Step 1:
Handling the test material obtained from a patient.Aspects of bacterial growth in liquid media:
o Diffuse turbidity
o Near-bottom and sidewall growth in a clear medium
o Surface film formation
o Cotton ball-like growth
Aspects of bacterial growth in semi-liquid media:
o Diffuse growth around the stab-inoculation site (motile bacteria)
o Growth along the way of stab inoculation (non-motile bacteria)
o Formation of gas bubblesAspects of bacterial growth on solid media:
o Growth as individual colonies
o Growth as a biofilm
Microbial culture properties:
1.The saccharolytic activity (ability to break down sugars)
and proteolytic activity (ability to break down proteins) are studied.To study the saccharolytic enzymes a pure bacterial culture is inoculated in Hiss
medium.Preliminary microscopic
examination of the smear is performed using the Gram staining to identify
microbial genus present in the test material.Examine the pattern of the bacterial culture growth on the agar slant and
confirm
the colony purity by microscopy (Gram staining).As the colonies are typical of each bacterial species, they are
an
important diagnostic aspect that enables to identify the bacterial genus and
species.Examination of the culture properties of isolated bacteria and description of
the
colony structure.Step 3:
There are three main methods for the determination of microbial species
(identification):
1.Inoculation of the test material on the culture medium using the streak plate
method.Colony size is determined by its diameter (large colonies -- over 4 mm in
diameter, medium colonies -- 2-4 mm, small colonies -- 1-2 mm, pin-point
colonies -- less than 1 mm).Colony shape -- round, amoeboid, root-shaped, etc.Degree of transparency -- opaque, clear.2.3.4.