Enterococcus Faecalis: A Comparative Analysis

See Table 1 and Flow Chart 1 for results of Bacteria # 1 and Table 2 and Flow Chart 2 for results of Bacteria # 2.

Table 1: The area of inhibited growth of E.coli at increasing Dettol concentrations shown by the distance of clearing from the soaked disk

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,

In the LB (pGLO negative), it is expected to not see any colonies growing. As a result of this experiment, it shown any growth colonies but this only had shown a large number of white, circular colonies that were found across the surface of the agar. In the LB/Amp (pGLO negative), it is expected to see any growth colonies. In the experiment, the resulted was no growth colonies because this has Ampicillin and no pGLO. Now, the LB/Amp (pGLO positive), it is expected to have growth colonies in the agar plate. As a result, it was shown growth colonies in the agar plate because has positive pGLO regardless having Ampicillin. In the other hand, both positive pGLO have the same components but in one plate was added Arabinose. The LB/Amp/Ara (pGLO

AIM – The aim of the experiment is to determine the relative effectiveness of several anti-microbial substances on developing pathogens. (E. coli)

The first result of importance was the result of the Gram stain. The observations of the unknown bacteria from the slant culture after Gram staining showed that the unknown bacteria were Gram negative bacilli (Image 1). After determining the unknown bacteria was Gram negative, an oxidase test was conducted on a sample from the slant culture. The cotton swap with the sample of bacteria did not change color when the oxidase reagent was applied, thus providing a negative result. With a negative oxidase test, further tests were conducted to determine various characteristics of the unknown bacteria. A MR-VP broth was inoculated with a sample from a slant culture of unknown bacteria. After incubation, the methyl red reagent was added to the broth, and the broth turned red, providing a positive result (Image 2). An EMB agar streak plate was inoculated with a sample from a slant culture of the unknown bacteria, and after incubation, growth was found on the plate, providing a positive result (Image 3). A Citrate agar slant was inoculated, and after incubation, growth was found on the media, providing a positive result (Image 4). A Urea agar slant was inoculated, and after incubation, the agar had changed from a peach color to a bright pink color, providing a positive result (Image 5). Using the flowchart (Figure 1) developed from the Table of Expected Results, the lab partners started at the oxidase test. Given the negative result of the oxidase test, the flowchart is

Nitrate reduction was tested for by inoculating a nitrate broth with the unknown gram (-) culture, and allowing growth to take place. Adding 2 drops of both sulfanilic acid and α-napththylamine to the medium if the first test to see if nitrite is present. If nitrite is present, the medium turns red, indicating a positive test. However, if the medium does not change, a second test is performed to see if nitrite was further reduced. In this second test, zinc powder is added to the broth to catalyze the reduction of any nitrate present to nitrite. If nitrate is present when the zinc is added the reduction of this compound will cause the medium to turn red, from the previously added reagents. Red medium on the second addition indicates nitrate was not reduced and a negative test result. However, if the medium does not change after the addition of the zinc, the unknown is positive for nitrate reduction, as the nitrite has just been further reduced, preventing its detection. The result that yielded was positive on the first step.

2. Which antibiotic was most effective in killing the bacterial lawn on each plate? Which was the least effective?

Many tests were completed on the unknown such as gram staining and inspection under microscopes to find whether the bacterium is gram positive or gram negative. Chemical resistance tests were also performed to see if certain chemicals affected the unknown growth or if it didn’t affect the bacteria at all. Each biochemical test

With NIT 3 probes hybridized bacteria could not be detected, thus either hybridization was unsuccessful or nitrate reducing activity by the NIT 3 gene was not present in the samples. Showing fewer artifacts, the Ntspa 662 probe showed no positive hybridization. Ntspa 662 is specific for the genus Nitrospira, which is known to conduct nitrite oxidation. For the BS 820 probe, which is specific for Candidatus Scalindua wagneri and C. S. sorokinii, no hybridization to bacteria was found, while for the more general probe Sca 1309 just one very small colony of Candidatus Scalindua specimen could be detected (figure 15, J - L) and a very high abundance of anammox bacteria of the genera Kuenia stuttgardiensis or Brocadia anammoxidans was verified using AMX 820 probe, especially in the seeding sludge samples. Thus the majority of anammox bacteria in the seeding sludge are not of the genus Candidatus Scalindua. Besides the positive FISH results, the shape of bacteria hybridized with AMX 820 was similar to what was initially seen with DAPI. Fluorescence reveals ring and sickle shapes (cf. figure

Similarly, the recipient E. Coli bacteria is resistant to nalidixic acid, and would be able to grow on a Nal plate, but not on the Cm plate. By plating the recipient bacteria on chloramphenicol, we can ensure that the sample was purely recipient if there is no growth.

The Kirby- Bauer method is used to test antibiotics sensitivity to the microbe. Some antibiotics have broad-spectrum effect, which means they inhibit the growth of more than one microbe; while narrow spectrum only have an effective on one group of microbe. In order for this test to be effective a lawn of bacteria has to be made on Mueller- Hinton agar. This agar does two amazing things in the world of science. It contains a starch that makes it test plate transparent (easy to read results) and it control the rate of diffusion of the tested drug. Ampicillin, Gentamicin, Gentamicin, penicillin, and vancomycin are the fours types of antibiotics that were use to test the sensitivity of the microbe to them. The microbe was resistant to Ampicillin;

The bacteria that was contained within Unknown tube #12 is believed to be Pseudomonas aeruginosa, Figure 1. The bacteria tested to be Gram Stain negative, producing a pink, red color retained from the staining process. When the species of bacteria was plated on nutrient media, the cells produced an irregular and spreading configuration as shown in Figure 2. This same plating test provided the margins and elevation, lobate and hilly, respectively. The specimen was stabbed in a Fluid Thioglycollate Medium (FTM) tube using an inoculated loop of the bacteria. The results of this experimentation indicate the type of oxygen requirement of the bacteria. The test found the bacteria to be aerobic as colonies of the bacteria began to form along the top of the FTM tube (Manual 2017).

Out of the three antibiotics tested on Staphylococcus aureus erythromycin had the largest zone of inhibition compared to amoxicillin and penicillin. Erythromycin had a 24mm large zone of inhibition, while penicillin had a zone of 9mm and amoxicillin had a zone of 12mm. However when testing Hemophilus influenzae penicillin had the largest zone of inhibition. For penicillin the diameter of the zone of inhibition was 28mm, amoxicillin had 27mm and erythromycin had 16mm. With that being said, for

The main objective of this experiment is to investigate the effect of different types of antibiotics on bacteria Bacillus subtilis and Escherichia coli. Some of the main methods used in this experiment