Megasphaera stantonii sp. nov., a butyrate-producing bacterium isolated from the cecum of a healthy chicken.

A novel mesophilic, anaerobic, Gram-stain-negative bacterium was isolated from the cecum of a healthy white leghorn chicken, and designated AJH120T. Cells were coccoid or diplococcoid with an average size of 0.8-1.8 µm and were non-motile with no evidence of spores. Phylogenetic analysis of 16S rRNA gene sequences revealed this organism to be a member of the genus Megasphaera, with the closest relatives being Megasphaera elsdenii (95 % sequence identity) and Megasphaera cerevisiae (95 % sequence identity). Growth was observed between 30 and 50 °C and between pH 5.0 and 9.0. AJH120T utilized a variety of carbon sources, including succinate, gluconate, fructose, ribose and pyruvate, as well as many individual amino acids. The DNA G+C content for the genome sequence of AJH120T was 52.1 mol%. Digital DNA-DNA hybridization (dDDH), average nucleotide identity (ANI) and average amino acid identity (AAI) between AJH120T and close taxonomic relatives, indicated divergence consistent with the strain representing a novel species. The major fatty acid methyl esters of the organism were C12 : 0, C14 : 0 3-OH, C18 : 1ω9c, C16 : 0 and C16 : 1ω9c. AJH120T was able to produce several short chain fatty acids, including butyrate, acetate, propionate and isovalerate. Together, these data indicate that AJH120T represents a novel species within the genus Megasphaera. We propose the name Megasphaerastantonii sp. nov. for the species. The type strain of this species is AJH120T (=DSM 106750T=CCUG 71842T).