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STREAKING
CULTURE PLATES
IN BACTERIOLOGY
Dr.T.V.Rao MD
5/7/2016 Dr.T.V.Rao MD 1
Think Before Inoculation
• Before inoculation,
important information is
written on the bottom of
the plates, close to the ...
What is streaking
• The most common method of inoculating an agar plate is streaking.
•Streak plates
• 1.With this method,...
What is streaking
•The loop is then sterilised (by flaming) again and the
first streaks are then spread out themselves.
•....
The essential step in inoculating
culture plates
•There are several
essential precautions that
must be taken during
inocul...
Prompt action with Optimal
utility
•Operations must
not be started until
all requirements
are within
immediate reach
and m...
Expose the inoculum in test tubes
and containers for minimalTime
• Inoculum is grown in test
tubes and must be open for
th...
The Neck ofTest tube containing
inoculum to be heated briefly
•On being opened, the
neck of a test tube or
bottle must be
...
Exposure to Environment should
limited to minimum
•During manipulations
involving a Petri dish,
exposure of the sterile
in...
Work with absolute sterility
• The parts of sterile pipettes
that will be put into cultures or
sterile vessels must not be...
Work Using a wire loop
• Wire loops are sterilised using red
heat in a Bunsen flame before and
after use.They must be heat...
Flaming procedure
• The flaming procedure is
designed to heat the end of
the loop gradually because
after use it will cont...
Handling of the Inoculating loop
• Position the
handle end of the
wire in the light
blue cone of the
flame.This is the
coo...
Perfect the art handling the
Inoculating loop
• Draw the rest of the
wire upwards slowly up
into the hottest region
of the...
Heat and cool the Loop
• Ensure the full
length of the wire
receives
adequate
heating. .
Allow to cool
then use
immediatel...
Handle the Inoculating loop
Do not put the
loop down or wave
it around..
Re-sterilise the
loop immediately
after use.
5/7/...
Be careful some times the Loop may not
contain inoculum must redraw the inoculum
• If a loop does not hold any
liquid the ...
Working with bacteria and yeast
Streak plate
•The loop is used for
preparing a streak plate.
This involves the
progressive...
5/7/2016 Dr.T.V.Rao MD 19
The aim of the procedure is to obtain
single isolated pure colonies
• Loosen the cap of the
bottle containing the
inoculum...
5/7/2016 Dr.T.V.Rao MD 21
Handling matters in getting the
right inoculum
Lift the bottle/test tube
containing the inoculum
with the left hand. .
Rem...
Handling loop and Inoculating the material
matters
•Insert the loop into
the culture broth
and withdraw. At
all times, hol...
Do not Practice the
way
5/7/2016 Dr.T.V.Rao MD 24
Practice for
Perfection• Replace the cap/cotton
wool plug on the
bottle/test tube using
the little finger. Place
bottle/te...
Practice , Practice best way to Perfection
• Hold the charged loop
parallel with the surface of
the agar; smear the
inocul...
Follow the Instructions for safe keeping
of Petri dish
• Remove the loop and
close the Petri dish.
. Flame the loop and
al...
Streak the Plates in a defined
Manner
• With the cooled loop
streak the plate from
area ‘ across the
surface of the agar i...
Streak the Plates in a defined
Manner
• Remove the loop and
close the Petri dish. .
Flame the loop and
allow to cool.Turn ...
Carry with further inoculations
•Remove the loop and close
the Petri dish. . Flame the
loop and allow to cool.Turn
the dis...
Complete the work Close the petri dish
• Remove the loop and
close the Petri dish.
Flame the loop.
. Seal and incubate the...
References
•Basic Practical Microbiology© 2006 Society for
General Microbiology ISBN 0 95368 383 4
•Google resources from ...
•Program Created by Dr.T.V.Rao MD for the benefit of
Medical Microbiologists for learning basic principles in
inoculating ...
