Eikenella glucosivorans sp. nov., isolated from a human throat swab, and emendation of the genus Eikenella to include saccharolytic species

Abstract

A novel species within the genus <i>Eikenella</i> is described, based on the phenotypical, biochemical and genetic characterization of a strain of a facultatively anaerobic, Gram-negative rod-shaped bacterium. Strain S3360^T was isolated from the throat swab of a patient sampled during routine care at a hospital. Phylogenetic analyses (full-length 16S rRNA gene and whole-genome sequences) placed the strain in the genus <i>Eikenella</i>, separate from all recognized species but with the closest relationship to <i>Eikenella longinqua</i> (NML 02-A-017^T). <i>Eikenella</i> is one of the genera in the HACEK group known to be responsible for rare cases of endocarditis in humans. Until the recent descriptions of <i>Eikenella exigua</i>, <i>Eikenella halliae</i> and <i>Eikenella longinqua</i>, <i>Eikenella corrodens</i> had been the only validly published species in this genus since its description as <i>Bacteroides corrodens</i> in 1958. Unlike these species, strain S3360^T is able to metabolize carbohydrates (glucose). The average nucleotide identities of strain S3360^T with <i>E. longinqua</i> (NML 02-A-017^T) and <i>E. corrodens</i> (NCTC 10596^T), the type species of the genus, were 90.5 and 84.7 %, respectively, and the corresponding genome-to-genome distance values were 41.3 and 29.0 %, respectively. The DNA G+C content of strain S3360^T was 58.4 mol%. Based on the phenotypical, biochemical and genetic findings, strain S3360^T is considered to represent a novel species within the genus <i>Eikenella</i>, for which the name <i>Eikenella glucosivorans</i> sp. nov. is proposed. The type strain is S3360^T (DSM 110714^T=CCOS 1935^T=CCUG 74293^T). In addition, an emendation of the genus <i>Eikenella</i> is proposed to include species which are saccharolytic.