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Unknown Bacteria Lab Report- Microbio
Course: General Microbiology (BIOL 455 )
28 Documents
Students shared 28 documents in this course
University: Kansas State University
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Unknown Bacteria Lab Report
Intro
Clinical laboratories need be able to test and identify any dangers related to the bacteria.
It is important to inform physicians of the identification characteristics of the bacteria in order
for the physician to start the appropriate treatment as soon as possible. In the case of an outbreak,
identification of characteristics or even the specific type of the bacteria gives physicians the
ability to source, control, and prevent the recurrence of the disease. Many different tests are
available to be used to identify the species of bacteria including, but not limited to, specific stain
techniques, colony morphology, enzymatic tests, and biochemical tests (Baron, 1996, Reller et
al., 2001). The purpose of this lab was to use different techniques to identify two unknown
species of bacteria, one being gram-negative and the other gram positive.
Methods
The gram stain was used to indicate whether each bacterium was gram-positive or gram-
negative. It was also used to identify morphology and grouping of the species.
The citrate utilization test indicates the use of citrate as a carbon source. If the citrate is
being utilized, basic conditions are produced. The medium will turn blue in basic conditions, pH
7.6 or greater. Acidic conditions, pH below 6.9, turns the medium green.
The EMB plate is a differential and selective medium. It does not allow gram positive
bacteria to grow and indicates lactose fermentation by the color of the colony. A green color
indicates vigorous fermentation. A pink/purple color indicates slow-moderate fermentation. No
color indicates no fermentation in the colony.
The urease test indicates the degradation of urea. A change in the color to red indicates
urea degradation. A negative result remains a yellow-orange color.