Eikenella exigua sp. nov., isolated from brain abscess and blood

We herein describe the first novel species within the genus since it was established in 1972 by the reclassification of ' to . From a polymicrobial brain abscess, we encountered an isolate, PXX , that could not validly be named . 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 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 from . Using specific amplification and sequencing of the gene, we further detected the novel species in six historic brain abscesses previously reported to contain based on 16S metagenomics. Out of 24 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 cause endocarditis. The average nucleotide identity value between strain PXX and the type strain ATCC 23834 was 92.1 % and the corresponding genome-to-genome distance value was 47.1 %, both supporting the classification of PXX as a novel species. For this species we propose the name . The type strain of is PXX (DSM 109756 , NCTC 14318 ).