[Taxonomic study of "Citrobacter freundii" biochemical variants (author's transl)].

Biochemical variants (ornithine-decarboxylase-positive and beta-galactosidase-negative) of Citrobacter freundii were characterized using numerical taxonomy, determination of deoxyribonucleic acid (DNA) base composition and DNA-DNA hybridization. Three clusters were detected by numerical taxonomy based on the assimilation of 146 carbohydrates. The atypical strains were dispersed into two clusters along with typical C. freundii strains. Furthermore, m-hydroxybenzoate metabolism, determination of base composition and DNA reassociation show that all three clusters are closely related. Therefore, the biochemical variants form a biogroup within C. freundii rather than a separate species.