University of Oklahoma College of Medicine. Also, healthcare workers can help prevent the spread of disease by knowing how different types of bacteria are passed. This policy had an intervention period from April, 2007, to May, 2008. Observations made from the tests were then compared to a gram negative unknown chart in order to identify the bacteria. The first biochemical test performed was a negative Urea test which left two bacteria. The oxidase test was performed on unknown 122 gram positive, showed to be positive.
Test Observation Result Methyl Red Broth turned Red Produced acid from glucose metabolism Voges Proskauer V-P Broth turned Pink Produced acetyl methyl carbinol Casein Plate had clear zone Produced casease which hydrolyzed casein Maltose Media turned yellow Does ferment maltose Gram Stain Purple rods Gram Postive Table 3. It is commonly used to identify members of the genus Enterococcus E faecalis and E. Place a novobiocin disk lightly onto the surface. A positive catalase test removed E. Casein and animal tissue are used as sources of amino acids. Once the molecules are converted to pyruvate many products can be made all depending on the pH of the environment.
Once confirmed biochemical tests were done from an identification list to identify the specific type of bacterium. This chemical inhibits the growth of Gram-negatives. After performing Gram stains, a Gram negative rod was observed. Introduction: The purpose of this lab was to determine the identity of an unknown bacteria slant culture using a series of differential tests. In order to identify these bacteria, a series of different laboratory tests must be done.
A Gram stain was performed from an isolated colony and the slide showed only a gram negative rod bacterium. Bacteria, Enzyme, Gram staining 2042 Words 6 Pages this lab was to isolate and identify two unknown bacteria from a mixed culture provided to us by our instructor. Gram negative bacteria cell walls have a thin peptidoglycan layer, in which an ample amount of lipids cross throughout the peptidoglycan and cell membrane. The starch test was used to identify which bacterium can produce the enzyme amylase. Next the decolorizer washes the stains from gram negative while leaving the mordant on gram-positive. In order to identify this unknown the seven different types of biochemical tests will be conducted on this unknown bacterium to identify it out of 6 possible bacteria; Escherichia coli E.
This is a test commonly used when trying to identify Gram-negative enteric bacteria, all of which are glucose fermenters but only some of which produce gas. A positive urease bacteria will turn the broth pink in approximately 24 hours to 6 days for a rapid urease-positive organism and can take up to 8 days for a slow urease-positive organism. Since the isolation technique did not work, one mannitol salt agar plate was streaked with the initial unknown culture to allow the growth of only the Gram positive bacterium. This narrowed down the unknown to 5 possible answers: Escherichia coli, Klebesiella pneumoniae, Enterobacter aerogenes, Proteus vulgaris, and Pseudomonas aeruginesa. Proteus species are part of the Enterobacteriaceae family of gram-negative bacilli. This was Gram stained 1 using the method in the lab manual pg 67 and found an abundance of purple cocci with very few pink rod.
The recognition of these unknown bacterial cultures is achieved by the isolation and differentiation of the unknown culture based on certain biochemical characteristics, and metabolic pathways. Centers for Disease Control and Prevention, 17 Jan. Upon observation the isolation plate showed growth of two different colonies. Within the urea broth all of the essential nutrients that bacteria would need are provided by peptone and glucose and the potassium phosphate is used as a mild buffer that resists alkalinization due to peptone metabolism. This test is commonly used to distinguish between the b-hemolytic streptococci: Streptococcus agalactiae bacitracin resistant and Streptococcus pyogenes bacitracin sensitive. Based upon the results, both Gram-negative and Gram-positive bacteria were observed in the unknown mixed culture.
One way this benefits humans and animals is by producing vitamin K2 2. There were 34 isolated colonies present, all of which showed the same growth pattern. This study was done using the methods of sterile technique and biochemical tests that have been practiced throughout the semester in the microbiology laboratory. Sheep blood is commonly used, but some organisms require rabbit or bovine blood. All procedures were followed as stated in the course Lab Manual 1. Escherichia coli is indole positive.
Various tests were conducted on each the unknown bacterial cultures. The purpose of scientific writing is not to entertain, but to inform. Next iodine creates a mordant by combining with the crystal violet, holding it stronger near the gram-positive cells with the thicker cell wall. Spirit blue agar contains an emulsion of olive oil and spirit blue dye. In conclusion, it was found that the gram positive bacterium was indeed Staphylococcus aureus and the gram negative bacterium was Klebsiella pneumoniae. Lab Manual for General Microbiology. To further delineate a pure colony, Gram staining was completed.
Like any other enzyme in the intestines, E. The gelatin hydrolysis test was performed by stab-inoculating a tube of Nutrient Gelatin tube with an inoculating needle. To identify Strain B multiple tests were done to systematically narrow down the choices for its identity. The organism shown on the right is negative for starch hydrolysis. The second selective ingredient is sodium azide. The following Tables and Flowcharts give a guideline as to which tests were performed and there outcomes for both Gram Positive and Gram Negative bacteria. A simmons citrate and urea test were performed on the pure culture.