Lab 2 - Aseptic Technique

Question 1

why is aseptic technique a very important microbiological technique?

Answer 1

because it is used to prevent contamination (presence of unwanted microbes) of source cultures and inoculated media

Question 2

what are sources of contamination?

Answer 2

air, lab sources, our bodies

Question 3

why is the aseptic technique important in hosptials?

Answer 3

important to prevent HAIs (hospital acquired infections)

Question 4

what is the BIGGEST source of contamination?

Answer 4

the air which carry endospores, fungal spores, and aerosolized micorbes

Question 5

what are endospores?

Answer 5

dormant hardy structures formed by some bacteria like Bacillus and Clostridium, which are the hardest to kill

Question 6

what is the rain of microbes?

Answer 6

when these microbes are constantly moving around on air current and settling down on surfaces

Question 7

does our immune system usually protect us from the rain of microbes?

Answer 7

yes

Question 8

why don’t we want contamination?

Answer 8

because we usually only study one organism at a time, known as a pure culture

Question 9

in a lab, growth media, glassware, plasticware, etc are made sterile using what device?

Answer 9

an autoclave, which uses moist heat (steam) under pressure (121 degrees Celsius, 15 psi) to kill vegetative (growing) cells, viruses, and endospores

Question 10

what is sterile?

Answer 10

devoid of any living organisms

Question 11

what are the steps of the aseptic technique procedure?

Answer 11

1. Hold the inoculating loop in the dominant hand and the culture tube in the other hand
2. Flame the loop to sterilize it (red hot)
3. Open the culture tube with the pinky and ring finger, but keep it slanted to avoid contamination from the air
4. Flame the lip of the tube to sterilize it
5. Rest the loop inside the tube to cool it for 25-30 seconds
6. Gather a loopful of culture and remove it from the tube
7. Flame the lip of the tube again and re-cap it
8. Open the media tube, but keep it slanted to avoid contamination from the air
9. Flame the lip of the tube to sterilize it
10. Inoculate the medium with the loopful of culture
11. Flame the lip of the tube again and re-cap it
12. Flame the inoculating loop to sterilize it

Question 12

T/F: The medium can be in a tube, on a plate, or a slide

Answer 12

True

Question 13

What commonly encountered microorganisms are the hardest to kill?

Answer 13

Endospores

Question 14

Why do we normally incubate culture plates with the lid down and the base up? AKA, why are culture plates incubated upside down?

Answer 14

to lessen contamination risks from airborne particles landing on them and to prevent the accumulation of water condensation that could disturb or compromise a culture