Veillonella faecalis sp. nov., a propionic acid-producing bacterium isolated from the faeces of an infant

A strictly anaerobic, Gram-stain-negative, catalase-negative, cocci-shaped, and propionate-producing bacterial strain, named Ds1651^T was isolated from the fecal sample collected from a South Korean infant. Through a comparison of 16S rRNA gene sequences, it was revealed that Ds1651^T had the highest phylogenetic affinity with Veillonella nakazawae KCTC 25297 ^T (99.86%), followed by Veillonella infantium KCTC 25370 ^T (99.80%), and Veillonella dispar KCTC 25309 ^T (99.73%) in the family Veillonellaceae. Average nucleotide identity values between Ds1651^T and three reference species were 95.48% for Veillonella nakazawae KCTC 25297 ^T, 94.46% for Veillonella infantium KCTC 25370 ^T, and 92.81% for Veillonella dispar KCTC 25309 ^T. The G + C content of Ds1651^T was 38.58 mol%. Major fermentation end-products were acetic and propionic acids in Trypticase peptone glucose yeast extract broth with 1% (v/v) sodium lactate. The predominant cellular fatty acids that account for more than 10% were summed in Feature 8 (C_17:1 ω8c and/or C_17:2) and C_13:0. Based on the findings from phylogenetic, genomic, phenotypic, and chemotaxonomic studies, we propose that the type strain Ds1651^T (= KCTC 25477 ^T = GDMCC 1.3707 ^T) represents a novel bacterial species within the genus Veillonella, with the proposed name Veillonella faecalis sp. nov.