Neobacillus camarae sp. nov. a new bacterium isolated from the breast milk of a senegalese mother breast-feeding a healthy child and genomic description of Neobacillus dielmonensis and Neobacillus drentensis

As part of a comprehensive study investigating the breast milk microbiota of healthy and malnourished children through a culturomic approach, a novel bacterial strain belonging to the genus Neobacillus was isolated, identified, and characterized using a taxonogenomic strategy. This isolate, designated as strain Marseille-QA0830ᵀ, was recovered from the breast milk of a mother nursing a healthy infant. Strain Marseille-QA0830ᵀ (= CSUR QA0830ᵀ = CECT 31295ᵀ) is a Gram-stain-positive, non-motile, aerobic, and non-spore-forming bacillus capable of growth under both aerobic and anaerobic conditions, at temperatures ranging from ambient to 45°C. With a genome size of 5.83 Mbp, strain Marseille-QA0830ᵀ exhibits a G + C content of 42.3%. Phylogenetic analysis based on the 16S rRNA gene revealed a high sequence similarity (99.4%) between strain Marseille-QA0830ᵀ and Neobacillus dielmonensis . However, significant genomic divergence was observed through digital DNA-DNA hybridization (dDDH), which showed only 26.2% similarity—well below the 70% threshold for species delimitation. Furthermore, rpoB gene analysis indicated a distant relationship with Neobacillus drentensis (83.5% similarity). Collectively, these genomic data demonstrate that although strain Marseille-QA0830ᵀ is phylogenetically closely related to N. dielmonensis based on 16S rRNA gene sequences, it remains distinct at the whole-genome and rpoB levels from previously described species within the Neobacillus nomenclature. These findings confirm that this isolate represents a unique and previously undescribed taxon. Consequently, we propose the description of the type strain Marseille-QA0830ᵀ as a new species named Neobacillus camarae sp. nov.