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

Deoxyribonucleic acid relatedness studies (S1 nuclease method) have shown that 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 Pseudomonas cedrella sp. nov. and Pseudomonas orientalis sp.nov. These strains were previously grouped on the basis of a numerical analysis in phenons Ve, Vd, Vg, and VI. DNA relatedness with 65 strains representing 24 species of the genus Pseudomonas sensu stricto was below 50%. The highest DNA binding value (50%) was found with P. marginalis species. A comparison of the complete 16S rRNA gene sequences of the strains representing the two new deoxyribonucleic acid hybridization groups, i.e., strains CFML 96-198T and CFML 96-170T, and the sequence of other strains of the genus Pseudomonas revealed that these strains (CFML 96-198T and CFML 96-170T) fell within the 'Pseudomonas fluorescens intrageneric cluster'. The G+C contents of the DNA of P. cedrella CIP 105541T and P. orientalis CIP 105540T were 59 and 60 mol%, respectively. The two species can be differentiated from each other by the fact that P. cedrella strains hydrolyze erythritol and D-lyxose. P. cedrella grouped together a total of nine strains from phenotypic groups Ve, Vg, and VI. P. orientalis grouped together six strains from both phenotypic groups Vd and Ve.

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

The taxonomic position of 23 strains isolated from mineral waters and previously grouped in the authentic pseudomonads on the basis of a phenotypic analysis (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 basis of hybridization results, these strains were gathered into two new genomic groups for which we propose the names of Pseudomonas jessenii sp. nov. (Type strain CIP 105274) and Pseudomonas mandelii sp. nov. (Type strain CIP 105273). Deoxyribonucleic acid relatedness levels showed homologies ranging from 78 to 100% for Pseudomonas jessenii and from 77 to 100% for Pseudomonas mandelii. Furthermore, hybrization rates with 66 representative well characterized species or only partially characterized species of the genus Pseudomonas were below 53%, with delta Tm values of 7 degrees C and more. The mol% G + C content ranged from 57 to 58. The two new species presented 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-glutamyl-L-histidine arylarmidase activity, growth on benzoate and meso-tartrate were found to differentiate Pseudomonas jessenii from Pseudomonas mandelii and from other Pseudomonas 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 significance is unknown. The 16S rDNA of each type strain was sequenced and compared with the known sequences of the representative strains of the genus Pseudomonas. A phylogenetic tree was constructed to determine the intrageneric relationships within the genus Pseudomonas.

Pseudomonas monteilii sp. nov., isolated from clinical specimens.

We propose the name Pseudomonas monteilii for a new species of gram-negative, rod-shaped, motile bacteria that were nonhemolytic on blood agar and were isolated from clinical sources. The 10 strains of P. monteilii were incapable of liquefing gelatin. They grew at 10 degrees C but not at 41 degrees C, produced fluorescent pigments, catalase, and cytochrome oxidase, and possessed the arginine dihydrolase system. They were capable of respiratory but not fermentative metabolism. They did not hydrolyze esculin or starch and were able to use benzylamine, alpha-aminobutyrate, D-ribose, L-arabinose, butyrate, valerate, isovalerate, isobutyrate, inositol, phenylacetate, D-alanine, and amylamine. They possessed L-phenylalanine arylamidase, L-lysine arylamidase, L-alanine arylamidase, gamma-glutamyl-transferase, glycyl-phenylalanine arylamidase, L-tryptophan arylamidase, glycyl-L-alanine arylamidase, esterase C4, esterase C6, esterase C8, esterase C9, esterase C10, and esterase C18. DNA relatedness studies revealed that P. monteilii strains formed a homogeneous DNA hybridization group. A total of 57 strains representing previously described or partially characterized taxa belonging to the genus Pseudomonas were 6 to 54% related to P. monteilii. The highest hybridization values were obtained with strains belonging to or related to Pseudomonas putida biovar A. The average G+C content of the DNA was 60.5 +/- 0.5 mol% for four of the P. monteilii strains studied. The type strain of P. monteilii is CFML 90-60 (= CIP 104883); it was isolated from bronchial aspirate and has a G+C content of 60 mol%. The clinical significance of these organisms is not known.

Pseudomonas libanensis sp. nov., a new species isolated from Lebanese spring waters.

The taxonomic position of eight fluorescent Pseudomonas isolates, from two Lebanese spring waters, which were previously recognized by numerical analysis as members of a new subcluster (subcluster Vb) was examined. Except for one strain, the new subcluster exhibited internal DNA hybridization values of 76-100%, and 9-53% hybridization was measured with the type or reference strains of other Pseudomonas species. The highest DNA binding value was found with Pseudomonas marginalis strains (37-53%). The G+C content of the DNA of the type strain was 58 mol%. A comparison of 1322 nt of the 16S rRNA gene sequence of the strain representing subcluster Vb (CFML 96-195T) with the sequence of other strains of the genus Pseudomonas revealed that strain CFML 96-195T was part of the 'Pseudomonas fluorescens intrageneric cluster'. On the basis of the results of phenotypic, DNA-DNA and phylogenetic analyses, a new Pseudomonas species, Pseudomonas libanensis sp. nov., is proposed for the seven strains of subcluster Vb. The type strain is P. libanensis CFML 96-195T and has been deposited in the Collection de l'Institut Pasteur (Paris, France) as CIP 105460T. The P. libanensis strains are phenotypically and genotypically homogeneous and can be differentiated from most other fluorescent species by several phenotypic features. Differentiation of P. libanensis and Pseudomonas aeruginosa is based mainly on pyocyanin production; P. libanensis can be differentiated from P. fluorescens (all biovars) by alpha-aminobutyrate assimilation. The clinical significance of P. libanensis is unknown.

Pseudomonas gessardii sp. nov. and Pseudomonas migulae sp. nov., two new species isolated from natural mineral waters.

Twenty-five non-identified fluorescent Pseudomonas strains isolated from natural mineral waters were previously clustered into three phenotypic subclusters, XIIIb, XVa and XVc. These strains were characterized genotypically in the present study. DNA-DNA hybridization results and DNA base composition analysis revealed that these strains were members of two new species, for which the names Pseudomonas gessardii sp. nov. (type strain CIP 105469T) and Pseudomonas migulae sp. nov. (type strain CIP 105470T) are proposed. P. gessardii included 13 strains from phenotypic subclusters XVa and XVc. P. migulae included 10 strains from phenotypic subcluster XIIIb. The levels of DNA-DNA relatedness ranged from 71 to 100% for P. gessardii and from 74 to 100% for P. migulae. The G + C content of the DNA of each type strain was 58 mol%. DNA similarity levels, measured with 67 reference strains of Pseudomonas species, were below 55%, with delta Tm values of 13 degrees C or more. The two new species presented basic morphological characteristics common to all pseudomonads. Various phenotypic features were found to differentiate them: P. gessardii strains utilized L-arabitol, myo-inositol, adonitol, xylitol and meso-erythritol as carbon sources, whereas P. migulae strains assimilated L-arabinose, D-xylose, D-saccharate, meso-tartrate, tricarballylate, D-glucuronate, D-galacturonate, phenylacetate and histamine. The complete 16S rRNA sequences of each type strain were determined and compared with those of the type strains of Pseudomonas species. Finally, a phylogenetic tree was inferred from sequence analysis and demonstrated that the two new species fell into the 'Pseudomonas fluorescens intrageneric cluster'. To date, their clinical significance is unknown.