318
M. A. GERENCSER
identify strains which do not survive in culture long enough for complete
biochemical studies or which are non-viable when received by a reference
laboratory.
Secondly, the application of FA to direct smears of clinical material
frequently permits a diagnosis of actinomycosis to be made before cultures
are available. Perhaps more important, it permits a diagnosis to be made
when cultures are negative or when appropriate cultures were not carried
out. Even today, a diagnosis of actinomycosis is often based on the demonstration of granules containing Gram-positive filaments in a tissue specimen, although a variety of bacteria may resemble Actinomyces morphologically and produce similar granules in tissue (Slack and Gerencser, 1975).
In fact such, often dubious, cytological evidence coupled with the clinical
symptoms form the basis for the diagnosis in the majority of cases. The
regular use of available FA techniques in the diagnosis of actinomycosis
would provide a more accurate diagnosis for the individual patient and
would also provide epidemiological data which is now lacking.
With the increasing interest in oral microbiology, caries and periodontal
disease, it should be pointed out that FA is a valuable tool for studying oral
ecology. It can be used for the identification of Actinomyces in plaque,
calculus and other oral samples and for following experimental infections.
The advantages of FA are so obvious that it is sometimes easy to overlook
the limitations of the method but these should be kept in mind. Identification of any bacterium by FA is based on only two parameters, morphology and the specificity of a serological reaction. As in any other
serological test, cross-reactions due to related antigens may occur and the
reagents used may not contain antibodies to all strains of a given organism.
I n the case of Actinomyces, all available evidence indicates that species
specificity of the antiserum can be achieved. Some isolates which do not
stain with available FA reagents may represent new serotypes or species.
This means that while positive FA reactions are reliable, negative reactions
of organisms resembling Actinomyces morphologically cannot be used to
rule out the possibility of Actinomyces. This does not seriously detract from
the value of the method since the great majority of clinical isolates do give
positive FA reactions. I n fact, the greatest disadvantage of FA at the moment is the lack of commercially available reagents for Actinomyces.
FA which has been so successful in providing accurate identification of
the pathogenic agent, is apparently not the method of choice in developing
a serological test for actinomycosis. A serological test for the disease would
further improve the ability of the laboratory to aid in the diagnosis of
actinomycosis. Other serological tests, such as the CIE test described by
Holmberg et al. (1975b), seem more promising for the purpose.
For the future, the value of FA tests will be improved by the continued
M. A. GERENCSER
identify strains which do not survive in culture long enough for complete
biochemical studies or which are non-viable when received by a reference
laboratory.
Secondly, the application of FA to direct smears of clinical material
frequently permits a diagnosis of actinomycosis to be made before cultures
are available. Perhaps more important, it permits a diagnosis to be made
when cultures are negative or when appropriate cultures were not carried
out. Even today, a diagnosis of actinomycosis is often based on the demonstration of granules containing Gram-positive filaments in a tissue specimen, although a variety of bacteria may resemble Actinomyces morphologically and produce similar granules in tissue (Slack and Gerencser, 1975).
In fact such, often dubious, cytological evidence coupled with the clinical
symptoms form the basis for the diagnosis in the majority of cases. The
regular use of available FA techniques in the diagnosis of actinomycosis
would provide a more accurate diagnosis for the individual patient and
would also provide epidemiological data which is now lacking.
With the increasing interest in oral microbiology, caries and periodontal
disease, it should be pointed out that FA is a valuable tool for studying oral
ecology. It can be used for the identification of Actinomyces in plaque,
calculus and other oral samples and for following experimental infections.
The advantages of FA are so obvious that it is sometimes easy to overlook
the limitations of the method but these should be kept in mind. Identification of any bacterium by FA is based on only two parameters, morphology and the specificity of a serological reaction. As in any other
serological test, cross-reactions due to related antigens may occur and the
reagents used may not contain antibodies to all strains of a given organism.
I n the case of Actinomyces, all available evidence indicates that species
specificity of the antiserum can be achieved. Some isolates which do not
stain with available FA reagents may represent new serotypes or species.
This means that while positive FA reactions are reliable, negative reactions
of organisms resembling Actinomyces morphologically cannot be used to
rule out the possibility of Actinomyces. This does not seriously detract from
the value of the method since the great majority of clinical isolates do give
positive FA reactions. I n fact, the greatest disadvantage of FA at the moment is the lack of commercially available reagents for Actinomyces.
FA which has been so successful in providing accurate identification of
the pathogenic agent, is apparently not the method of choice in developing
a serological test for actinomycosis. A serological test for the disease would
further improve the ability of the laboratory to aid in the diagnosis of
actinomycosis. Other serological tests, such as the CIE test described by
Holmberg et al. (1975b), seem more promising for the purpose.
For the future, the value of FA tests will be improved by the continued