Description of Eikenella halliae sp. nov. and Eikenella longinqua sp. nov., derived from human clinical materials, emendation of Eikenella exigua Stormo et al. 2019 and emendation of the genus Eikenella to include species which are strict anaerobes

• Published in: International journal of systematic and evolutionary microbiology Vol. 70; no. 5; pp. 3167 - 3178
• Main Authors: Bernard, Kathryn A, Burdz, Tamara, Wiebe, Deborah, Bernier, Anne-Marie
• Format: Journal Article
• Language: English
• Published: England 01-05-2020
• Subjects: whole genome sequencing; Canadian Eikenella exigua; Eikenella longinqua; Eikenella halliae; facultative or strictly anaerobic; HACEK
• ISSN: 1466-5026; 1466-5034
• DOI: 10.1099/ijsem.0.004150

The
(HACEK) group genus
contained a single species,
for many years. In November 2019,
was described after recovery from a brain abscess and blood culture in Norway. Coincidentally, characterization of 22 Gram-negative bacteria resembling
from 17 Canadian patients had been underway. Seven isolates from five patients were conclusively identifiable as
. One (NML 120819) was deemed to represent a species of the genus
most closely related to
. Fourteen isolates had 97.6 to 98.8% similarities to
by 16S rRNA gene sequencing, forming three distinct groups by genome analyses. The largest contained ten anaerobic isolates from eight patients recovered from blood, brain, bone and other abscesses; upon re-evaluation, this group was found to be most consistent with
. A second facultatively anaerobic clade consisted of two ocular isolates from one patient and a sinus isolate from a second patient. The third taxon consisted of a single strictly anaerobic blood culture isolate. The novel taxa, like
, were poorly reactive biochemically and difficult to discern from each other phenotypically and chemotaxonomically, including by cellular fatty acids. MALDI-TOF (Bruker) and whole-genome sequencing were used to further characterize isolates. Draft genomes for the strains had similar DNA G+C contents (55.38-58.53 mol%) while sizes varied from 1.82 Mb to 2.54 Mb. We propose here emendations of the genus
and the species
, as well as describing
sp. nov. NML 130454
(=LMG 30894
=NCTC 14180
) and
sp. nov. NML 02-A-017
(=LMG 30896
=NCTC 14179
), on the basis of these findings.