Unknown Bacteria Report

The objective of this activity was to use the knowledge that we obtained throughout the semester, with the goal to correctly identify two unknown bacteria.
Organism number thirteen is Escherichia coli. On the first day, I conducted a gram stain and noticed that the bacteria were pink, meaning that the bacteria are gram negative. I also recognized that the bacteria were rod shaped therefore they were bacillus. I also noticed that the arrangement appeared to be single celled. I also put the bacteria on a streak plate. On the second day, I did another gram stain and the bacteria were again pink and bacillus or rod shaped. I also observed the bacteria on a nutrient agar plate and noticed that the bacteria were light white almost clear color bacteria. I took the bacteria that were growing on the nutrient agar plate and put the bacteria into a broth tube. …show more content…
On the third day, I put the bacteria that were in the broth tube on differential media. I chose to put the bacteria on EMB and Pseudo P plate, because I believed that the bacteria was either Escherichia coli or Pseudomonas aeruginosa, due to the shape and the fact that the mystery bacteria was gram negative. I also did a gram stain and the bacteria remained pink and bacillus or rod shaped. On the fourth day, I was able to observe the differential media. I noticed that on the Pseudo P plate the bacteria was a yellow color and on the EMB plate there was a small tint of metallic green color. Due to the metallic green tint on the EMB plate, the yellow pigment on the Pseudo P plate, as well as the bacillus shape, and being gram negative I concluded that the mystery bacteria number thirteen is indeed Escherichia coli. Therefore, I was able to rule out that my bacteria is not Pseudomonas aeruginosa, because on the Pseudo P plate the bacteria would have been a greenish blue color, which mine remained yellow. Also, on an EMB plate if it was Pseudomonas aeruginosa the bacteria would have been a dull purple, which my bacteria was a more vibrant purple in areas and had a small tint of metallic green. Organism letter R is Staphylococcus epidermidis. On the first day, I conducted a gram stain of this bacteria and noticed that it was a distinct purple color and was coccus, meaning the bacteria was gram positive and round shaped. The bacteria arrangement resembled that of grape clusters. I also put the bacteria on a streak plate. On the second day, I conducted another gram stain and the bacteria remained purple and coccus. I also observed the bacteria on a nutrient agar and found one single colony that was white. I took the bacteria that were growing on the nutrient agar plate and put the bacteria into a broth tube. On the third day, I put the bacteria on a differential media I chose to put the bacteria on a Mannitol Salt Agar (MSA) plate, because I believed that the bacteria was either Staphylococcus aureus or Staphylococcus epidermidis, because both bacteria are coccus and gram positive. I conducted a gram stain and the bacteria remained purple and coccus. On the fourth day, I was able to observe the differential media. I noticed that on the MSA the media remained pink. Due to the MSA remaining pink,