Principle:
The
identification of bacteria is a careful and systematic process that uses many
different techniques to narrow down the types of bacteria that are present in
an unknown bacterial culture. It produces benefits for
many aspects of the research of microorganisms
and helps physicians correctly treat patients. Multiple
tests were performed to provide the fermentation
abilities, presence of certain enzymes, and
certain biochemical reactions. Qualitative observations were made
on the tests, which were compared to unknown bacteria
identification key to aid with the
identification process.
Various
steps involved in the identification of unknown bacteria are:Isolation:
The
importance of this step is to isolate pure colonies of bacteria. The streak
plate is a qualitative isolation method; quadrant streaking is mostly done to
obtain pure colonies. The inoculation of the culture is made on the agar
surface by back and forth streaking with the inoculation loop over the solid
agar surface. This will make a dilution gradient across the agar plate. Upon
incubation, individual colonies will arise from the biomass.
The
characteristics features of the colonies on solid agar media are then noted.
This include
Shape
: circular, irregular or rhizoid.
- Size: small, medium, large( or in millimetres).
- Elevation: elevated, convex, concave, umbonate/umbilicate.
- Surface: Smooth, wavy, rough, granular, papillate or glistening.
- Edges: entire, undulate, crenated, fimbriate or curled.
- Colour: Yelow, green etc.( Note the colour of the colony).
- Structure: opaque, translucent or transparent.
- Degree of growth : scanty, moderate or profuse.
- Nature: discrete or confluent, filiform, spreading or rhizoid.
In
order to obtain the pure culture of organism, the isolated colonies are
aseptically transferred on to different nutrient agar slant tubes and incubated
overnight at 37 degree Celsius. It is then stored for future purpose.
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