Purpose: TSI agar can be considered an initial step in the identification of the [blank_start]Enterobacteriaceae[blank_end]
Respuesta
Enterobacteriaceae
Salmonella typhi
Escherichia coli
Citrobacter diversus
Pregunta 2
Pregunta
Principle: for [blank_start]Indole Broth[blank_end]: tryptophan PRESENT in peptone is oxidized y certain bacteria to indole, skatole, and indoleacetic acid. Indole is detected in broth cultures of bacteria with an alcoholic p-dimethylaminobenzldehyde reagent. Indole reacts with the aldehyde to form a [blank_start]red[blank_end] product.
Respuesta
Indole Broth
Urea Agar
Voges-proskauer
Methyl red
red
black
yellow
gray
Pregunta 3
Pregunta
Key Ingredients: [blank_start]Indole broth[blank_end]: Tryptophan (1% broth), Kovac's reagent or Ehrlich's reagent, Xylene or chloroform for extraction if using Ehrlich's reagent
Respuesta
Indole broth
Methyl Red
Phenylalanine
LIA
Pregunta 4
Pregunta
Indole Broth Reactions:
Negative Reaction: [blank_start]No[blank_end] color development
Positive Reaction: [blank_start]red[blank_end] ring at the interfacec of reagent and broth)
Variable reaction: [blank_start]Orange[blank_end] color, indicates production of aktole, a methylated intermediate that may be a precursor to indole production
Respuesta
No
Red
Dark
Yellow
red
yellow
no
brown
Orange
Red
Black
Purple
Pregunta 5
Pregunta
Principle: Urea Hydrolysis (Christensen's Agar): Many organisms possess the enzyme urease which can hydrolyze urea with the release of ammonia and carbon dioxide which acts to increase the pH of the medium and turn the indicator phenol red from pale [blank_start]orange[blank_end] to dark [blank_start]fuchsia pink[blank_end]
Respuesta
orange
fuchsia pink
violet purple
green
fuchsia pink
orange
violet purple
green
Pregunta 6
Pregunta
Key Ingredients: Urea Agar
Urea Agar ([blank_start]christensen's Base[blank_end])
pH indicator = [blank_start]phenol red[blank_end]
Respuesta
christensen's Base
methyl red
spot indole broth
citrate
phenol red
methyl red
gelatin
API 20E strip
Pregunta 7
Pregunta
Interpretation: urea hydrolysis
A strong positive hydrolysis test: entire agar, slant and butt, turning [blank_start]deep pink[blank_end] after overnight incubation.
A moderate positive test: [blank_start]pink[blank_end] slant at 24 hours, with the intensity of the color increasing with extended incubation
A negative test: no change from pale [blank_start]orange[blank_end] color of the slant