Phylogenetic positions of Aeromonas encheleia, Aeromonas popoffii, Aeromonas DNA hybridization Group 11 and Aeromonas Group 501

The 16S rDNA sequences of the recently described Aeromonas encheleia and Ae romonas popoffii, were determined and compared with data from all known Aer omonas sp. Diagnostic 16S rDNA regions were also sequenced for some strains previously considered as an extension of A. encheleia and a strain of Aero monas Group 501 (formerly Enteric Group 501). Results indicated that A. enc heleia and A. popoffii are phylogenetically separated species as originally described. A conclusion about HG11 taxonomic status is not recommended unt il previous discrepancies are clarified by further DNA-DNA hybridization an d sequencing studies.