Pseudomonas senegalensis sp. nov. and Pseudomonas millioni sp. nov., two novel species isolated from the breast milk of Senegalese women.

Two Gram-negative, aerobic, motile and non-spore-forming bacilli, designated strains Marseille-QA0332T and Marseille-QA0892T, were isolated from the breast milk of nursing mothers in Senegal. Because both strains failed to be identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, a comprehensive taxonogenomic approach was employed to determine their taxonomic positions. The complete genomes consist of single circular chromosomes of 4,577,173 bp (63.65 mol% G + C) for strain Marseille-QA0332T and 4,658,126 bp (60.22 mol% G + C) for strain Marseille-QA0892T. The 16S rRNA gene analysis revealed a sequence similarity of 97.98% between strain Marseille-QA0332T and Pseudomonas ceruminis BML-PP028T, while Pseudomonas muyukensis COW39T was identified as its closest relative based on digital DNA-DNA hybridization (dDDH 26.7%) and whole genome phylogeny on Average Nucleotide Identity (ANIb 81.3%). For strain Marseille-QA0892T, the 16S rRNA gene sequence showed 99.00% similarity to Pseudomonas matsuisoli JCM_30078T , its closest relative, with an ANIb of 75.0% and a dDDH value of 21.1%. All pairwise genomic values remained well below the established thresholds for bacterial species delineation, and whole genome phylogeny confirmed the stable placement of both novel lineages within the genus Pseudomonas. Based on these polyphasic results, we propose the description of two novel species, Pseudomonas senegalensis sp. nov. (Marseille-QA0332T = CSUR QA0332 = CECT 31294; GenBank accession number JBUCKV000000000) and Pseudomonas millioni sp. nov. (Marseille-QA0892T = CSUR QA0892 = CECT 31318; GenBank accession number JBUCKW000000000).