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 DSM 27844 FF4T and Neobacillus drentensis LMG 21831T.

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 polyphasic strategy. This isolate, designated as strain Neobacillus camarae sp. nov. 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, non-spore-forming bacillus, facultatively anaerobic showing optimal growth under aerobic conditions but also capable of developing in anaerobic environment at temperatures ranging from 20 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 (98.10%) between strain Marseille-QA0830T and Neobacillus niacini NBRC 15566T (= IFO15566). A significant genomic divergence was observed through digital DNA-DNA hybridization (dDDH), against Neobacillus dielmonensis with 26.2% similarity well below the 70% threshold for species delineation. At the same time, rpoB gene analysis indicated a distant relationship with Neobacillus drentensis LMG 21831T (83.5% similarity). Collectively, these genomic data demonstrate that although strain Marseille-QA0830T is phylogenetically closely related to N. niacini NBRC 15566T 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.