Taxonomic study of bacteria isolated from natural mineral waters: Proposalof Pseudomonas jessenii sp. nov. and Pseudomonas mandelii sp. nov.

The taxonomic position of 23 strains isolated from mineral waters and previ ously grouped in the authentic pseudomonads on the basis of a phenotypic an alysis (cluster IX, subclusters XIIIa and XIIIc of VERHILLE, S., ELOMARI, M ., COROLER, L., IZARD, D., LECLERC, H. (Syst. Appl. Microbiol. 20, 137-149, 1997) has been genotypically further studied in the present work. On the b asis of hybridization results, these strains were gathered into two new gen omic groups for which we propose the names of Pseudomonas jessenii sp. nov. (Type strain CIP 105274(T)) and Pseudomonas mandelii sp. nov. (Type strain CIP 105273(T). Deoxyribonucleic acid relatedness levels showed homologies ranging from 78 to 100% for Pseudomonas jessenii and from 77 to 100% for Ps eudomonas mandelii. Furthermore, hybridization rates with 66 representative well characterized species or only partially characterized species of the genus Pseudomonas were below 53%, with Delta T-m values of 7 degrees C and more. The mol% G+C content ranged from 57 to 58. The two new species presen ted basic morphological characteristics common to all pseudomonads. Various phenotypic features, such as denitrification, growth at 4 degrees C or 41 degrees C, trigonelline assimilation, alpha-L-glulamyl-L-histidine arylamid ase activity, growth on benzoate and mese-tartrate were found to differenti ate Pseudomonas jessenii from Pseudomonas mandelii and from other Pseudomon as species. Pseudomonas jessenii encompassed a total of 9 strains from both phenotypic groups IX and XIIIa. Pseudomonas mandelii clustered a total of 13 strains from both phenotypic groups IX and XIIIc. Their clinical signifi cance is unknown. The 16S rDNA of each type strain was sequenced and compar ed with the known sequences of the representative strains of the genus Pseu domonas. A phylogenetic tree was constructed to determine the intrageneric relationships within the genus Pseudomonas.