Lactobacillus isalae sp. nov., isolated from the female reproductive tract

A novel strain of the genus Lactobacillus , named AMBV1719 T , was isolated from the vagina of a healthy participant in our large-scale citizen science project on the female microbiome, named Isala. Phylogenetic analysis showed that the 16S rRNA gene of AMBV1719 T is most similar to that of Lactobacillus taiwanensis with a sequence similarity of 99.873 %. However, a genome-wide comparison using average nucleotide identity (ANI) revealed that isolate AMBV1719 T showed the highest ANI with Lactobacillus paragasseri JCM 5343 T , with a value of only 88.17 %. This low ANI value with the most closely related strains known to date indicated that AMBV1719 T represents a distinct species. This strain has a limited ability to degrade carbon sources compared to Lactobacillus gasseri , indicating its adaptation to the host. Its genome has a length of 2.12 Mb with a G+C content of 34.8 mol%. We thus propose the name Lactobacillus isalae sp. nov. for this novel species, with AMBV1719 T (=LMG 32886 T =CECT 30756 T ) as the type strain.