Aeromonas aquatica sp nov., Aeromonas finlandiensis sp nov and Aeromonas lacus sp nov isolated from Finnish waters associated with cyanobacterial blooms

Three groups of Aeromonas strains isolated from Finland lakes experiencing cyanobacterial blooms could not be assigned to any known species of this genus on the basis of 16S rRNA and rpoD gene sequences. The Multilocus Phylogenetic Analysis (MLPA) of the concatenated sequence of seven genes (gyrB, rpoD, recA, dnaJ, gyrA, dnaX and atpD; 4093 bp) showed that the three groups of strains did not cluster with any known Aeromonas spp. and formed three independent lineages. This was confirmed by performing the analysis with their closest relatives using 15 genes (the latter 7 and cpn60, dnaK, gltA, mdh, radA, rpoB, tsf, zipA; 8751 bp). Furthermore, ANI results between the genomes of the type strains of the three potential new species and those of their close relatives were all <96% which is the previously proposed cutoff value for differentiating species within this genus. The in silico DDH values of the three type strains of the new species also showed a similarity <70% with the most closely related species indicating they belong to different taxa. The three groups of strains could be differentiated from each other and from other known Aeromonas species on the basis of several phenotypic characters. This polyphasic study revealed that the 3 groups of strains represent 3 novel Aeromonas species for which the names Aeromonas aquatica sp. nov. (type strain AE235(T) = CECT 8025(T) = LMG 26712(T)), Aeromortas finlandiensis sp. nov. (type strain 4287D(T) = CECT 8028(T) = LMG 26709(T)) and Aeromonas lacus sp. nov. (type strain AE122(T) = CECT 8024(T) = LMG 26710(T)) are proposed. (C) 2015 Elsevier GmbH. All rights reserved.