New DNA-DNA hybridization and phenotypic data on the species Aeromonas ichthiosmia and Aeromonas allosaccharophila: A-ichthiosmia Schubert et al. 1990 is a later synonym of A-veronii Hickman-Brenner et al. 1987

Previously, a DNA fingerprinting study based on Amplified Fragment Length P olymorphism (AFLP) analysis has revealed a possible genotypic resemblance o f the species Aeromonas ichthiosmia and Acromonas allosaccharophila to Aero monas veronii (Huys et al., Int. J. Syst. Bacteriol. 46, 572-580 [1996]). C urrently, two genotypically indistinguishable biovars are known to exist in the latter species, namely A. veronii biovar sobria and A. veronii biovar veronii. In the current study, new DNA-DNA hybridization experiments showed that the type strain of A. ichthiosmia, LMG 12645(T) (= DSM 6393(T)), and that of A. allosaccharophila, LMG 14059(T) (= CECT 4199(T)), were 84-96% an d 78-82% related to A. veronii strain LMG 9075(T) (= ATCC 35624(T)), respec tively. Based upon phenotypic characterization including a total of 151 tes ts, the type strain of A. ichthiosmia could be clearly allocated to A. vero nii biovar sobria. On the other hand, the three strains constituting the sp ecies A. allosaccharophila were found to be phenotypically heterogeneous. N one of these strains clearly fitted the biochemical description of either o f the two A. veronii biovars or tightly clustered with any of the A. veroni i reference strains. On the basis of published taxonomic evidence (includin g AFLP and phylogenetic data) and the newly reported results, there is comp iling evidence to conclude that A. ichthiosmia Schubert et al. 1990 is a la ter synonym of A. veronii Hickman-Brenner et al. 1987. However, due to the lack of agreement encountered between the new DNA reassociation results and previously reported DNA homology and phylogenetic data, a conclusive propo sal on the genotypic position of A. allosaccharophila should await further studies.