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- Transfer of Pseudomonas pictorum Gray and Thornton 1928 to genus Stenotrophomonas as Stenotrophomonas pictorum comb. nov., and emended description of the genus Stenotrophomonas doi link

Auteur(s): Ouattara Aboubakar Sidiki, Le Mer J., Joseph M., Macarie Hervé

(Article) Publié: International Journal Of Systematic And Evolutionary Microbiology, vol. 67 p.1894 - 1900 (2017)


Ref HAL: ird-01563113_v1
DOI: 10.1099/ijsem.0.001880
Exporter : BibTex | endNote
Résumé:

Transfer of Pseudomonas pictorum Gray and Thornton 1928 to genus Stenotrophomonas as Stenotrophomonas pictorum comb. nov., and emended description of the genus Stenotrophomonas Abstract A polyphasic taxonomic approach including analysis of phenotypic, physiological and genotypic characteristics, 16S rRNA gene sequence and DNA–DNA hybridization analysis was used to determine the most consistent affiliation of Pseudomonas pictorum. Pseudomonas pictorum ATCC 23328 T exhibited phenotypic traits of members of the genus Stenotrophomonas including cellular fatty acid composition, quinone and limited range of substrates that could be used. Antibiotic susceptibility and physiological characteristics were determined. The DNA G+C content was 65.7 mol%. Phylogenetic analysis revealed that the type strains of Stenotrophomonas terrae, Stenotrophomonas humi, Stenotrophomonas nitritireducens and Stenotrophomonas acidaminiphila were the nearest relatives (16S rRNA gene sequence similarity of 98.0 to 98.8 %). All the other type strains of species of the genus Stenotrophomonas showed high 16S rRNA gene sequence similarities (96.8 to 97.2 %). DNA–DNA hybridizations revealed 31.0, 32.0, 43.3 and 43.6 % reassociation between Pseudomonas pictorum ATCC 23328 T and the type strains of S. terrae, S. humi, S. nitritireducens and S. acidaminiphila, respectively. Our overall results indicate that Pseudomonas pictorum should be transferred to the genus Stenotrophomonas as a novel species of this genus, Stenotrophomonas pictorum comb. nov. Since the original description of the genus Stenotrophomonas was made with only one species (Stenotrophomonas maltophilia), an emendation of the genus description is proposed in order to match better with the characteristics of the eleven novel species assigned to this genus since then. The first description of Pseudomonas pictorum proposed by Gray and Thornton [1] was a report of the phenotypic characteristics of cells and morphology of colonies. Over the years, phenotypic studies (cellular fatty acid composition, quinone type content of cells, polyamine pattern and ester-ase polymorphism) and phylogenetic analysis (16S rRNA gene sequences, gyrB sequence, full genome sequence) have clearly pointed out that Pseudomonas pictorum should rather be reclassified within the family Xanthomonadaceae lineage and that its closest relatives are species of the genus Stenotrophomonas [2–12]. As a consequence, the type strain of Pseudomonas pictorum has been included in several studies concerning the genomic and phenotypic diversity of the genus Stenotrophomonas in which this type strain was even sometimes presented as a member of Stenotrophomonas maltophilia, with which, however, it shows only 30 % DNA– DNA reassociation [4, 13, 14]. Despite this body of evidence and wide acceptance, Pseudomonas pictorum has still not been formerly assigned to the genus Stenotrophomonas. The aim of the present study was to determine the most consistent taxonomic position of Pseudomonas pictorum by a polyphasic taxonomic approach including analysis of phe-notypic, physiological and genotypic (16S rRNA gene sequence similarities and DNA–DNA hybridization) properties and characteristics of this species. Since no other Pseudomonas pictorum strain than the type strain is presently available in public culture collections and all the accessible cultures of the type strain are derived from the strain deposited in the Czech collection of microorganisms under the number CCM 284 T , our study was limited to the type strain. Cultures of all the type strains were prepared using nutrient broth media (3 g meat extract l À1 , 5 g peptone l À1 , 5 g yeast extract l À1). Unless otherwise indicated, cultures of microorganisms for performing phenotypic tests were prepared