Cultural Characteristics of Bacteria and viruses Flashcards
What is the purpose of growth media in microbiology?
To study and grow microorganisms under controlled laboratory conditions.
Culture
A nutrient material prepared for the growth of microorganism in a laboratory
Inoculum
Microbes that are introduced into a culture medium to initiate growth
Properties of Agar
-Can only be degraded by a few microbes, it remains solid
-Liquefies at 100°C
-Usuall containd in petri dishes or test tubes
-Test tube are called slants
Slants
When the tube is held at an angle so that a large surface area for growth is available
What are the three main types of media based on consistency?
Liquid, semi-solid, and solid media.
What is broth in the context of liquid media?
A transparent fluid made from meat extract or peptone used to culture bacteria.
Name an advantage of liquid media.
Allows the growth of bacteria in large volumes, useful for preparing vaccines.
What are the advantages of solid media?
Allows study of colony morphology and helps isolate pure colonies.
What is simple media also known as?
Basal media.
What is complex media?
Media with added nutrients for special growth purposes.
What is synthetic media?
Media with a precisely defined chemical composition.
What is enriched media?
Provides nutrients and the environmental condition that favors the growth of particular microbes
Example of enrichment media?
Tetrathionate broth.
inhibit coliforms and allow typhoid paratyphoid bacilli to grow freely
What is selective media?
Suppresses the growth of unwanted bacteria and encourages the development of desired microbes
Example of selective media?
MacConkey agar.
Used to isolate & distinguish between Gram-negative enteric rods. MacConkey agar contains bile salts and crystal violet that inhibit Gram positive bacteria but allow the growth of Gram negative bacteria.
What is differential media?
Media that distinguishes between colonies of microbes on the same media
Example of differential media?
Blood Agar
Differentiates bacteria based on their ability to hemolyze (break down) red blood cells.
ex: Example: Streptococcus pyogenes
What are the six parameters to describe colony morphology?
Size, color, texture, form, elevation, and margin.
What is the purpose of the Indole test?
To evaluate the organism’s ability to split tryptophan into Indole.
This test is used to help distinguish between Enterobacteriaceae species.
What does a positive Indole test look like?
Bright red color at the interface of the reagent and broth.
What is the MR test used for?
To detect stable acid end-products from glucose fermentation.
Used to distinguish species of the family Enterobacteriaceae.
What color indicates a positive MR test?
Red.
What is the Voges-Proskauer (VP) test used for?
To detect neutral end-products like acetoin from glucose fermentation.
Used to distinguish species of the family Enterobacteriaceae
