Identifying Unknown Bacteri Streptococcus Agalactiae

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

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.

For many years the identification of microorganisms has been important in the world of medicine. It is essential or correct disease diagnosis in patients and for proper treatment. Knowing the correct identity and characteristics of microorganism is crucial when disease outbreaks occur in populations, also knowing how humans can benefit from microorganisms is important; many can be used in making certain foods or antibiotics.

The next step of the project included preparing a Gram stain to discover the cell shape, arrangement, and if the bacteria is gram positive or

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.

There are many reasons for identifying an unknown bacterium. The reasons range from medical purposes, such as determining if the unknown could cause ailments in living things or knowing what microorganisms are needed to make antibiotics to other purposes such as knowing the exact microorganism has to be used to make certain foods. This experiment was done by applying methods in order to identify an unknown bacterium.

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 have been learned so far in the microbiology laboratory class for the identification of unknown bacteria. The identification process can be completed with a series of deferential stains and biochemical tests. Creating a dichotomous key helps to limit the amount of biochemical tests done on an unknown organism and by observation

The unknown bacterium did not produce any spores as was evident by the endospore stain. B. subtilis (positive controls) was capable of producing spores in the NSM agar plate while no spores were formed by E. coli (negative control). The spore-former Sporosarcina was eliminated from the list of the possible genera. In the blood agar test, it was determined that the bacterium was gamma-hemolytic when it was compared to the gamma-hemolytic control S. epidermidis and beta-hemolytic control S. aureus. Since most species of Streptococcus are either alpha or beta-hemolytic, the negative result of the blood agar hemolysins led to the elimination of Streptococcus (8). These tests narrowed the possible genus to

In the world of microbiology it is vitally important to be able to discern the identities of microorganisms. Not only is it important in a lab setting but as well as in healthcare in general. Properly identify what strain of bacteria a person has will aid in the proper medicine and dose given. Throughout the semester we have learned about different types of bacteria and certain test that can clearly identify them. The purpose of this lab report is to identify a Gram-positive or Gram-negative bacterium. Using all the knowledge of procedures and lab techniques identify the unknown and discuss all the tests you performed.

The bases of this experiment was to discover the identify of the unknown from three possible specimens: Klebsiella pneumonia, Escherichia coli, and Enterobacter aerogenes. Utilizaing the T streak technique, the bacteria was isolated into pure colonies for further study. The Gram Stain method was used to identity the morhphology of the bacteria such as the shape and whether the bacteria was Gram positive or Gram negative. Biochemical test were also used to help identify the unknown bacteria. The biochemical test used was the Triple Sugar Iron Agar, Sulfur Indole Motility test, Methyl Red test, Voges-Proskauer test, Citrate test, Urease test, and the Gelatin test. After observing the morphology of the bacteria using the Gram Stain method and utilizing all the possible biochemical test, the bacteria was identified to be Enterobacter aerogenes.

After inoculating an agar plate with the bacteria taken from a phone screen in Durham during winter, various tests were performed to attempt to identify the organism’s genus. We hypothesized that the bacteria was a member of the Staphylococcus genus. The Gram Stain results indicate that the bacterium is either Gram negative, but the KOH test indicates a Gram-positive isolate. Upon further consideration, we decided that the bacterium is a Gram-positive destainer. Gram-positive bacteria have a thick cell wall composed of peptidoglycan. As expected, the Gas Pak and TSA stab results indicate that the bacterium cannot grow in the absence of oxygen. A motility stab indicated that the bacteria were motile. Motility provides an ability to change direction and move away from repellents and toward attractants. Thus, the microbe can avoid unfavorable conditions, and live longer. The positive lysine decarboxylase test indicates that the microbe can use the amino acid lysine as a source of carbon and energy for growth. First, the bacteria use glucose as its primary carbon source, which causes the pH to drop. The enzyme lysine decarboxylase degrades lysine to produce basic products. This change in pH is what causes the broth to turn purple again, a positive result. An endospore stain indicated that the bacterium does not produce spores under stress to protect the cells from dying. Spores are metabolically inactive and

We selected two locations for sample collection: for Site 1 a phone was selected, and Site 2 a desk. One agar plate was labeled “Control” with our group identification number. A sterilized swab was dipped into a test tube with sterile water to wet the cotton on the swab. The culture from the swab was transferred to the surface of an uncultured nutrient agar plate using a zigzag motion. This is to determine if there are any bacteria in

The inner part of the nose and the back of the throat of a group member were swabbed in this experiment, in order to see if the bacteria Neisseria or Streptococcus were present in these locations. The features that make it easy to identify these two types of bacteria are that an oxidase test can be done for the Neisseria bacteria and using a blood agar to identify beta hemolytic species of the Streptococcus. Using the agar plates, the colonies were put through a few tests to see if the bacteria grown was the wanted pathogens or not. A prediction that Staphylococcus aureus would not be found in the nose of the group member, because many people do not possess this certain bacteria as a part of their normal microbiota, and that it would be expected to find the bacteria Neisseria and Streptococcus in throat. The throat is exposed to two places of entry, the nose and the mouth. These two openings allow for more bacteria to enter.

Another plate given was the MacConkey Agar Plate; unknown 11 had been isolated in this plate and incubated for 48 hours under 37o C. There was growth in the plate, punciform, pink pigmentation, raised, undulate margin. Also, Gram staining was also use to determine the morphology of unknown 11. And other test tubes were inoculated to determine the characteristics of what type of Gram negative bacteria is unknown 11. Table 2 shows the result of all tests performed to identify the

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