Lab Report On Gram Staining
Day 1
Throughout the semester, I have learned multiple techniques for identifying bacteria. Learning how to gram stain, use specific media such as MacConkey agar, and test antibiotics to see which antibiotic would react best against a specific organism. All these techniques helped me prepare for the final lab, identification of an unknown bacterium. For the final lab, I received the organism “6A”. To start identifying this organism, I did a gram-stain to identify if the organism is gram positive or negative. I created two slides to ensure that I did the stain correctly with similar results. The gram-stain consists of creating a smear from the given plate and fixing it to the plate with methanol, then, dying the smear with crystal violet for …show more content…
The test for ornithine decarboxylation detects for enzymatic activity, specifically if dextrose is fermented causing a color change of the medium from purple to yellow. After this enzymatic activity, ornithine decarboxylase is activated causing the color of the agar to change back to purple, which shows a positive result while yellow would be a negative result. The MIO tube that had a stab inoculation of my organism resulted in a purple medium resulting in a positive test.
The indole production test is tested after incubation of the tube. To get the results, Kovac’s reagent must be added to the tube. Kovac’s reagent has the indicator p-dimethylamino-benzaldehyde which will produce a red ring on the surface of the agar resulting in a positive test. After incubation, I added Kovac’s reagent into the MIO tube which did not result in a color change, indicating a negative result for indole …show more content…
The methyl red test will indicate if the organism produces acidic or neutral end products by the fermentation of carbohydrates. After inoculation, methyl red is directly added to the broth, a positive result is a red coloring of the broth while a negative result shows no color change. After inoculation, I added methyl red to the tube to identify what type of end-products were produced. This addition of methyl red didn’t change the color of the broth which indicated neutral end-products by carbohydrate fermentation.
Day 3
After looking at these test results I concurred that the organism 6A is Pseudomonas aeruginosa. By looking at the table provided by Dr. Jackson, I could see that these test results of a positive ornithine decarboxylation, a negative indole production, a positive urea hydrolysis, and a negative methyl red test indicated this organism.
Test Ornithine Decarboxylation Indole Production Urea Hydrolysis Methyl Red Test
Result Positive result Negative result Positive result Negative
Throughout the semester, I have learned multiple techniques for identifying bacteria. Learning how to gram stain, use specific media such as MacConkey agar, and test antibiotics to see which antibiotic would react best against a specific organism. All these techniques helped me prepare for the final lab, identification of an unknown bacterium. For the final lab, I received the organism “6A”. To start identifying this organism, I did a gram-stain to identify if the organism is gram positive or negative. I created two slides to ensure that I did the stain correctly with similar results. The gram-stain consists of creating a smear from the given plate and fixing it to the plate with methanol, then, dying the smear with crystal violet for …show more content…
The test for ornithine decarboxylation detects for enzymatic activity, specifically if dextrose is fermented causing a color change of the medium from purple to yellow. After this enzymatic activity, ornithine decarboxylase is activated causing the color of the agar to change back to purple, which shows a positive result while yellow would be a negative result. The MIO tube that had a stab inoculation of my organism resulted in a purple medium resulting in a positive test.
The indole production test is tested after incubation of the tube. To get the results, Kovac’s reagent must be added to the tube. Kovac’s reagent has the indicator p-dimethylamino-benzaldehyde which will produce a red ring on the surface of the agar resulting in a positive test. After incubation, I added Kovac’s reagent into the MIO tube which did not result in a color change, indicating a negative result for indole …show more content…
The methyl red test will indicate if the organism produces acidic or neutral end products by the fermentation of carbohydrates. After inoculation, methyl red is directly added to the broth, a positive result is a red coloring of the broth while a negative result shows no color change. After inoculation, I added methyl red to the tube to identify what type of end-products were produced. This addition of methyl red didn’t change the color of the broth which indicated neutral end-products by carbohydrate fermentation.
Day 3
After looking at these test results I concurred that the organism 6A is Pseudomonas aeruginosa. By looking at the table provided by Dr. Jackson, I could see that these test results of a positive ornithine decarboxylation, a negative indole production, a positive urea hydrolysis, and a negative methyl red test indicated this organism.
Test Ornithine Decarboxylation Indole Production Urea Hydrolysis Methyl Red Test
Result Positive result Negative result Positive result Negative