Expanding the diversity of Desulfovibrio from the human gut: Desulfovibrio intestinivivus sp. nov., Desulfovibrio desulfopostgatei sp. nov. and Desulfovibrio faecalis sp. nov.

Three strictly anaerobic, Gram-negative, curved rod-shaped bacteria, designated strains QI0430T, QI0434T and QI0442T, were isolated from faecal samples of healthy adult donors in the UK. Phylogenomic analysis based on 31 single-copy marker genes showed that all three isolates formed distinct lineages. Whole-genome average nucleotide identity and digital DNA-DNA hybridization values between each isolate and its nearest phylogenetic neighbours were <95.6 and <63%, respectively, supporting their status as separate species. Genome sizes ranged from 3.41 to 3.59 Mb, with DNA G+C contents of 56.91-57.43 mol%. QI0430 was a non-motile, rod-shaped, catalase-negative bacterium that grew optimally at 37 °C, pH 7.5 and 0% (wt/v) NaCl. QI0434 was a motile, rod-shaped, catalase-negative bacterium that grew optimally at 30 °C, pH 7.0-8.0 and 0-0.9% (wt/v) NaCl. QI0442 was a non-motile, rod-shaped, catalase-negative bacterium that grew optimally at 30-37 °C, pH 9.0 and optimum 0% (wt/v) NaCl. Based on phylogenomic, phenotypic and chemotaxonomic differences, the following three novel species are proposed: Desulfovibrio intestinivivus sp. nov. (type strain QI0430T=DSM 120530=NCIMB 15620T), Desulfovibrio desulfopostgatei sp. nov. (type strain QI0434T=DSM 120532=NCIMB 15621T) and Desulfovibrio faecalis sp. nov. (type strain QI0442T=DSM 120531=NCIMB 15622T).