VI. IDENTIFICATION OF .4CTINOMYCES AND ARACHNIA
313
all these studies we obtained about 75% agreement between culture and
FA results with only a single culture from each specimen.
Holmberg and Forsum (1973) also observed four Actinomyces species and
Arachnia in direct smears of dental plaque from 20 individuals with
periodontal disease. They found A . israelii, A . naeslundii and Arachnia
propionica primarily in subgingival specimens while A . viscosus, A . naeshndii and A . odontolyticus were found in supragingival sites. I n this study,
88% agreement between direct FA and culture was obtained after repeat
culture of some FA positive, culturally negative specimens.
I n a later study of Gram-positive rods in dental plaque, Holmberg (1976)
studied 446 isolates. Of these, 75 were identified as A . viscosus, 92 as
A . naeslundii, 14 as A . odontolyticus, 51 as A . israelii and 33 as Arachnia
propionica on the basis of biochemical tests and serology. Fifteen of the
446 isolates were lost before biochemical tests could be done, but eight of
them were identified by FA staining as Actinomyces. Both serotypes of A.
israelii were isolated, but only one serotype of each of the other species,
namely A . viscosus, two; A . naeslundii, one; A . odontolyticus, one and
,4rachnia propionica, one, were identified. All the organisms identified as
Actinomyces or Arachnia by biochemical tests reacted in the appropriate
antiserum. Direct smears of the plaque were also examined by FA in this
study. The overall agreement between cultural and FA identification was
79%.
VI. OTHER SEROLOGICAL TECHNIQUES
A. Cell wall agglutination
Other serological techniques have been used for identifying Actinomyces.
The agglutination test was widely used by early workers (reviewed by
Slack et al., 1951) and is still used to some extent (Bellack and Jordan,
1972). Agglutination tests are convenient to use but are not completely
satisfactory because it is difficult to produce homogeneous antigens which
will not autoagglutinate. Agglutination tests using cell walls instead of
whole cells have been used for studying Actinomyces (Cummins, 1962; in
Slack and Gerencser, 1975) and Arachnia (Johnson and Cummins, 1972).
The species of Actinomyces could be separated by cell wall agglutination
although high-titred cross-reactions occurred with A . naeslundii serotype
1 cell walls and both A. israelii serotype 1 and A . viscosus serotype 2
antisera. Serotype 1 strains of Arachnia propionica did not react in cell wall
agglutination tests with the serotype 2 strain.
Bowden and Hardie (1973) and Bowden et al. (1976) demonstrated cell
wall associated antigens which were generally species specific using
trypsin or pronase treated cell walls in agglutination tests. Specific titres
313
all these studies we obtained about 75% agreement between culture and
FA results with only a single culture from each specimen.
Holmberg and Forsum (1973) also observed four Actinomyces species and
Arachnia in direct smears of dental plaque from 20 individuals with
periodontal disease. They found A . israelii, A . naeslundii and Arachnia
propionica primarily in subgingival specimens while A . viscosus, A . naeshndii and A . odontolyticus were found in supragingival sites. I n this study,
88% agreement between direct FA and culture was obtained after repeat
culture of some FA positive, culturally negative specimens.
I n a later study of Gram-positive rods in dental plaque, Holmberg (1976)
studied 446 isolates. Of these, 75 were identified as A . viscosus, 92 as
A . naeslundii, 14 as A . odontolyticus, 51 as A . israelii and 33 as Arachnia
propionica on the basis of biochemical tests and serology. Fifteen of the
446 isolates were lost before biochemical tests could be done, but eight of
them were identified by FA staining as Actinomyces. Both serotypes of A.
israelii were isolated, but only one serotype of each of the other species,
namely A . viscosus, two; A . naeslundii, one; A . odontolyticus, one and
,4rachnia propionica, one, were identified. All the organisms identified as
Actinomyces or Arachnia by biochemical tests reacted in the appropriate
antiserum. Direct smears of the plaque were also examined by FA in this
study. The overall agreement between cultural and FA identification was
79%.
VI. OTHER SEROLOGICAL TECHNIQUES
A. Cell wall agglutination
Other serological techniques have been used for identifying Actinomyces.
The agglutination test was widely used by early workers (reviewed by
Slack et al., 1951) and is still used to some extent (Bellack and Jordan,
1972). Agglutination tests are convenient to use but are not completely
satisfactory because it is difficult to produce homogeneous antigens which
will not autoagglutinate. Agglutination tests using cell walls instead of
whole cells have been used for studying Actinomyces (Cummins, 1962; in
Slack and Gerencser, 1975) and Arachnia (Johnson and Cummins, 1972).
The species of Actinomyces could be separated by cell wall agglutination
although high-titred cross-reactions occurred with A . naeslundii serotype
1 cell walls and both A. israelii serotype 1 and A . viscosus serotype 2
antisera. Serotype 1 strains of Arachnia propionica did not react in cell wall
agglutination tests with the serotype 2 strain.
Bowden and Hardie (1973) and Bowden et al. (1976) demonstrated cell
wall associated antigens which were generally species specific using
trypsin or pronase treated cell walls in agglutination tests. Specific titres