Unknown Bacteria Lab Report

The two streak plates made from the mixture of unknown bacteria showed two different colony morphologies. Colonies of Bacteria A were translucent in color, circular in form, with entire margins and a smooth surface. Colonies of Bacteria B were cream colored, irregular in form, with undulate margins and an ambulate surface. Two different morphologies allowed Gram stains to be performed on each of the bacterium. Gram staining of Bacteria A revealed pink, rod-shaped cells signifying that the bacterium was Gram-negative and rod-shaped.

Essay Example on Unknown Bacteria Report

Next, an oxides test was performed to eliminate one or more of the bacterium choices. P. Organisms was eliminated as the identity of the bacterium when the oxides test results were negative. An EMBED plate of the bacteria was examined to identify whether the bacterium was S. Typhoid or E. Coli. The growth on the EMBED plate was shiny and metallic green, meaning that it was positive for lactose fermentation. S. Typhoid exhibits intermediate lactose fermentation with pink or purple growth on an EMBED plate, so it was eliminated as the possible identity of Bacteria A.

To confirm the identity of Bacteria A as E. Coli, an Underwrote test inoculated with Bacteria A was observed. The Bibcock confirmed the identity of Bacteria A as E. Coli. Gram staining of Bacteria B revealed purple, rod-shaped cells signifying that the bacterium was Gram-positive and rod-shaped. The shape of the bacterium eliminated Cisco-shaped S. Erasures and S. Epidermises as possibilities for the identity of Bacteria B.

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Next, an endoscope stain of the bacteria was examined to identify whether the bacterium produced spores or not.

The stain showed red ells with green spores, indicating that the bacterium did produce spores. The results of the endoscope stain confirmed the identity of Bacteria B as B. Subtitle. Table 1 lists all of the biochemical tests, their purpose and results. The results are also shown in flow chart form in Table 2. RESULTS Test Purpose Reagents Observations Results Gram Stain To determine the gram reaction of bacteria Crystal violet, Iodine, Alcohol, Seafaring Unknown A: pink rods Unknown B: Purple rods Unknown A: gram negative bacilli Unknown B: gram positive bacilli Oxides Test To determine the presence of oxides

Oxides paper Unknown A: yellow Unknown A: negative for oxides Lactose Fermentation Test To determine if bacteria ferments lactose EMBED plate Unknown A: shiny, green, metallic colonies Unknown A: positive for lactose fermentation Endoscope Stain To determine if bacteria produces endoscopes Malachite green, Steam, Seafaring Unknown B: red cells with green spores Unknown B: Positive for producing endoscopes Underwrote To identify gram negative interchangeable Unknown A: code 24160 Unknown A: E. Coli Table 1: Biochemical tests performed on Unknown A and Unknown B.