Intestinimonas butyriciproducens gen. nov., sp. nov., a novel butyrate-producing bacterium from the mouse intestine

Whilst creating a bacterial collection of strains from the mouse intestine, we isolated a Gram-negative, spore-forming, non-motile and strictly anaerobic rod-shaped bacterium from the caecal content of a TNFdeltaARE mouse. The isolate, referred to as strain SRB-521-5-IT, was originally cultured on a reduced agar medium containing yeast extract, rumen fluid and lactic acid as energy and carbon sources. Phylogenetic analysis of partial 16S rRNA genes revealed that the species most closely related to strain SRB-521-5-IT (GenBank accession no. KC311367) were Flavonifractor plautii and Pseudoflavonifractor capillosus (<95 % sequence identity; 1436 bp). In contrast to F. plautii and P. capillosus, strain SRB-521-5-IT contained a substantial amount of C18:0 dimethylacetal. Additional major fatty acids were C14:0 methyl ester, C16:0 dimethylacetal and C18:0 aldehyde. Strain SRB-521-5-IT differed in its enzymatic profile from F. plautii and P. capillosus by being positive for dextrin, maltotriose, turanose, D,L-lactic acid and D-lactic acid methyl ester but negative for D-fructose. In reduced Wilkins-Chalgren-Anaerobe broth, strain SRB-521-5-IT produced approximately 8 mM butyrate and 4 mM acetate. In contrast to F. plautii, the strain did not metabolize flavonoids. It shows intermediate resistance towards the antibiotics ciprofloxacin, colistin and tetracycline. Based on genotypic and phenotypic characteristics, we propose to create the name Intestinimonas butyriciproducens gen. nov., sp. nov. to accommodate strain SRB-521-5-IT (= DSM 26588T = CCUG 63529T)