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Pseudomonas grimontii sp. nov.
Summary
A novel species of fluorescent Pseudomonas, Pseudomonas grimontii, has been identified from French mineral waters. This bacterium is genetically distinct and represents a new addition to the Pseudomonas genus.
Area of Science:
- Microbiology
- Bacteriology
- Taxonomy
Background:
- A group of 43 bacterial strains, initially designated 'fluorescent Pseudomonas group 97-514', were isolated from French natural mineral waters.
- These strains exhibited common phenotypic characteristics including Gram-negative, rod-shaped morphology, motility via a single polar flagellum, and production of fluorescent pigment (pyoverdin).
Purpose of the Study:
- To characterize the 'fluorescent Pseudomonas group 97-514' and determine its taxonomic position within the genus Pseudomonas.
- To propose a new species designation based on comprehensive phenotypic and genotypic analyses.
Main Methods:
- Phenotypic characterization including Gram staining, motility tests, pigment production, metabolic profiling (catalase, oxidase, respiratory metabolism), and biochemical tests (arginine dihydrolase, poly-beta-hydroxybutyrate accumulation).
- DNA-DNA hybridization using the S1 nuclease method to assess genetic relatedness among the 43 strains and with other known Pseudomonas species.
- 16S rRNA gene sequencing for phylogenetic analysis.
- Determination of DNA G+C content and growth temperature range.
Main Results:
- The 43 strains formed a genetically homogeneous group with high DNA-DNA relatedness (70–100%) among themselves.
- These strains showed low DNA-DNA hybridization values (<56%) with other characterized Pseudomonas species, confirming their distinctiveness.
- Phylogenetic analysis based on 16S rRNA gene sequences placed the novel group within the 'Pseudomonas fluorescens intrageneric cluster'.
- Pseudomonas grimontii strains grew at 4°C but not 41°C and utilized specific carbon sources (D-xylose, alpha-L-rhamnose, alpha-aminobutyrate, meso-erythritol, itaconate) and formed levan from sucrose.
Conclusions:
- The 43 strains of 'fluorescent Pseudomonas group 97-514' represent a novel species within the genus Pseudomonas, for which the name Pseudomonas grimontii sp. nov. is proposed.
- The type strain is CFML 97-514T.
- Pseudomonas grimontii is phylogenetically related to Pseudomonas fluorescens but is phenotypically and genetically distinct.