DNA relatedness among Pseudomonas strains isolated from natural mineral waters and proposal of Pseudomonas veronii sp. nov.

Abstract

The taxonomic position of eight strains isolated from mineral water and previously grouped in the authentic pseudomonads on the basis of a phenotypic analysis (cluster Ib of M. Elomari, L. Coroler, D. Izard, and H. Leclerc [J. Appl. Bacteriol. 78:71-81, 1995]) has been further studied by DNA-DNA hybridizations. Using the S1 nuclease method at 60 degrees C and labeled reference DNA from a representative strain, CFML 92-134, we showed that members of cluster Ib constituted a homogeneous group with a relative binding ratio of greater than 80% and changes in melting temperature of less than 1 degree C. With a total of 67 strains representing known or partially characterized species of the genus Pseudomonas, only 4 to 47% DNA hybridization and changes in melting temperature of between 8 and 20 degrees C were found, the highest hybridization values being measured with members of the saprophytic fluorescent pseudomonads. Since cluster Ib could also be clearly differentiated from members of the latter group and from other phenotypic clusters containing isolates from mineral water, we designated the Ib strains members of a new Pseudomonas species for which the name Pseudomonas veronii sp. nov. has been proposed. Members of this species grew on alpha-aminobutyrate, sucrose, butyrate, isobutyrate, erythritol, L-tryptophan, and trigonelline as sole sources of carbon and energy. The average G+C content of the DNA of the eight strains of P. veronii was 61.5 +/- 0.5 mol%. The type strain is CFML 92-134T (CIP 104663T), with a G+C content of 61 mol%. The clinical significance of P. veronii is unknown.