IDENTIFYING CITROBACTER FREUNDII THROUGH BIOCHEMICAL TESTING.
Jebin Jacob
November 15th, 14
Naghmeh Hassanzadeh
Unknown - 10
Purpose
The purpose of this study is to identify an unknown bacterium from a mixed culture, by conducting different biochemical tests. Bacteria are an integral part of our ecosystem. They can be found anywhere and identifying them becomes crucial to understanding their characteristics and their effects on other living things, especially humans. Biochemical testing helps us identify the microorganism present with great accuracy. The tests used in this experiment are rudimentary but are fundamental starting points for tests used in medical labs and helps students attain a better understanding of how tests are conducted in a real lab setting. The first step in this process is to use gram-staining technique to narrow down the unknown bacteria into one of the two big domains; gram-negative and gram-positive. Once the gram type is identified, biochemical tests are conducted to narrow down the specific bacterial species. These biochemical tests are process of elimination that relies on the bacteria’s ability to breakdown certain kinds of food sources, their respiratory abilities and other biochemical conditions found in nature.
The results of these tests prove that the unknown organism is Citrobacter freundii hereby referred to as C. freundii. C. freundii is a member of the Enterobacteriaceae family, like all the other unknowns given in this test. The species is a facultative anaerobic and is a gram-negative bacilli. C. freundii is a non-spore forming, motile bacteria that are long rod-shaped with a typical length of 1-5 μm.
The seven biochemical tests conducted to narrow down the gram-negative stain are Phe...
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...dentifying unknown bacteria are and its implications for humans and nature.
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Table 6 shows the results of the biochemical tests. The isolate can obtain its energy by means of aerobic respiration but not fermentation. In the Oxidation-Fermentation test, a yellow color change was produced only under both aerobic conditions, indicating that the EI can oxidize glucose to produce acidic products. In addition to glucose, the EI can also utilize lactose and sucrose, and this deduction is based on the fact that the color of the test medium broth changed to yellow in all three Phenol Red Broth tests. These results are further supported by the results of the Triple Sugar Iron Agar test. Although the EI does perform fermentation of these three carbohydrates, it appears that this bacterium cannot perform mixed acid fermentation nor 2,3-butanediol fermentation due to the lack of color change in Methyl Red and Vogues-Proskauer
The first day an unknown sample was assigned to each group of students. The first test applied was a gram stain to test for gram positive or gram-negative bacteria. The morphology of the two types of bacteria was viewed under the microscope and recorded. Then the sample was put on agar plates using the quadrant streak method for isolation. There were three agar plates; one was incubated at room temperature, the second at 30 degrees Celsius, and the third at 37 degrees Celsius. By placing each plate at a different temperature optimal growth temperature can be predicted for both species of bacteria.
In this lab project, the microbiology students were given 2 unknown bacteria in a mixed broth each broth being numbered. The goal of this project is to determine the species of bacteria in the broth. They had to separate and isolate the bacteria from the mixed broth and ran numerous tests to identify the unknown bacteria. The significance of identifying an unknown bacteria is in a clinical setting. Determining the exact bacteria in order to prescribe the right treatment for the patient. This project is significant for a microbiology students because it gives necessary skills to them for future careers relating to clinical and research work.
Barone, Eugene J., Judson C. Jones, and Joann E. Schaefer. "Hidradenitis Suppurativa." Skin Disorders. Philadelphia: Lippincott Williams & Wilkins, 2000. 21-25. Print.
The purpose of this laboratory is to learn about cultural, morphological, and biochemical characteristics that are used in identifying bacterial isolates. Besides identifying the unknown culture, students also gain an understanding of the process of identification and the techniques and theory behind the process. Experiments such as gram stain, negative stain, endospore and other important tests in identifying unknown bacteria are performed. Various chemical tests were done and the results were carefully determined to identify the unknown bacteria. First session of lab started of by the selection of an unknown bacterium then inoculations of 2 tryptic soy gar (TSA) slants, 1 nutrient broth (TSB), 1 nutrient gelatin deep, 1 motility
The Gram stain is a system used to characterize bacteria based on the structural characteristics of their cell walls. A Gram-positive cell will stain purple if cell walls are thick and a Gram-negative cell wall appears pink. Most bacteria can be classified as belonging to one of four groups (Gram-positive cocci, Gram-positive bacilli, Gram-negative cocci, and Gram-negative bacilli) (Phenotypic analysis. (n.d.).
