What Is Enterococcus?

Three ways to assess water are positive/negative, membrane filtration and IDEXX Colilert and Enterolert assays. For membrane filtration, petri dishes and an incubator are used. For IDEXX coliert powdered medium is used for total coliform and E. Coli, while Enterolert media is used for enterococci. Also an incubator, colilert trays are used. IDEXX is more expensive than membrane filtration.

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

Using the information found in the Gram Negative Enteric Baccilli and Gram Positive Cocci Reference books,

According to the “Microbiology Laboratory Manual,” lab 27 focuses on the family Enterobacteriaceae, this is one of the largest families of bacteria (Wong et al., n.d.). Also all of the members are gram-negative, anaerobe straight rods and can commonly be located in mammal’s intestines (Wong et al., n.d.). All the members Enterobacter aerogenes throughout this report will be referred to as, E. aerogenes. There were several examples where E. aerogenes was tested or used, the first example is a One-pot synthesis, the next example is where it is used for dark fermentative biohydrogen production, and the last example is where it is analyzed in groundwater in North Central Nigeria.

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.

Bacteria are ubiquitous; they can be found on the skin, in the soil, and inside the body. Because of the very nature of this ubiquity, it is important to be able to determine between different strains of bacteria. An example of this is determining the causative agent for a disease so that the patient will be treated with the appropriate antibiotics. It may be important to determine the bacteria in a certain region, because like with enteric bacteria, it is normal to find them in the digestive tract as they are in a symbiotic relationship with our bodies in this area; however, they also cause opportunistic infections in places outside of the digestive tract to our detriment, such as with a urinary tract infection. Some strains of bacteria are common to nosocomial infections, and identifying these bacteria as such helps create the guidelines for healthcare workers in antiseptic technique. All of the morphology and characteristics of each strain of bacteria help us to better understand the role of bacteria in the body as well as helps us understand how they can cause illness, and what treatment regimen to set in place. In lab this semester, a sample of unknown

I inoculated a T-Soy agar with bacteria number 118, for this I used a streak isolation method. Next, in order to distinguish between Gram positive and Gram negative I used a streak isolation technique on a CNA plate, then performed the same exact procedure on a MacConkey plate. The results from the CNA plate showed the Gram Positive bacteria was an Alpha hemolyzer. Next, I used a P Disc on a T-Soy agar inoculated with bacteria 118 and determined the Gram Positive bacteria was not sensitive to P Disc antibiotics. This revealed the Gram Positive bacteria to be Streptococcus Mitis. The results from the MacConkey plate proved the Gram Negative bacteria to be a lactose fermenter. With the Gram Negative bacteria I performed a lysine test with positive results. Next, I performed an ornithine test on the Gram Negative bacteria, with negative results, therefore I concluded the Gram Negative bacteria was Klebsiella pneumoniae.

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

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

The species ID from the Biolog was confirmed to be Staphylococcus epidermidis with a probability of 99.2%. The observed results of utilization of D-Mannitol, citric acid, D-fructose, and α -D-lactose matched the expected results. The bacteria sensitivity to NaCl differ from the expected results; the bacteria should be tolerant to NaCl up to 10-15%. The fermentation results of glucose and lactose from phenol red broth was different from the results observed in the Biolog. The Biolog results matched the expected results for S. epidermidis with a few exceptions. From the citrate slant test, it was observed that the bacteria was unable to utilize citrate; however, the observed results from the Biolog test was inconclusive indicting a positive and negative result. The bacteria was indicated to not be sensitive to Vancomycin, however, the bacteria is expected to be sensitive to the antimicrobial

Escherichia is a genus of aerobic gram-negative rod-shaped bacteria of the family Enterobacteriaceae that form acid and gas on many carbohydrates, such as dextrose and lactose, but not acetone, which include occasional pathogenic forms, including some strains of E. coli which are normally present in the human intestine as well as other forms which typically occur in soil and water (Webster). Escherichia coli is a gram-negative bacilli that rarely varies in shape and size and when stained often resemble safety pins because the ends of some bacilli stain more densely than does the middle; which is a characteristic called bipolar staining which is common in enteric gram-negative bacilli (ASM). Gram negative cells have a thin cell wall layer and will stain red to pink. The staining process is the same as Gram positive, requiring four steps: applying a primary stain, adding a mordant, then rapid decolorization and completing with a counter stain. Applying the alcohol for decolorization dissolves the outer membrane and leaves small holes in the thin peptidoglycan layer through which the crystal violet-iodine diffuse. The gram-negative bacteria is colorless after the decolorization; therefore adding safranin

2. Introduction: Each student was given unknown bacteria and was instructed to perform a variety of experimental tests that would help to identify their bacteria. During the process of identification, the unknown bacteria was added to many different testing medias using aseptic technique. They are as follows: lactose fermentation on eosin methylene blue (EMB), TSI (Triple Sugar Iron agar), Phenol red sucrose, the SIM test, H2S by SIM, IMViC (indole, motility, voges-proskauer, and citrate), Urease (urea broth), PDase (Phenylalanine Deaminase), Lysine Decarboxylase, and Ornithine Decarboxylase. Colonial morphology on EMB was used to

Each mixed culture that was tested had one gram positive and one gram negative bacterial species. The possible species of bacteria that could have been isolated from the mixtures included the following: Bacillus subtilis, Corynebacterium glutamicum, Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Enterobacter aerogenes, Salmonella enterica, and Pseudomonas aeruginosa. The identities of the unknown species were determined through comparing the experimental data against data acquired from earlier experimentation.

The results from table one shows the optimal temperatures for Escherichia coli is 37-45°C, Pseudomonas fluorescens 25°C and Enterococcus faecalis 37°C. This supports the fact that these three bacteria are classed as mesophiles. Enterococcus faecalis are commonly found in the gastrointestinal and female genital tract of humans, also Escherichia coli is located in the lower intestine. The optimum temperature of humans is 37°C which serves as a perfect host for them. Pseudomonas fluorescens are located in soil, plants

Broth cultures of E.coli, Micrococcus luteus and Vibrio natriegens were streaked onto the respective sections. The plate was then incubated at 37oC for 48 hours. The process was then repeated on nutrient agar plates with 5, 6.5 and 10% salt.