Comparative Genomic Study of Lactobacillus jensenii and the Newly Defined Lactobacillus mulieris Species Identifies Species-Specific Functionality.

Lactobacilli are dominant members of the "healthy" female urogenital microbiota. One of these species, , is routinely identified in the urinary microbiota of women both with and without urinary tract symptoms. In March 2020, the new bacterial species was introduced, and phylogenetic and average nucleotide identity analysis identified eight strains that should be classified as members of the species. This prompted our phylogenomic study of all publicly available and genome sequences. While there is little variation in the 16S rRNA gene sequences, the core genome shows a clear distinction between genomes of the two species. We find eight additional strains of the species among these genomes. Furthermore, one strain, currently classified as UMB7784, is distinct from both and strains. As part of our comparative genomic study, we also investigated the genetic content that distinguishes these two species. Unique to the genomes are several genes related to catabolism of disaccharides. In contrast, genomes encode several cell surface and secreted proteins that are not found within the genomes. These -specific and -specific loci provide insight into phenotypic differences of these two species. species play a key role in the health of the urinary tract. For instance, and have been found to inhibit uropathogenic growth. While is typically found only within the microbiota of women without lower urinary tract symptoms (LUTS), has been found in the microbiota of women both with and without LUTS. With the recent introduction of the new species , several strains of were reclassified as based upon gene marker and average nucleotide identity. We took a phylogenomic and comparative genomic approach to ascertain the genetic determinants of these two species. Looking at a larger data set, we identified additional strains, including one distinct from other members of the species- UMB7784. Furthermore, we identified unique loci in each species that may have clinical implications.