Bifidobacterium longum subsp. iuvenis subsp. nov., a novel subspecies isolated from the faeces of weaning infants
Monica Modesto, Catherine Ngom‐Bru, Donatella Scarafile, Anne Bruttin, Solenn Pruvost, Shafiqul Alam Sarker, Tahmeed Ahmed, Olga Sakwińska, Paola Mattarelli, Stéphane Duboux
Abstract
The species Bifidobacterium longum currently comprises four subspecies: B. longum subsp. longum , B. longum subsp. infantis , B. longum subsp. suis and B. longum subsp. suillum . Recently, several studies on B. longum suggested the presence of a separate clade containing four strains isolated from infants and one from rhesus macaque. These strains shared a phylogenetic similarity to B. longum subsp. suis DSM 20210 T and B. longum subsp. suillum JCM1995 T [average nucleotide identity (ANI) of 98.1 %) while showed an ANI of 96.5 % with both B. longum subsp. infantis and B. longum subsp. longum . The current work describes five novel additional B. longum strains isolated from Bangladeshi weaning infants and demonstrates their common phylogenetic origin with those of the previously proposed separated clade. Based on polyphasic taxonomic approach comprising loci multilocus sequence analysis and whole genome multilocus sequence typing, all ten examined strains have been confirmed as a distinct lineage within the species B. longum with B. longum subsp. suis and B. longum subsp. suillum as closest subspecies. Interestingly, these strains are present in weaning infants and primates as opposed to their closest relatives which have been typically isolated from pig and calves. These strains, similarly to B. longum subsp. <jats:ext-