The phylogenetic structure of the genus Acinetobacter.

16S rDNA sequence analysis was performed on the type strains of all validly described Acinetobacter species and five unnamed Acinetobacter strains. The phylogenetic analyses confirm that Acinetobacter is a coherent genus within the gamma subclass of Proteobacteria and that the species are phylogenetically well defined. A. calcoaceticus, A. lwoffii, A. johnsonii and A. haemolyticus form one cluster of closely related species, the pair A. junii and A. baumannii forms a second cluster. A. radioresistens stands phylogenetically isolated. The study reveals that three undescribed strains can be assigned to individually described species, while strains DSM 30009 and DSM 590 may represent two novel Acinetobacter species.