THE FILAMENTOUS MORPHOTYPE EIKELBOOM TYPE-1863 IS NOT A SINGLE GENETIC ENTITY

Five isolates of a filamentous bacterial morphotype with the distincti ve diagnostic microscopic features of Eikelboom Type 1863 were obtaine d from activated sludge sewage treatment plants in Victoria, Australia . On the basis of phenotypic evidence and 16S rDNA sequence data, thes e isolates proved to be polyphyletic. Two (Ben 06 and Ben 06C) are fro m the Chryseobacterium subgroup which is in the Cytophaga group, subdi vision I of the Flexibacter-Cytophaga-Bacteroides phylum. Two (Ben 56 and Ben 59) belong to the genus Acinetobacter, and one (Ben 58) is a M oraxella sp., closest to Mor. osloensis. The significance of these fin dings to the reliance on microscopic features for identification of th ese filamentous bacteria in activated sludge is discussed.