Unknown Lab Report 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.

Next I performed a KOH test to further confirm that my organism was a Gram-negative species. For the KOH test, I added 3 drops of 10% potassium hydroxide (KOH) to a small drop of distilled water onto a clean microscope slide, transferred a visible clump of organism to the KOH solution using my inoculating loop. I than mixed the cells into the solution using small, circular motions for 60 seconds and then lifted up the loop to look for what appears to be a “stringing” affect which means it’s confirmed that it is gram- negative species. Next, I created a streak plate using nutrient agar so that I could see pure culture of my organism. I aseptically obtained a loop full of my organism and gently inoculated one quarter of the nutrient agar plate by running the loop back and forth across the surface. I then flame sterilized the inoculating loop, allowing it to cool for 10 seconds, and then streaked the organism from quadrant I into quadrant II using a zigzag motion technique. I repeated those steps streaking from quadrant II to quadrant III and then streaking from quadrant III to quadrant IV. Once completed, I put the streak plate in the incubator at 37° for 24-48 hours. 48 hours later, I check my streak plate and it had a lot of growth on it. I was able to determine that the organism was definitely an off white color, opaque. The IV quadrant was the quadrant that best

This experiment was conducted to find the genus and species of an unknown bacteria prescribed by the lab teacher, which was unknown bacteria GA3 in my case. Identification of unknown bacteria techniques are used on an every day basis to figure out what type of bacteria it is and to find the best method of how to treat a patient with this bacteria (1). All five “I’s” of Microbiology were used in the testing for the unknown culture. Inoculation was used several times to put the unknown culture into agar plates or into biochemical test tubes. After Inoculation of these tubes or plates, they always were placed into the incubator for further growth and development. Isolation was used to make sure we got the correct bacteria we were testing for. After each further isolation, we gram stained the culture and inspected the culture under a microscope to further help in the identification process of the unknown bacteria. Multiple tests were done on the unknown culture to make sure we were confident in what kind of bacteria the unknown was.

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

Specimens may contain several species of organisms and therefore primary isolation allows the identification of specific bacteria to be accurate.7 By isolating the organism in nutrient agar, two separate colonies of bacteria were identified. Unknown microorganism one had a red pigment called prodigiosin produced by secondary metabolic activities of some microorganisms at temperatures lower then 37℃.8 This compared to microorganism two which had a cream/ light blue pigment called pyocyanin, a toxin produced and secreted by the organism clearly exhibits that two individual organisms were present.9 Due to the red pigment of microorganism one all bacteria except Pseudoalteromonas rubra, Serratia marcescens, Vibrio ruber, and Hahella chejuensis can be excluded.8 The light blue pigment on the second organism can exclude all bacteria except Pseudomonas aeruginosa.9

A highly conserved gene will be used to identify a prokaryotic species isolated from the body. Fundamental lab techniques will be also explored and utilized, such as amplifying using PCR, cloning, and transforming the gene into a host cell. DNA electrophoresis and specific substrate plating will serve as analysis check points. The final product will be sequenced and compared to similar species to observe phylogenetic relationships.

The mannitol salt agar plate is used in the determination of microorganisms of the Staphylococcus genus. Within

On the first day of testing, a gram stain test, a KOH test, a catalase test, and an oxidase test were completed. The gram stain test indicated that the unknown species is a gram positive rod, and the bacteria showed no strings during the KOH test confirming that the species is gram positive. From these two tests, the unknown was concluded to be in the family Bacillicae. The bacteria remained yellow on the cotton swab even after the oxidase reagent was dropped onto the swab showing that the bacteria is oxidase negative. For the second day of testing, the bacteria were inoculated on an SBA plate, and the analysis of this plate was difficult. The result of the SBA plate was difficult to discern, and it was unclear if the bacteria completed beta hemolysis or alpha hemolysis. Therefore, an additional SBA test needed to be completed, and with this second test it was more obvious that the SBA plate underwent alpha hemolysis. The SBA result showing negative beta hemolysis, along with the negative result from the oxidase test, indicated that Bacillus cereus was not the identity of the unknown. At the same time that the SBA hemolysis test was undergone, the inoculation of an MSA plate at 37 degrees for 24 hours was also completed. There was yellow growth on the MSA plate indicating that it could grow at 7.5% NaCl and ferment mannitol.

The Gram-Stain was performed as the basis for testing and identification, as Gram-Stains are a primary test for identifying bacteria. Based on the result of the Gram-Stain, several more tests may be carried out to identify the bacteria. In this experiment, the initial Gram-Stain had no result, as there were no bacteria that could be seen in the microscope. This could be due to not collecting enough of the organism on the slide before beginning the Gram-Stain. The T-Streak was conducted in order to both be able to observe and conclude morphology of the organism as well as have an incubated culture to conduct other tests from. The results of the T-Streak showed that the organism was round, smooth, and flat. After the T-Streak was done another Gram-Stain was conducted in order to identify status of the bacteria. Using the T-Streak culture give more culture to work with and guarantees that an adequate amount of culture is put on the Gram-Stain slide. The Gram-Stain showed that the bacteria was Gram-Positive eliminating Groups VI-X on the flow chart. The positive result indicated that the bacteria have a thick cell wall composed primarily of peptidoglycan. When viewed under the microscope, the bacteria had a purple ring around them, but were slightly pink mostly likely due to over decolorization, and were thus able to be classified as Gram-Positive. They were in the form of irregular

Identifying bacteria species is essential in both the clinical and research field. Many times, diagnosis and treatments highly rely on correctly pin pointing the pathogen present is a sample. On the other hand, quality control in the lab of food and other products also relies on bacteria characterization (Carson, 76). Identification of bacteria allows predicting causes of diseases and determines pathogenicity of bacteria. In this experiment, three unknown bacteria will be identified from a mixed culture that contains one-gram positive, one-gram negative paracolon, and one-gram negative coliform. The paracolon bacteria are those those that cannot ferment lactose, and coliform are those

Mahan, C.R. Lehman, D.C. and Manuselis, G. (2014). Textbook of Diagnostic Microbiology. 5ed. Elesevier. UK.

In the unknown lab we had to find out what bacterium we had through a series of tests that we had previously done as a class. The

Organism one demonstrated irregular, flat, wavy, medium sized and cream coloured colony morphology when viewed on agar plate, however limited conclusive data can be obtained from these observations alone. In order to provide further information for diagnosis, additional culturing was conducted on a range of selective and differential media types including Horse Blood, MacConkey, Mannitol Salt and Brilliant chromogenic UTI agar’s. This demonstrated the organism was non-haemolytic, lactose fermenting, as evident through a red colony formation on the MacConkey agar, and unable to survive in high salt concentrations, as indicated through the lack of growth on Mannitol Salt agar. The

Detecting bacteria is a rapidly expanding field of research, producing innovative and effective ways of overcoming a variety of existing limitations. Current laboratory based bacterial detection and identification techniques often require long procedures, provide low sensitivity and specificity as well as slow turnaround times. These conventional techniques include microscopy, culturing bacteria, polymerase chain reactions (PCR) and biochemical assays.

Bacteria biochemical testing can determine the types and numbers in terms of colony forming units of bacteria present in a sample of different chemical. The testing could be focused on a specific type of bacteria, medical bacteria or a broad range of environmental bacteria. Since bacteria are present in virtually any environment, it’s important to be clear why the