Description of Megasphaera jansseni sp. nov., a novel short- and medium-chain fatty acid-producing species isolated from faeces of a wild boar (Sus scrofa), and a taxonomic note on the family Veillonellaceae

A Gram-stain-negative, coccus-shaped, strictly anaerobic strain, named WILCCON 0056 T , was isolated from the faecal sample of a wild boar obtained from Pulau Ubin, Singapore (1.4126° N 103.9577° E). Comparative analyses based on 16S rRNA gene sequence similarity and whole genome relatedness indicated that strain WILCCON 0056 T was most closely related to Megasphaera elsdenii DSM 20460 T , Megasphaera indica NMBHI-10 T and Megasphaera massiliensis DSM 26228 T . However, their average nucleotide identity and digital DNA–DNA hybridization values only ranged from 84.6 to 92.6% and 24.2 to 47.8%, respectively, and were below the 95% and 70% thresholds for species delineation. Substantiated by further physiological, biochemical and comparative genomic analyses, strain WILCCON 0056 T represents a novel species within the genus Megasphaera , for which we propose the name Megasphaera jansseni sp. nov. (type strain WILCCON 0056 T =DSM 118846 T =LMG 33760 T ). The genus Megasphaera belongs to the family Veillonellaceae . Members of this family are commonly found in the gastrointestinal tract of humans and animals and are well known for their ability to produce short-chain fatty acids such as propionic acid and butyric acid. This study further conducted a comprehensive taxonomic reassessment of the family Veillonellaceae . Based on a combination of comparative approaches, we propose reclassification and validation of 14 species within the family Veillonellaceae , refining the family to now comprise 4 validly published genera: Dialister , Megasphaera , Negativicoccus and Veillonella .