Unknown Microbiology Report

This is important in the medical field because identification of unknown bacteria can help treat a patient by knowing the contributing source of a disease. Also knowledge of different bacteria helped others make antibiotics used today. This lab was completed by using the methods learned thus far in identification of bacteria.

This experiment was centered on metabolic and biochemical testing procedures. The rationale of performing these tests was to distinguish six different microbes from one another and to compare how their metabolic and biochemical processes differ from species to species to determine the unknown sample.

The purpose of this lab was to identify two unknown bacteria from a mixed culture. The reason for identification of unknown bacteria was to help students recognize different bacteria through different biochemical tests and characteristics. This is important in the medical field because identification of unknown bacteria can help treat a patient by knowing the contributing source of a disease. Also knowledge of different bacteria helped others make antibiotics used today. This lab was completed by using the methods learned thus far in identification of bacteria.

Often scientists work with bacteria that do not come in a labeled test tube— for example, bacterial samples taken from infected human tissue or from the soil—and the scientist must then identify the unknown microorganism in order to understand what behavior to expect from the organism, for example, a certain type of infection or antibiotic resistance. However, because of the relatively few forms of bacteria compared to animals and because of the lack of bacterial fossil records due to their asexually reproductive nature, the taxonomy used to classify animals cannot be applied to bacteria (Brown 275). In order to classify unknown bacteria, a variety of physiological and metabolic tests are available to narrow a sample down from the fathomless number of possibilities into a more manageable range. Once these tests have been performed, the researcher can consult Bergey’s Manual of Determinative Bacteriology, a systematically arranged and continually updated collection of all known bacteria based on their structure, metabolism, and other attributes.

The purpose of this lab was to identify two unknown bacteria cultures using various differential tests. The identification of these unknown cultures was accomplished by separating and differentiating possible

My unknown organism #6 is Morganella morganii, which is a gram-negative bacillus rods commonly found in the environment and also in the intestinal tracts of humans, mammals, and reptiles as a normal flora. (3, 5) This bacterium Morganella morganii, was first discovered in the 1906 by a British bacteriologist named H. de R. Morgan. (2) Despite its wide distribution, it is an uncommon cause of community-acquired infection and is most often encountered inpostoperative and other nosocomial settings. (2, 3) Morganella morganii infections respond well to appropriate antibiotic therapy; however, its

|EMB Agar | |Distinguishes bacteria that ferment |Dark blue colonies with|E. coli and P. |

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 investigation, the objective was to preform various test which were used to help identify an unknown bacterium. The tests done were a combination of selective and deferential media, plus a number of metabolism tests. The result of each test revealed a particular characteristic of the unknown bacterium, and using the combined results observed of these test the unknown bacterium was identified.

The identification of an unknown sample, particularly in the environment, can be the matter of life or death. Identifying an unknown environmental sample has countless of opportunities and benefits. Identifying pathogens in the environment can save the lives of thousands or even millions of people. Some bacteria are opportunistic pathogens such as Pseudomonas. These pathogens do not commonly infect healthy people, but rather take any opportunity possible such as an open wound or an immunocompromised system. Knowing the bacteria which can prevent or promote the growth of agriculture can help to feed populations. Being able to identify bacteria is a task not to be taken lightly. Many different tests are possible to determine a specific bacterium. Often it takes a combination of several different tests to narrow down and identify a specific genus and species.

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 next step in identification was to run a TSI test to determine whether or not the bacteria were able to ferment lactose, sucrose, and/or glucose and if Hydrogen Sulfide was produced by the bacteria. The TSI agar was stabbed with the pale pink bacteria and the slant was streaked. Following incubation, the slant was red in color (alkaline) and the butt yellow (acidic.) This meant that the bacteria were only able to ferment glucose. This was consistent with the initial finding from the MacConkey agar, that the bacteria were not lactose fermenters. The next step was to conduct an MIO test. After incubation it was determined that the bacteria were motile, which presented as turbidity in the tube. Ornithine decarboxylase was present in the medium, causing the bottom of the tube to turn purple. After the addition of Kovacs’ reagent, the surface turned bright red, indicating the presence of Indole. The next step was to perform a citrate test to differentiate between two types of bacteria, Clostridium difficile and Morganella morganii. The slant of Simmons citrate agar was streaked with the unknown bacteria. Following incubation, the color of the slant remained green indicating that the bacteria was not able to use citrate as a source of carbon and energy. The bacteria could then be identified as Morganella morganii. A urease test was used to confirm this result since Morganella morganii is known to produce urease. The urea agar slant with phenol red indicator was streaked with the bacteria. Following incubation, a color change was observed indicating the bacteria were able to split urea into ammonia and carbon dioxide, creating an alkaline

Bacteria are among the most abundant of all organisms on earth. Some species of bacteria is always present in every different environment the plant has to offer. For this to be possible, bacteria are all very different from one another. This lab aimed to identify a certain colony of bacteria, using a variety of tests at the disposal of scientists. The simplest method of narrowing down possibilities involves the use of a compound microscope to observe the general shape of the cells. The shapes of the bacteria can be Bacilli, Cocci, or Spirochete. This helps to further narrow the possibilities of what the bacterial species is.

Identification of bacteria is important for a verity of reasons, determining if a bacteria is normal flora, or potentially pathogenic as well as determining the bacterial source of an infection or outbreak. Identifying the bacteria is crucial when treating a bacterial infection because the correct antimicrobial or antibiotic must be used to successfully eliminate the infection and this cannot be done without the identity of the bacteria. Selecting the correct antibiotic is critical when dealing with an infection since not all antibiotics are equally effective against bacteria. Finding the identity of the bacteria causing the infection allows the doctor to prescribe the appropriate antibiotic. Unfortunately looking at only cell or colony morphology cannot lead to a conclusive result because there are many similarities in colony and cell morphology even among the eight bacteria used in this experiment.

The selectivity for halophiles refers to a bacterium’s ability to grow in a salt environment. The media differentiated between mannitol fermenters and non-fermenters. The yellow agar meant that the bacterium was a fermenter, whereas no color change meant that the bacterium was not a fermenter. In Table 1, the test observed growth of colonies and a pink agar. The growth indicated that the bacterium represented a halophilic nature, while the pink agar indicated no fermentation of mannitol. Research discovered that E. coli had no growth of colonies and no change in media. Therefore, E. coli was ruled out. Also, B. megaterium and E. faecalis were discovered to have yellow medias from being able to ferment mannitol. However, in this lab, the unknown bacterium did not ferment mannitol. As a result, all the potential bacteria did not fit the expected results, so this test did not work. In the end, category IV tests did not represent helpful information that would help identify the unknown bacterium, since the bacterium indicated different observations compared to expected observations for eosin methylene blue agar and mannitol salts agar. A possible source of error of these two tests could have been that the bacterium was contaminated due to improper inoculation techniques, such as not using a loop that was completely