Archetype, Oxidase Test
The tube that contained my unknown material was tube number twenty. I did a gram stain, oxidase test, and used three different medias to narrow down and identify my unknown organism.
The first step I took in identifying was a gram stain. This gram stain would reveal whether my organism is gram positive or gram negative which would narrow my choices from fifteen options down to six. After completing the gram stain, my unknown was the color pink. This revealed my unknown as being gram negative. I also used the microscope to identify the morphology of the organism. I recognized the unknown to be staphylobacillus. Staphylobacillus means rod shaped cells in grape-like clusters. After establishing the morphology and gram stain I had six options for what my unknown was.
For my first selective and differential test I choose a media that would split my options in half. I choose a MAC plate for my first test. Using MAC was the best option because not only did it cut my options from six to three, depending on whether there was a positive or negative reaction, but it also was the easiest to read. For MAC each reaction was a clear good growth with a positive or negative reaction, whereas the other options had uncertainly because you had to distinguish variable reaction and weak reactions as well. After …show more content…
inoculating the MAC plate and letting the unknown grow my results where growth and a negative reaction. If an organism had a positive reaction it's supposed to turn pink on a MAC plate, but my did not. After MAC i was down to Pseudomonas Fluorescens, Proteus Vulgaris, and Providencia Stuartii. I then did an oxidase test, and my result was no blue color change, meaning it was negative. At this point I now had two options.
I decided to use a TSI tube as my next test. For TSI it tests the pH, gas, and H2S of the organism. My unknown results were K/A for the pH, negative one gas, and negative on H2S. (K/A,-,-). I read the slant of the tube and then the butt for identifying the pH. The slant was K and the butt was A. If there is gas present in your tube, there will be bubbles at the bottom of the tube. However, there was no bubbles or breaks, therefore negative on gas. H2S positive will show a black color near the bottom of your tube, my unkown had no black, so it was negative. This test really narrowed my unknown down to one organism, Proteus Stuartii.
The last test I did was in a SIM tube.
SIM tests for sulfur, indole, motility. For sulfur your organism should have a black color it its positive. My unknown had no black color, so negative for H2S. If the organism is positive for indole it's pink, and yellow for negative. My unknown stayed more of a yellow color, there wasn’t much pink. At most I would call it a weak positive. Motility tests for the turbidity, if its positive it’ll have a grey looking cloud near the top of the tube. My unknown had the grey cloud and tested positive. My assumption that my uknown was Providencia Stuartii is now verified. P.S fits every test result for MAC, SIM, TSI, and
oxidase.
The first step I took in identifying was a gram stain. This gram stain would reveal whether my organism is gram positive or gram negative which would narrow my choices from fifteen options down to six. After completing the gram stain, my unknown was the color pink. This revealed my unknown as being gram negative. I also used the microscope to identify the morphology of the organism. I recognized the unknown to be staphylobacillus. Staphylobacillus means rod shaped cells in grape-like clusters. After establishing the morphology and gram stain I had six options for what my unknown was.
For my first selective and differential test I choose a media that would split my options in half. I choose a MAC plate for my first test. Using MAC was the best option because not only did it cut my options from six to three, depending on whether there was a positive or negative reaction, but it also was the easiest to read. For MAC each reaction was a clear good growth with a positive or negative reaction, whereas the other options had uncertainly because you had to distinguish variable reaction and weak reactions as well. After …show more content…
inoculating the MAC plate and letting the unknown grow my results where growth and a negative reaction. If an organism had a positive reaction it's supposed to turn pink on a MAC plate, but my did not. After MAC i was down to Pseudomonas Fluorescens, Proteus Vulgaris, and Providencia Stuartii. I then did an oxidase test, and my result was no blue color change, meaning it was negative. At this point I now had two options.
I decided to use a TSI tube as my next test. For TSI it tests the pH, gas, and H2S of the organism. My unknown results were K/A for the pH, negative one gas, and negative on H2S. (K/A,-,-). I read the slant of the tube and then the butt for identifying the pH. The slant was K and the butt was A. If there is gas present in your tube, there will be bubbles at the bottom of the tube. However, there was no bubbles or breaks, therefore negative on gas. H2S positive will show a black color near the bottom of your tube, my unkown had no black, so it was negative. This test really narrowed my unknown down to one organism, Proteus Stuartii.
The last test I did was in a SIM tube.
SIM tests for sulfur, indole, motility. For sulfur your organism should have a black color it its positive. My unknown had no black color, so negative for H2S. If the organism is positive for indole it's pink, and yellow for negative. My unknown stayed more of a yellow color, there wasn’t much pink. At most I would call it a weak positive. Motility tests for the turbidity, if its positive it’ll have a grey looking cloud near the top of the tube. My unknown had the grey cloud and tested positive. My assumption that my uknown was Providencia Stuartii is now verified. P.S fits every test result for MAC, SIM, TSI, and
oxidase.