Escherichia marmotae sp. nov., isolated from faeces of Marmota himalayana

Abstract

The taxonomic position of a group of seven closely related lactose-negative enterobacterial strains, which were isolated from fresh faecal samples of Marmota himalayana collected from the Qinghai-Tibetan plateau, China, was determined by using a polyphasic approach. Cells were Gram-reaction-negative, non-sporulating, non-motile, short rods (0.5–1 × 1–2.5 μm). By 16S rRNA gene sequences, the representative strain, HT073016T, showed highest similarity values with Escherichia fergusonii ATCC 35469T at 99.3 %, Escherichia coli ATCC 11775T at 99.2 %, Escherichia albertii LMG 20976T at 98.9 %, Escherichia hermannii CIP 103176T at 98.4 %, and Escherichia vulneris ATCC 33821T at 97.7 %. Phylogenetic analysis based on the 16S rRNA gene sequences showed that the seven strains formed a monophyletic group with five other species of the genus Escherichia. Digital DNA–DNA hybridization studies between strain HT073016T and five other species of the genus Escherichia showed that it shared less than 70 % DNA–DNA relatedness with all known species of the genus Escherichia, supporting the novel species status of the strain. The DNA G+C content of strain HT073016T was 53.8 mol%. On the basis of phenotypic and phylogenetic characteristics, strain HT073016T and the six other HT073016T-like strains were clearly distinct from the type strains of other recognized species of the genus Escherichia and represent a novel species of the genus Escherichia, for which the name Escherichia marmotae sp. nov. is proposed, with HT073016T ( = CGMCC 1.12862T = DSM 28771T) as the type strain.