Unknown Bacteria Report

My unknown bacterial species is a gram-negative, single bacillus bacterium.

The overall bacterial shape of the colony is circular, with a convex elevation, moist

surface texture, and an opaque color. It also has an entire margin, meaning it has

smooth, with no irregular edges.

One of the most significant tests I have to do to identify my unknown bacteria

is the gram stain experiment. The experiment allowed me to distinguish my

unknown bacteria if it is a gram-positive or gram-negative. During this experiment, I

did a heat-fixed smear of Staphylococcus epidermidis together with Escherichia coli

on one side of the slide and my unknown bacteria on the other. I covered the smear

with crystal violet for 1 minute then gently rinse …show more content…
Subsequently, I used safranin to counterstain for about

1 minute then rinsed with distilled water. I gently blot dry when it was done. I

observed the slide under oil immersion and came to the conclusion that my

unknown bacteria is a gram-negative due to its bright pink color. With this

experiment, I have eliminated all the possibilities that my unknown is a gram-

positive bacteria and now I am left with eight gram-negative possibilities for my

unknown.

The next experiment I did is the Oxidase Test. This test is used to determine whether the bacteria contains the respiratory enzyme cytochrome c oxidase. During this experiment, I used a plastic loop to transfer an ample amount of the bacterial control, Pseudomonas, in a paper saturated with reagent next to a small amount of

my unknown bacteria in the same paper. Never use a metal loop because it will give

you a false positive result. Another person in my group did the Escherichia …show more content…
This test will determine whether my unknown is Escherichia coli or Morganella morganii. The Urea Hydrolysis Test is used to differentiate other organisms based on their ability to hydrolyze urea with the enzyme urease to form ammonia. A positive result for urea hydrolysis will turn the slant agar into a bright pink color, and a negative result will stay orange or yellow color. Using a sterile loop, I heavily inoculated my unknown and streaking back and forth over the surface of the urea slant. Then I left it in the 37*C incubator for a few days and wait for the result. After a few days of incubation, my unknown turned the slant to a bright pink color, which is a positive result for urea hydrolysis. With this result, I have eliminated Escherichia coli as my possibility for my unknown because E. coli is negative in urea hydrolysis according to the data. With the help of these experiments and my peers, I subsequently eliminated the possibilities of my unknown one at a time, and I have concluded that my unknown bacterium is Morganella

Show More