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Streaking culture plates in bacteriology

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Streaking culture plates in bacteriology by Dr.T.V.Rao MD

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Streaking culture plates in bacteriology

  1. 1. STREAKING CULTURE PLATES IN BACTERIOLOGY Dr.T.V.Rao MD 5/7/2016 Dr.T.V.Rao MD 1
  2. 2. Think Before Inoculation • Before inoculation, important information is written on the bottom of the plates, close to the rim • 1date of inoculation • 2.temperature of incubation • 3.duration of incubation • 4.microorganism inoculated 5/7/2016 Dr.T.V.Rao MD 2
  3. 3. What is streaking • The most common method of inoculating an agar plate is streaking. •Streak plates • 1.With this method, a small amount of sample is placed on the side of the agar plate (either with a swab, or as a drop from an inoculating loop if the sample is a liquid). • 2.A sterile loop (flamed until red hot, then cooled by touching the agar away from the inoculated sample) is then used to spread the bacteria out in one direction from the initial site of inoculation.This is done by moving the loop from side to side, passing through the initial site 5/7/2016 Dr.T.V.Rao MD 3
  4. 4. What is streaking •The loop is then sterilised (by flaming) again and the first streaks are then spread out themselves. •.This is repeated 2-3 times, moving around the agar plate. •What should happen is that single bacterial cells get isolated by the streaking, and when the plate is incubated, forming discrete colonies that will have started from just one bacterium each. 5/7/2016 Dr.T.V.Rao MD 4
  5. 5. The essential step in inoculating culture plates •There are several essential precautions that must be taken during inoculation procedures to control the opportunities for the contamination of cultures, people or the environment 5/7/2016 Dr.T.V.Rao MD 5
  6. 6. Prompt action with Optimal utility •Operations must not be started until all requirements are within immediate reach and must be completed as quickly as possible5/7/2016 Dr.T.V.Rao MD 6
  7. 7. Expose the inoculum in test tubes and containers for minimalTime • Inoculum is grown in test tubes and must be open for the minimum amount of time possible and while they are open all work must be done close to the Bunsen burner flame where air currents are drawn upwards. 5/7/2016 Dr.T.V.Rao MD 7
  8. 8. The Neck ofTest tube containing inoculum to be heated briefly •On being opened, the neck of a test tube or bottle must be immediately warmed by flaming so that any air movement is outwards and the vessel held as near as possible to the horizontal 5/7/2016 Dr.T.V.Rao MD 8
  9. 9. Exposure to Environment should limited to minimum •During manipulations involving a Petri dish, exposure of the sterile inner surfaces to contamination from the air must be limited to the absolute minimum5/7/2016 Dr.T.V.Rao MD 9
  10. 10. Work with absolute sterility • The parts of sterile pipettes that will be put into cultures or sterile vessels must not be touched or allowed to come in contact with other non-sterile surfaces, e.g. clothing, the surface of the working area, the outside of test tubes/bottles 5/7/2016 Dr.T.V.Rao MD 10
  11. 11. Work Using a wire loop • Wire loops are sterilised using red heat in a Bunsen flame before and after use.They must be heated to red hot to make sure that any contaminating bacterial spores are destroyed.The handle of the wire loop is held close to the top, as you would a pen, at an angle that is almost vertical.This leaves the little finger free to take hold of the cotton wool plug/screw cap of a test tube/bottle 5/7/2016 Dr.T.V.Rao MD 11
  12. 12. Flaming procedure • The flaming procedure is designed to heat the end of the loop gradually because after use it will contain culture, which may ‘splutter’ on rapid heating with the possibility of releasing small particles of culture and aerosol formation 5/7/2016 Dr.T.V.Rao MD 12
  13. 13. Handling of the Inoculating loop • Position the handle end of the wire in the light blue cone of the flame.This is the cool area of the flame 5/7/2016 Dr.T.V.Rao MD 13
