknown test tube 11 was gram negative because it was decolorized and counterstained. Test tube P had small cocci’s in clusters and chains, while test tube 11 had small rods in clusters.

I chose TSA agar plate number 33 for my unknown ID. First, I made a streak plate of my bacteria in case I needed more later. Then, I performed the Gram’s stain. The Gram’s stain results were a very dark purple stain and small round clusters of bacteria. This led me to believe I had a Gram-positive cocci. Nothing went wrong with this test, the test was without a doubt positive (very dark purple), and I was very happy with how it turned out. With that information, and after looking at the Unknown ID flow chart directions given to us in the course, I decided to do a catalase test and dropped the 3% hydrogen peroxide straight on my original agar plate because there is no other option for cocci in this project, especially Gram-positive cocci. The

Streptococcus agalactiae also called group B streptococcus (GBS) by Lancefield classification. GBS is gram-positive coccus that tends to form chains, and is part of the normal flora of the genitourinary tract. GBS is a leading cause of newborn early onset disease (EOD)[1, 2], and has highly morbidities and mortality rate[3]. It also associated with invasive disease in adult especially older people over 65 ages[4]. When GBS infects of blood it cause sepsis, infection in the lungs causes pneumonia, infection in the fluid and lining around the brain will cause meningitis[5]. GBS capsular polysaccharide (cps) is the most important virulence factor and now there is ten capsular serotypes have characterized[6], serotypes Ia, Ib, II, III, IV,

After observing the results that were conducted on the unknown #222. It was determined to be Micrococcus luteus. Most of the tests observed on M. luteus had a match with the expected result, except for two tests. Those tests were the determination of glucose fermentation, and the oxidase test.

Determination of the bacteria being a lactose fermenter or non fermenter is done through the growth on the MacConkey agar. Knowing this allow for the student to perform the necessary tests to determine which lactose fermenter was present in the sample. The Indole test allows for the determination of whether the unknown bacteria is Escherichia coli because this genus and speices is the only lactose fermenter that will produce a positive result here. Moving onto the Methyl red test this indicates glucose fermentation, more specifically microbes that produce mixture of acids as a result of fermentation. The Voges-proskauer tests for glucose fermentation, specifically organisms whose acid is converted to acetoin. The Citrate test differentiates an organism’s ability to use citrate as its only carbon source. The urea broth culture detects the enzyme urease, which allows break down of urea producing acid, which causes a noticeable change in color. The final test is the motility test to determine if the bacteria has the capacity of movement beyond the point of