| Popis: |
We herein describe the first novel species within the genus Eikenella since it was established in 1972 by the reclassification of “Bacteroides corrodens” toEikenella corrodens. From a poly-microbial brain abscess, we encountered an Eikenella isolate PXX that could not validly be namedE. corrodens. The isolate grew on blood agar with small, translucent, pitting colonies after 3 days of anaerobic incubation. By reviewing previously collected invasive isolates, we found an additional Eikenella strain EI_02 from a blood culture exhibiting the same properties as PXX. Phylogenetic analyses based on both whole genome and individual house-keeping genes confirmed that the two strains allocate in a phylogenetic cluster separate fromE. corrodens.Using specific amplification and sequencing of the EikenellanusG-gene as a method, we further detected the novel Eikenella species in six historic brain-abscesses previously reported to containE. corrodensbased on 16S metagenomics. Out of 24 Eikenella whole genome projects available in GenBank, eight cluster together with PXX and EI_02. These isolates were recovered from brain abscess (2), blood (1), bone/soft tissue (3), parotid gland (1) and unknown (1). It remains to be investigated whether the new species can be a cause of endocarditis.The average nucleotide identity (ANI) value between strain PXX and theE. corrodenstype strain ATCC 23834 was 92.1% and the corresponding genome-to-genome distance value 47.1%, both supporting the classification of PXX as a novel species. For this species we propose the nameEikenella exigua. TheE. exiguatype strain is PXXT(DSM 109756T, NCTC 14318T). |