  14. 14. Perfect the art handling the Inoculating loop • Draw the rest of the wire upwards slowly up into the hottest region of the flame, (immediately above the light blue cone). . Hold there until it is red hot.5/7/2016 Dr.T.V.Rao MD 14
  15. 15. Heat and cool the Loop • Ensure the full length of the wire receives adequate heating. . Allow to cool then use immediately. 5/7/2016 Dr.T.V.Rao MD 15
  16. 16. Handle the Inoculating loop Do not put the loop down or wave it around.. Re-sterilise the loop immediately after use. 5/7/2016 Dr.T.V.Rao MD 16
  17. 17. Be careful some times the Loop may not contain inoculum must redraw the inoculum • If a loop does not hold any liquid the loop has not made a complete circle.To correct the problem, first ensure that the loop has been sterilised and then reshape the loop with forceps. Do not use your fingers because of the possibility of puncturing the skin. 5/7/2016 Dr.T.V.Rao MD 17
  18. 18. Working with bacteria and yeast Streak plate •The loop is used for preparing a streak plate. This involves the progressive dilution of an inoculum of bacteria or yeast over the surface of solidified agar medium in a Petri dish in such a way that colonies grow well separated from each other.5/7/2016 Dr.T.V.Rao MD 18
  19. 19. 5/7/2016 Dr.T.V.Rao MD 19
  20. 20. The aim of the procedure is to obtain single isolated pure colonies • Loosen the cap of the bottle containing the inoculum. Hold the loop in the right hand. . Flame the loop and allow to cool. 5/7/2016 Dr.T.V.Rao MD 20
  21. 21. 5/7/2016 Dr.T.V.Rao MD 21
  22. 22. Handling matters in getting the right inoculum Lift the bottle/test tube containing the inoculum with the left hand. . Remove the cap/cotton wool plug of the bottle/test tube with the little finger of the right hand. . Flame the neck of the bottle/test tube. 5/7/2016 Dr.T.V.Rao MD 22
  23. 23. Handling loop and Inoculating the material matters •Insert the loop into the culture broth and withdraw. At all times, hold the loop as still as possible. . Flame neck of the bottle/test tube. 5/7/2016 Dr.T.V.Rao MD 23
  24. 24. Do not Practice the way 5/7/2016 Dr.T.V.Rao MD 24
  25. 25. Practice for Perfection• Replace the cap/cotton wool plug on the bottle/test tube using the little finger. Place bottle/test tube on bench. . Partially lift the lid of the Petri dish containing the solid medium. 5/7/2016 Dr.T.V.Rao MD 25
  26. 26. Practice , Practice best way to Perfection • Hold the charged loop parallel with the surface of the agar; smear the inoculum backwards and forwards across a small area of the medium (see streaked area . 5/7/2016 Dr.T.V.Rao MD 26
  27. 27. Follow the Instructions for safe keeping of Petri dish • Remove the loop and close the Petri dish. . Flame the loop and allow it to cool. Turn the dish through 90° anticlockwise. 5/7/2016 Dr.T.V.Rao MD 27
  28. 28. Streak the Plates in a defined Manner • With the cooled loop streak the plate from area ‘ across the surface of the agar in three or four parallel lines . Make sure that a small amount of culture is carried over. 5/7/2016 Dr.T.V.Rao MD 28
  29. 29. Streak the Plates in a defined Manner • Remove the loop and close the Petri dish. . Flame the loop and allow to cool.Turn the dish through 90° anticlockwise again and streak from ’ across the surface of the agar in three or four parallel lines . 5/7/2016 Dr.T.V.Rao MD 29
  30. 30. Carry with further inoculations •Remove the loop and close the Petri dish. . Flame the loop and allow to cool.Turn the dish through 90°anticlockwise and streak loop across the surface of the agar from ‘ into the centre of the plate 5/7/2016 Dr.T.V.Rao MD 30
  31. 31. Complete the work Close the petri dish • Remove the loop and close the Petri dish. Flame the loop. . Seal and incubate the plate in an inverted position.There are alternative methods for preparing a streak. 5/7/2016 Dr.T.V.Rao MD 31
  32. 32. References •Basic Practical Microbiology© 2006 Society for General Microbiology ISBN 0 95368 383 4 •Google resources from images 5/7/2016 Dr.T.V.Rao MD 32
  33. 33. •Program Created by Dr.T.V.Rao MD for the benefit of Medical Microbiologists for learning basic principles in inoculating the culture plates, as a Mission for Universal education of skills in Microbiology •Email •doctortvrao@gmail.com 5/7/2016 Dr.T.V.Rao MD 33

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