Dienes phenomena is seen with
A. Proteus mirabilisB. Klebsiella
C. Proteus vulgaris
D.Providentia
E. Morganella
Answer. A. Proteus
mirabilis ; (C) Proteus vulgaris
o By the help of Dienes phenomenon, swarming can be used to recognize
identical strain of Proteus.
— Strains isolated from a suspected
episode of hospital infection are spot inoculated around the edge of a culture
plate with one strain in the centre; seven strains per plate is appropriate.
Identical strains will shows no line of demarcation at the edges of swarming
area. Serological bacterial and phage type can also be employed by the
characterized strain.
Note: Dienes
method of staining is done to see the character of the
colony of Mycoplasma.
— The colony of Mycoplasma appears as ‘fried eggs appearance
— Danysz phenomenon:
If to a given amount of antitoxin, the
equivalent amount of toxin was added all at once the mixture remained non
toxic. If same amount is added in two or more installments at the intervals of 15 minutes or more, the resultant
mixture is toxic. This paradoxical occurrence is called danysz phenomenon. It
is due to ability of toxins and antitoxin to combine with more than its
equivalent of antitoxin, leaving insufficient anitoxin behind to neutralize the
toxin added subsequently.
