111. TYPING OF E. INSIDIOSA
59
only a weakly positive or a negative haemagglutination reaction. Strains
belonging to serogroup B or N showed strong haemadsorption abilities.
Using the haemagglutination reaction, serogroup B and N strains gave
high haemagglutination titres in comparison with strains of serogroup A
but there was no sharp distinction between the three groups.
The results of typing by the various methods are summarised in Table I.
IV. DISCUSSION
Of the 85 strains of E. insidiosa studied 30 reacted with A group antiserum, 47 with B group serum and eight did not react with either. Naturally
the serological approach is considered the most reliable and these results
form the basis of allocation of strains to groups.
The results with bacteriophage show a close correlation with serological
grouping. Brill and Politynska (1961) explain the occurrence of exceptional
lysis seen with old laboratory cultures of serogroup B strains in terms of a
change of cell specific antigen. These authors propose that it is necessary
only to use the A specific bacteriophage for typing E. insidiosa. Revenko
(1968) has also reported the existence of B and N group phages. These
remain to be studied for their application to typing. Representatives of
all three groups are found to have pathological and immunological significance.
The haemadsorption reaction proves to be particularly significant for
the typing of E. insidiosa. All the strains serologically typed as group A
failed to adsorb poultry erythrocytes to a significant extent while those of
groups B and N show a markedly positive reaction.
Bacteriophage and haemadsorption tests provide useful auxiliary typing
methods. They are simple to perform and can be carried out in most
laboratories. Undoubtedly, however, the most useful method is serological
typing based on microprecipitation in agar. This method is accurate and
differentiates clearly between the three serogroups. The extraction method
is simple and the specific antisera are highly potent, such that 1 ml of
serum will enable hundreds of strains to be typed. Results can conveniently
be read in one working day and the interpretation of the precipitin lines is
normally unequivocal.
REFERENCES
Atkinson, N. (1941). Aust. J , exp. Biol. med. Sci. 19, 45-50.
Brill, J. and Politynska, E. (1961). Zbl. BuRt. I Orig. 181, 473477.
Brill, J., Mikulaszek, E. and Truszezynski, M. (1959). Zbl. Bukt. I Orig. 176,
Bukrinskaia, A. G. (1960). “Woprosi virusologii” N2.
468475.
59
only a weakly positive or a negative haemagglutination reaction. Strains
belonging to serogroup B or N showed strong haemadsorption abilities.
Using the haemagglutination reaction, serogroup B and N strains gave
high haemagglutination titres in comparison with strains of serogroup A
but there was no sharp distinction between the three groups.
The results of typing by the various methods are summarised in Table I.
IV. DISCUSSION
Of the 85 strains of E. insidiosa studied 30 reacted with A group antiserum, 47 with B group serum and eight did not react with either. Naturally
the serological approach is considered the most reliable and these results
form the basis of allocation of strains to groups.
The results with bacteriophage show a close correlation with serological
grouping. Brill and Politynska (1961) explain the occurrence of exceptional
lysis seen with old laboratory cultures of serogroup B strains in terms of a
change of cell specific antigen. These authors propose that it is necessary
only to use the A specific bacteriophage for typing E. insidiosa. Revenko
(1968) has also reported the existence of B and N group phages. These
remain to be studied for their application to typing. Representatives of
all three groups are found to have pathological and immunological significance.
The haemadsorption reaction proves to be particularly significant for
the typing of E. insidiosa. All the strains serologically typed as group A
failed to adsorb poultry erythrocytes to a significant extent while those of
groups B and N show a markedly positive reaction.
Bacteriophage and haemadsorption tests provide useful auxiliary typing
methods. They are simple to perform and can be carried out in most
laboratories. Undoubtedly, however, the most useful method is serological
typing based on microprecipitation in agar. This method is accurate and
differentiates clearly between the three serogroups. The extraction method
is simple and the specific antisera are highly potent, such that 1 ml of
serum will enable hundreds of strains to be typed. Results can conveniently
be read in one working day and the interpretation of the precipitin lines is
normally unequivocal.
REFERENCES
Atkinson, N. (1941). Aust. J , exp. Biol. med. Sci. 19, 45-50.
Brill, J. and Politynska, E. (1961). Zbl. BuRt. I Orig. 181, 473477.
Brill, J., Mikulaszek, E. and Truszezynski, M. (1959). Zbl. Bukt. I Orig. 176,
Bukrinskaia, A. G. (1960). “Woprosi virusologii” N2.
468475.