The application of serological techniques to the taxonomy of Arthrobacter and related organisms

Antisera were raised against rods of 17 named Arthrobacter and Aureobacterium strains. Antigenic relationships between these strains, other soil bacteria and new Arthrobacter isolates from several soils were studied, using agglutination, immunodiffusion, immunofluorescence and ELISA techniques. Many of the named Arthrobacter species had common antigens, and there were also common antigens amongst named Arthrobacter strains and many fresh Arthrobacter isolates. Agglutination, ELISA and immunofluorescence tests revealed greater antigenic differences between the named strains than did immunodiffusion tests. Serological similarities between the 17 named strains and the fresh Arthrobacter isolates were calculated using SJ coefficients. The occurrence of named strains in serogroups based on immunodiffusion data supported the taxonomic scheme for arthrobacters in Bergey's Manual of Systematic Bacteriology. The distribution of soil isolates in serogroups resembled that in groups based on numerical analysis of diverse characters. This makes it possible to use serological tests to locate particular species in soil samples. Arthrobacter atrocyaneus was serologically distinct from other members of the Ar. globiformis/Ar. citreus group and did not cluster with them phenetically. Serological data suggest that Ar. aurescens, Ar. ureafaciens and Ar. histidinolovorans constitute a single species. Although A. simplex and A. tumescens have been placed in the genus Pimelobacter, they are serologically distinct from one another and more closely resemble Ar. globiformis. Aureobacterium strains were serologically distinct from arthrobacters. Micrococcus roseus showed many cross-reactions with several antisera, supporting the placement of micrococci in the same family as arthrobacters.