Studies with microaerophilic actinomycetes. I. The agglutination reaction.

Although some seventy years have passed since the earliest descriptions of microaerophilic actinomycetes, there is still considerable debate concerning their identification and their classification. In all probability the final answer to these vexing problems will require the application of one or more serological procedures. It was with this in mind that the following studies were undertaken. The literature concerning serological investigations with microaerophilic and aerobic actinomycetes has not been extensively reviewed by any one author although the papers of Erickson (1940) and Ludwig and Hutchinson (1949) are more valuable in this regard than any of the others encountered. Thus, it was thought that a rather extensive review of the literature stressing particularly the agglutination reaction would be of value. Probably the first report on serological investigations with the actinomycetes is that of Biagi (1904), who describes the immunization of rabbits with five species of aerobic actinomycetes and the cross agglutinations among the species. Agglutinations were also tried with the antisera and the tubercle bacillus. Homologous and heterologous agglutination with the actinomycetes was obtained in low titer. The tubercle bacillus was not agglutinated by any of the antisera. It is interesting to note that his reason for doing these tests was to try to find a method of classifying the organisms other than that using morphology and physiology. In the same year di Donna (1904) immunized rabbits with a Streptothrix and was able to demonstrate agglutinins. Calendoli (1905) used the same culture as di Donna as well as another Streptothrix and was able to show some cross-agglutination reaction between the two organisms. Fritzsche (1908) killed, dried, and ground the sediment from broth cultures of actinomycetes and immunized animals with this material. The agglutinin titer was low, and cross reactions between aerobic actinomycetes and Mycobacterium were common. Complement fixation tests also gave frequent cross reactions. Neither actinomycetes nor avirulent species of Mycobacterium immunized guinea pigs against the tubercle bacillus. Choukevitch (1909) immunized rabbits with seven species of aerobic actino-