Microbiology. Clinical Pathology. Microbiology. The study of microscopic organisms Clinical microbiology is the identification of these organisms that cause clinical illness. Laboratory Safety. Most microorganisms are potentially pathogenic DO NOT EAT OR DRINK IN LAB!
Media supports most bacterial pathogens
(The Primary Streak)
If you are right-handed, hold the plate in your left hand, and the inoculating loop in your right - as through you would a paint brush. If you are left-handed, use the opposite hands.
Touch your inoculating loop (sterile swab, or sterile stick as shown in the picture) to the material you want to spread.
Go back and forth a number of times in a small area of the Agar plate.
The goal is to spread your material completely over this inital area of the plate.
Step Two:(The Secondary Streak)Sterilize your inoculating loop, or use a fresh, sterile inoculating stick or swab. Make sure the loop is cool before your next streak. If you were to use the original loop, you will not be diluting the individual microbes you applied in the first streak.
Pick up the plate and rotate it 1/4 of a turn to your left (if right-handed), or to your right (if left handed).
Run the loop through the previous streak 2-3 times, then draw it along 1/3 of the remaining plate, as shown by the blue line in the image.
Step Three:(The Tertiary Streak)Rotate the plate another 1/4 turn and sterilize yourinoculating loop or take a fresh, sterile stick or swab. Again, make sure to cool your loop between streaks.
Run the loop through the previous, secondary streak 2-3 times, and draw the streak over a remaining 1/3 of the plate, as shown.
Step Four:(The Quarternary Streak)Rotate the plate another 1/4 turn and sterilize the inoculating loop. Again, cool the loop between streaks, or use a new sterile swab.
Run the loop through the previous tertiary streak 2 times and draw over the remaining free space in the plate, being careful not to contact the primary streak (yellow).
What is the basic shape of the colony? For example, circular, filamentous, etc.
What is the cross sectional shape of the colony? Turn the Petri dish on end.
What is the magnified shape of the edge of the colony?
How does the surface of the colony appear? For example, smooth, glistening, rough, dull (opposite of glistening), rugose (wrinkled), etc.
For example, transparent (clear), opaque, translucent (almost clear, but distorted vision, like looking through frosted glass), iridescent (changing colors in reflected light), etc.
For example, white, buff, red, purple, etc.
Examine number, types of bacteria