Streak Plate Method (M) Flashcards
What is the purpose of streaking in microbiology?
It is a technique used to isolate a pure strain from a single species of microorganism (often bacteria)
Who first developed the dilution or isolation by streaking method?
Loeffler and Gaffky
Where did Loeffler and Gaffky first developed the dilution and isolation by streaking method?
In Koch’s lab
What is involved in the dilution or isolation by streaking method?
These involves the dilution of bacteria by systematically streaking them over the exterior of the agar in a Petri dish to obtain isolated colonies w/c will then grow into the # of cells or isolated colonies
The decrease of bacteria should show that colonies are sufficiently what?
Spread apart to effect the separation of the diff types of microbes
What is used for streaking?
A sterile tool such as cotton swab or commonly an inoculation (or inoculating) loop
What is commonly used for streaking?
Inoculating loop
What are the importance provided by aseptic techniques when it comes to streaking?
1) These techniques are used to maintain microbiological cultures
2) To prevent contamination of the growth medium
What can be used to flame the inoculating loop?
1) Bunsen burner
2) Laboratory incinerator
3) Alcohol lamp
What are the different methods of streaking?
1) T- Streak
2) Three - Phase Streak Technique
3) Zig-Zag Streak
4) Quadrant Streak Plate Method
5) Other Methods of Streak
What is the process (or steps) of T - streak?
1) Flame inoculating loop
2) Get the inoculum
3) Rotate the plate in a counter clockwise direction (for right handed professionals) and begin streaking in Area 1
4) Flame the inoculating loop
5) Streak at Area 2
6) Flame the inoculating loop
7) Streak at Area 3
Why is T - streak named as it is?
Because the plate is divided into 3 areas via letter “T”
What is the process (or steps) of Three-Phase streak technique?
1) Sterile loop with sample
2) Using a sterile loop, streak the sx across the surface at the top of the plate in a continuous motion using thin, closely placed lines that do not cross one another
3) Flame and cool loop
4) Turn the agar plate 90 deg, then crossing the first sector only once or twice, streak in a continuous motion using thin, closely placed lines that do not cross one another
5) Flame and cool loop
6) Again, turn the agar plate 90 deg, then crossing the second sector only once or twice, streak in a continuous motion using thin, closely placed lines that do not cross one another
7) Sterilize loop
What must be strictly done before and after streaking?
Before streaking: the loop must be sterilized w/ the sx (the loop must be sterilized first before getting the sx)
After (each) streaking: the inoculating loop must be flamed and cooled
What is the process (or steps) in quadrant streak plate method?
1) Deposit culture in a line across area in 1st quadrant, then streak 1st quadrant
2) Flame loop, make 6 - 8 directional streaks (2nd quadrant)
3) Flame loop, make 6 - 8 directional streaks (3rd quadrant)
4) Make zig-zag streaks w/out flaming loop
* the angle or height of the inoculating loop should not be too vertical or too flat, it should only be just right
What are the other methods of streak (or streaking)?
1) Continuous streak
2) Radiant streak
What are the significances of streak plate method?
1) The streak plate technique is the most popular method for isolating sp bacteria from a sx containing a mixture of microorganisms
2) Streak plate technique is used to grow bacteria on a growth media surface so that individual bacterial colonies are isolated and sampled
3) Sxs can then be taken from the resulting isolated colonies and a microbiological culture can be grown on a new plate so that the organism can be identified, studied, or tested
4) When the bacteria are streaked and isolated, the causative agent of a bacterial disease can be identified
What is the most popular method for isolating bacteria from a sx containing a mixture of microorganisms?
The streak plate technique
Streak plate technique is used to grow bacteria on a what?
On a growth media surface
Why is streak plate technique used to grow bacteria on a growth media surface?
So that individual bacterial colonies are isolated and sampled
Where does the sx come from for making a microbiological culture grown on a new plate so that the organism can be identified, studied, or testing?
Sxs can be taken from the resulting isolated colonies
What is the result when the bacteria are streaked and isolated?
The causative agent of a bacterial disease can be identified
What is the process (or steps) of streak plate method?
1) Flame to sterilize inoculation loop
2) Collect bacteria onto loop
3) Inoculate plate
4) Inoculation procedure (flame loop bet streaks)
5) Formation of discrete colonies
