Question: Required Information Biochemical Testing: Triple Sugar Iron Agar (TSIA) Read The Exercise In Your Lab Manual And Complete The Exercises That Follow Triple Sugar Iron Agar (TSIA) Is A Solid Media In Slant Form Used To Determine Fermentation And Sulfur Reduction (hydrogen Sulfide Production Properties Of Bacteria. This Media Allows For Differentiation …
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Required information Biochemical Testing: Triple Sugar Iron Agar (TSIA) Read the exercise in your lab manual and complete the exercises that follow Triple Sugar Iron Agar (TSIA) is a solid media in slant form used to determine fermentation and sulfur reduction (hydrogen sulfide production properties of bacteria. This media allows for differentiation between monosaccharide and disaccharide fermenters due to the presence of glucose (monosaccharide), lactose (disaccharide) and sucrose (disaccharide) in the media. A property of glucose-only fermenting bacteria, called reversion, can be detected due to an extremely low concentration of glucose and a high concentration of sucrose and lactose. Reversion is the ability of a bacterium to switch or revert, its metabolism from one form to another in this case from fermentation to protein catabolism. In the TSIA, organisms only capable of fermenting glucose (monosaccharide) will quickly run out of the sugar (due to its low concentration) and “revert to protein catabolism. This will cause a shift in pH that can be detected by color changes in phenol red in the media. Sulfur reduction is determined by the presence of a black precipitate in the butt of the slant Bacteria capable of reducing sulfur use the enzymes thiosulfate reductase and/or cysteine desulfurose to reduce sulfur containing compounds and give off hydrogen sulfide (H2S) gas. An iron salt in the media reacts with the H2S gas and forms a black precipitate that is easily observed Inoculation of this media requires a stab-streak method in a slont using a needle. Be careful not to place too much bacteria on the upper portion of the slant as this may cause some results to be misinterpreted. The following video demonstrates the proper technique used to inoculate a TSIA slant and interpret results. Determining TSIA Results Read about recording and interpreting TSIA results and complete the questions that follow, The TSIA test is helpful in identification of gram-negative enteric bacteria. Results are recorded in a specific sequence, starting with the slant, then the butt of the tube and finally H2S results are recorded seperately. Acid results are recorded with an A and alkaline results are recorded with a K. For example, TS that is completely yellow after incubation would be recorded as Acid Acid H2S negative, or AA H2S () A TSI that is pink at the slant and yellow in the butt is recorded as Alkaline Acid H2S negative, or KIA H25 – Finally, a TS that is yellow at the slant and black in the butt is recorded as Acid Acid H2S positive, or AJA H2S 4 Review the pictures of the three TSI results below and answer the questions that follow. You may collapse and expand the report box as needed. Crnanirm 1 This question will be sent to your instructor for grading are recorded with a For example, a TS that is completely yellow after incubation would be recorded as Acid Acid H2S negative, or A/AH25 A TSI that is pink at the slant and yellow in the butt is recorded as Alkaline Acid H2S negative or KIA H256) Finally, a TS that is yellow at the slant and black in the butt is recorded on Acid Acid H2S positive, or A/AH25 Review the pictures of the three TSI results below and answer the questions that follow. You may collapse and expand the report box os needed Organism 1 Organism 2 Organism 3 Alle cationis Bergh 1. Organism 2 shows a color change to black in the butt of the slant. What does this color change indicate? Organism 3 All photos: McGrew Education Lise Burgess, photographer 1. Organism 2 shows a color change to black in the butt of the slant. What does this color change indicate? 2. How is the result for Organism 1 recorded and what does the result mean? 3. If you were to test Organism 3 using phenol red broths for glucose, lactose and sucrose, what would be the predicted results for each broth excluding gas production? 4. How would you know from the TSIA for organism 2 that it would be positive for glucose fermentation?
