What are the different qualities we look at for bacterial colony morphology?
- form or shape
How do we grow bacteria?
bacteria can be isolated and grown on or in either solid media or liquid media
What are the two different types of media?
How to we place bacteria on agar plate?
"streak out" the bacteria onto the agar
What is a pure culture?
agar plate or broth tube contains only one type of bacteria all descending from a common ancestor
What is a mixed culture?
agar plate or broth tube contains more than one type of bacteria
Can a mixed culture become a pure culture?
yes, you can transfer cells from a single pure colony to begin a pure culture on another agar plate or in a broth tube
How do we classify form or shape of bacterial colonies?
How do we classify elevation of bacterial colonies?
How do we classify margins of bacterial colonies?
root-like, branched like roots
raised in the center (like a belly button)
What influences bacterial colony color?
- nutrient supply
What can we combine colony color with when we are describing it?
optical properties - opaque, translucent, shiny, or dull
What growth patterns do we look for in broth?
- cloudiness (uniform fine turbidity)
- flocculent (clumps)
- broth surface growth
What do we have to do with the tube of broth to see the surface growth?
gently tilt the tube
What characteristics do we note about the broth surface growth?
How do we test for aerotolerance?
stab inoculation of bacteria into the bottom of an agar tube and see where the bacteria grows
What is obligate (strict) aerobes?
growth only on the surface
What is obligate anaerobes?
growth only in lower tube, away from the surface
What is facultative anaerobes?
What is microaerophiles?
growth just below the surface
Once we have identified size, shape, arrangement, structure, and gross appearance of the bacterial colony, what are the next steps?
- gram stain
- enriched media
- differential media
- selective media
- biochemical testing