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

A novel strain of the genus Lactobacillus, named AMBV1719T, was isolated from the vagina of a healthy participant in our largescale citizen science project on the female microbiome, named Isala. Phylogenetic analysis showed that the 16S rRNA gene of AMBV1719T 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 AMBV1719T showed the highest ANI with Lactobacillus paragasseri JCM 5343T, with a value of only 88.17 %. This low ANI value with the most closely related strains known to date indicated that AMBV1719T 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 AMBV1719T (=LMG 32886T=CECT 30756T) as the type strain.