Bacteria play a large role in our health, the environment, and most aspects of life. They can be used in beneficial ways, such as decomposing wastes, enhancing fertilizer for crops, and breaking down of substances that our bodies cannot. However, many bacteria can also be very harmful by causing disease. Understanding how to identify bacteria has numerous applications and is incredibly important for anyone planning to enter the medical field or begin a career in research. Having the background knowledge of identifying an unknown bacteria may one day aid healthcare professionals diagnose their patient with a particular bacterial infection or help researchers determine various clinical, agricultural, and numerous other uses for bacteria.
Clostridium perfringens is a gram-positive spore-forming bacillus involved in foodborne illness and wound infection. It is an obligate anaerobe and the only member of the genus Clostridium that is non-motile. This microorganism is normally present in soil and decaying vegetation and is an inhabitant of animal and human intestines. According to the Centers for Disease Control and Prevention, C. perfringens is one of the most common sources of foodborne illness in the United States, being the cause of an estimated 1 million cases each year. However, it is also prevalent worldwide. This bacterium has the shortest reported generation time of any organism at 6.3 minutes in thioglycollate medium, making it particularly virulent after initial inoculation.
I identified the genus and species of an unknown bacterial culture, #16, and I applied the following knowledge of morphologic, cultural and metabolic characteristics of the unknown microorganism according to the laboratory manual as well as my class notes and power point print outs. I was given an incubated agar slant labeled #16 and a rack of different tests to either examine or perform myself; the tests are as follows: Gram Stain; Nutrient Gelatin Test; Carbohydrate Fermentation; Dextrose, Lactose and Sucrose; IMVIC tests; Citrate, Indole, Mythel-Red and Vogues Proskauer test; as well as a Urease and TSI Test.
coli for testing of protein expression. Initial tests confirmed the expression of both proteins, with P3H1 being expressed in lower amounts compared to CRTAP. I will continue with Dr. Morello to conduct expression tests in different E. coli types until I obtain optimal expression of both proteins. Because patients with recessive forms of osteogenesis imperfecta typically have an incomplete CRTAP/P3H1 complex, an artificial drug is a possibility in the future for said patients to reestablish the function of the complex. Once the structure of the CRTAP/P3H1 complex is understood, similar components can be derived to reestablish the function of an incomplete CRTAP/P3H1 complex. A bacterial strain that can optimally express both CRTAP and P3H1 simultaneously is the current major stepping stone. Upon completion of a high expression of both CRTAP and P3H1, larger quantities of the CRTAP/P3H1 complex will need to be purified and analyzed for a crystal structure by a crystallographer, whom has already been contacted and informed of the project and
The history of Ab starts when “the Dutch microbiologist, Beijerinck, first isolated the bacteria from soil using minimal media enriched with calcium acetate, in 1911” (Aoife et al. 244). From there different characteristic of Ab were noted, such as, “Ab is often found in pairs, does not use oxygen, does not produce nitrites, does not move, and it can be isolated on a MacConkey agar, which is a specific media of petri dish” (Rosenbaum et al. 10). Using a staining method, it is determined that Ab is a gram-negative bacterium, because it does take on the stain. Although, Ab can be difficult to de-stain, making it harder to distinguish between gram-negative or positive (Aoife et al 244). “It also has the ability to survive longer in any environment, even on dry surfaces, because it is resistance to desiccation, or being completely deprived
Schepis, Carmelo, Donatella Greco, and Corrado Romano. "Cardiofaciocutaneous (CFC) Syndrome." Australasian Journal of Dermatology 40.2 (1999): 111-13. Print.
...reasingly diverse microflora. Bridging refers to the observation that two non-coaggregating strains may participate together in a multi generic aggregate if they recognize a common partner by distinct mechanism. Fusobacterium nucleatum is believed to be important in bridging between primary and secondary colonizers during plaque maturation. Examples of interaction of secondary colonizers with early colonizers are Fusobacterium nucleatum with Streptococcus sanguis; Provotella loescheii with Actinomyces viscosus. The examples of interaction among secondary colonizers are F. nucleatum with P. gingivalis; F. nucleatum with Treponema denticola.
Leboffe, M. J., & Pierce, B. E. (2010). Microbiology: Laboratory Theory and Application, Third Edition 3rd Edition (3rd Ed.). Morton Publishing