MICRO Module 4 Flashcards
(58 cards)
What is the purpose of the motility test?
The motility test is used to determine the motility of an organism.
What type of media is used in the motility test?
The MTM media used is a semi-solid agar with a colorless indicator dye.
How is the motility test performed?
Dip a sterile inoculating needle into the bacteria using aseptic technique, then stab the media about two thirds of the way down into the MTM media.
What indicates bacterial growth in the motility test?
Bacterial growth is detected by the presence of red color produced when the dye is reduced by the bacteria.
What should be observed after incubating the inoculated tube?
Observe the media for bacterial growth; non-motile bacteria will show red dye only in the stab line, while motile bacteria will diffuse the dye.
How are the results of the motility test recorded?
Record the reaction for motility or non-motility based on the diffusion of the red dye.
What does a negative result in the motility test look like?
A negative result is seen when bacteria do not move along the line of inoculation, indicated by a sharp line.
What does a positive result in the motility test look like?
A positive result is seen when bacteria diffuse from the sharp line of inoculation, which can be partial or complete.
What is the purpose of the lactose fermentation test?
To determine if bacteria can ferment lactose into acidic end products.
What does the lactose fermentation broth contain?
Lactose sugar and a pH indicator.
What color change indicates a positive result in the lactose fermentation test?
The broth changes from salmon-pink to yellow.
What is the first step in the lactose fermentation test protocol?
Inoculate a tube of lactose broth with bacteria using a sterile inoculating loop.
What should be done after inoculating the lactose broth?
Incubate the inoculated tube until the next lab session.
How do you determine the result of the lactose fermentation test?
Observe the reaction for color change.
What does a negative result look like in the lactose fermentation test?
The lactose broth does not change color and remains salmon-pink.
What does a positive result look like in the lactose fermentation test?
The broth changes to a yellow color.
What does the Urease Test detect?
The Urease Test detects the ability of bacteria to produce the enzyme urease.
What happens when urease hydrolyzes urea?
Urease hydrolyzes urea to produce ammonia.
What is the visual indicator used in the Urease Test?
The phenol red indicator is used, which changes to hot pink in the presence of ammonia.
What is the first step in the Urease Test protocol?
Inoculate a tube of Urea slant with bacteria using a sterile inoculating loop.
What should be done after inoculating the Urea slant?
Incubate the inoculated tube until the next lab session.
How do you determine the result of the Urease Test?
Observe the reaction for color change.
What indicates a positive result in the Urease Test?
A positive result is indicated by the Urea slant changing to a hot pink color.
What indicates a negative result in the Urease Test?
A negative result is indicated when the Urea slant remains yellow.
