Unknown Lab Report
Purpose:
To identify an unknown bacterial specimen using basic laboratory technique and biochemical tests. The unknown bacteria will be one of the following: Enterococcus faecalis, Staphylococcus saprophyticus, Escherichia coli, Enterobacter aerogenes, Proteus vulgaris, Salmonella [I assume typhimurium], or Shigella [either flexneri or sonnei, we used both in our lab during the semester].
Procedure {and observations}:
Observe bacterial colony morphology. {Colonies are large, beige or cream-colored, with irregular borders.}
Prepare two slides for gram staining and viewing under a microscope. {Either my gram-stain slides were bad or the microscopes I chose for viewing were not good. No bacteria were found under the microscope.}
Prepare another gram stain of the unknown bacteria. {Gram-positive, coccus shaped bacteria were observed under the microscope. Also noted, the slide may have been inadvertently contaminated during the gram stain process by another person in the laboratory.} [I do think that the gram-stain result is surprising - the two gram-positive cocci species we've been given form medium-sized, round, uniformly colored colonies on TSA plates.
When I say the borders of the bacterial colonies are irregular, I mean that both the shape is irregular and the consistency of the borders is not like the center of the colony. I associate this type of appearance with rod-shaped bacteria in general, whether gram-positive or gram-negative.]
Perform catalase test. {Catalase test is positive.}
Inoculate test tubes prepared with the following mediums – Triple Sugar Iron agar slant (TSI slant), Bile Esculin Agar slant (BEA tube), a methyl-red Voges-Proskauer tube (MR-VP tube) and a Urease tube. Incubate the inoculated tubes, to be read at the following lab session.
Observe results of tests inoculated during the last session [Note: I used the wrong setting on my digital camera to take these pictures, so they are all blurry! Also, thinking
To identify an unknown bacterial specimen using basic laboratory technique and biochemical tests. The unknown bacteria will be one of the following: Enterococcus faecalis, Staphylococcus saprophyticus, Escherichia coli, Enterobacter aerogenes, Proteus vulgaris, Salmonella [I assume typhimurium], or Shigella [either flexneri or sonnei, we used both in our lab during the semester].
Procedure {and observations}:
Observe bacterial colony morphology. {Colonies are large, beige or cream-colored, with irregular borders.}
Prepare two slides for gram staining and viewing under a microscope. {Either my gram-stain slides were bad or the microscopes I chose for viewing were not good. No bacteria were found under the microscope.}
Prepare another gram stain of the unknown bacteria. {Gram-positive, coccus shaped bacteria were observed under the microscope. Also noted, the slide may have been inadvertently contaminated during the gram stain process by another person in the laboratory.} [I do think that the gram-stain result is surprising - the two gram-positive cocci species we've been given form medium-sized, round, uniformly colored colonies on TSA plates.
When I say the borders of the bacterial colonies are irregular, I mean that both the shape is irregular and the consistency of the borders is not like the center of the colony. I associate this type of appearance with rod-shaped bacteria in general, whether gram-positive or gram-negative.]
Perform catalase test. {Catalase test is positive.}
Inoculate test tubes prepared with the following mediums – Triple Sugar Iron agar slant (TSI slant), Bile Esculin Agar slant (BEA tube), a methyl-red Voges-Proskauer tube (MR-VP tube) and a Urease tube. Incubate the inoculated tubes, to be read at the following lab session.
Observe results of tests inoculated during the last session [Note: I used the wrong setting on my digital camera to take these pictures, so they are all blurry! Also, thinking