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 Polymorphism (AFLP) analysis has revealed a possible genotypic resemblance of the species Aeromonas ichthiosmia and Aeromonas allosaccharophila to Aeromonas veronii (Huys et al., Int. J. Syst. Bacteriol. 46, 572-580 [19961). Currently, 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 12645T (= DSM 6393T), and that of A. allosaccharophila, LMG 14059T (= CECT 4199T), were 84-96% and 78-82% related to A. veronii strain LMG 9075T (= ATCC 35624T), respectively. Based upon phenotypic characterization including a total of 151 tests, the type strain of A. ichthiosmia could be clearly allocated to A. veronii biovar sobria. On the other hand, the three strains constituting the species A. allosaccharophila were found to be phenotypically heterogeneous. None of these strains clearly fitted the biochemical description of either of the two A. veronii biovars or tightly clustered with any of the A. veronii reference strains. On the basis of published taxonomic evidence (including AFLP and phylogenetic data) and the newly reported results, there is compiling evidence to conclude that A. ichthiosmia Schubert et al. 1990 is a later 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 proposal on the genotypic position of A. allosaccharophila should await further studies.