Taxonomic study of bacteria isolated from Lebanese spring waters: proposalfor Pseudomonas cedrella sp nov and P-orientalis sp nov.

Deoxyribonucleic acid relatedness studies (S1 nuclease method) have shown t hat 15 strains isolated from three Lebanese spring waters, belonging to the genus Pseudomonas, formed two homogeneous DNA groups, with a within-group DNA relatedness ranging from 70 to 100%. These groups are referred to as Ps eudomonas cedrella sp. nov. and Pseudomonas orientalis sp.nov. These strain s were previously grouped on the basis of a numerical analysis in phenons V e, Vd, Vg, and VI. DNA relatedness with 65 strains representing 24 species of the genus Pseudomonas sensu stricto was below 50%. The highest DNA bindi ng value (50%) was found with P. marginalis species. A comparison of the co mplete 16S rRNA gene sequences of the strains representing the two new deox yribonucleic acid hybridization groups, i.e., strains CFML 96-198(T) and CF ML 96-170(T), and the sequence of other strains of the genus Pseudomonas re vealed that these strains (CFML 96-198(T) and CFML 96-170(T)) fell within t he 'Pseudomonas fluorescens intrageneric cluster'. The G+C contents of the DNA of P. cedrella CIP 105541(T) and P. orientalis CIP 105540(T) were 59 an d 60 mol%, respectively. The two species can be differentiated from each ot her by the fact that P. cedrella strains hydrolyze erythritol and D-lyxose. P. cedrella grouped together a total of nine strains from phenotypic group s Ve, Vg, and VI. I? orientalis grouped together six strains from both phen otypic groups Vd and Ve. (C) Elsevier, Paris.