Bacterial Unknown Day 4 and 5-29

Bacterial Unknown Day 4 and 5-29 - Identification of...

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1 Identification of Bacteria: Unknowns Students should add 10-15 drops of each reagent directly to the test tubes for the MRVP tests. Students should be sure to vortex the media for each test after the reagents have been added and prior to reading the test results. For the MRVP tests : Methyl Red for the Methyl Red test. Barritt’s Reagents: α -Naphthol and then KOH for the Voges-Proskauer test Day#4: Hydrolysis Tests Materials: (per student) 1 Urea broth (5ml) (Ex. 5-15) TSB cultures of: 1 Tryptone broth (5ml) (Ex. 5-20) S. aureus 1 Spirit Blue Agar plate (25ml) (Ex. 5-19) E. coli 1 Milk Agar plate (25ml) (Ex. 5-16) E. tarda 1 Starch Agar plate (25ml) (Ex. 5-13) Students will be inoculating controls on the agar plates opposite their unknown as indicated in the figure below. Controls will not be inoculated for the Urea and Tryptone broths. All tube media will be incubated at 37 o C for 48 hours. All agar plates will be incubated at 37 o C for 24 hours. Positive Control Unknown Negative Control Hydrolysis Tests: Urea Hydrolysis: Tests for: the presence of urease which can hydrolyze urea into ammonia and CO 2 Reagent : - pH indicator : Phenol Red for detecting ammonia production; pH of media will rise as ammonia is produced; (red for pH >7 and yellow for pH <7) Results : - positive : red (fuschia) color change - negative : yellow (orange) color Tryptone Hydrolysis : Tests for: presence of tryptophanase which can hydrolyze tryptophan into indole and pyruvic
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Bacterial Unknown Day 4 and 5-29 - Identification of...

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