Prevotella illustrans sp. nov., derived from human oropharyngeal abscess puncture fluid.

An obligately anaerobic strain, designated as A2931T, was isolated from oropharyngeal abscess puncture fluid of a patient sampled during routine care at a hospital and further characterized both phenotypically, biochemically and genotypically. This Gram-negative rod-shaped bacterium was moderately saccharolytic and proteolytic. Phylogenetic analyses of full-length 16S rRNA gene and whole-genome sequences revealed it to be best placed in the genus Prevotella, but to be only comparatively distantly related to recognized species, with the closest relationship to Prevotella baroniae (average nucleotide identity and digital DNA-DNA hybridization values both well below the generally accepted thresholds). Strain A2931T had a genomic DNA G+C content of 47.7 mol%. Its most abundant cellular long-chain fatty acids were anteiso-C15 : 0, iso-C15 : 0 and C16 : 0. Taken together, this polyphasic data suggests strain A2931T to represent a novel species within the genus Prevotella, for which the name Prevotella illustrans sp. nov. is proposed. The type strain is A2931T (=DSM 108028T=CCOS 1232T=CCUG 72806T). Interestingly, we found strain A2931T to correspond to the oral taxon Prevotella HMT-820 in the Human Oral Microbiome Database, as supported by overall genome relatedness index analyses >99 %. Thus, our work not only closes one of the gaps of knowledge about hitherto unnamed species isolated from humans, but also will facilitate identification of this taxon both in the clinical microbiology context and in research alike.

Parvimonas parva sp. nov., derived from a human genito-urinary lesion.

A strain of obligately anaerobically growing Gram-positive cocci was isolated from a human genito-urinary sample and characterized by a polyphasic approach. Analyses of 16S rRNA gene and whole-genome sequences of this strain S3374T indicated that it belonged to the genus Parvimonas. Overall genome relatedness index calculations confirmed it to be phylogenetically distinct from Parvimonas micra (NCTC 11808T) as its most closely related species with standing in nomenclature, with average nucleotide identity and genome-to-genome distance values of 85.8 and 30.2 %, respectively. Biochemically, strain S3374T was strongly proteolytic and can be differentiated from P. micra (DSM 20468T) by absence of phosphatase activity. The DNA G+C content of strain S3374T was 28.6 mol%. Based on the phenotypical, biochemical and genetic findings, strain S3374T is considered to represent a novel species within the genus Parvimonas, for which the name Parvimonas parva sp. nov. is proposed. The type strain is S3374T (=DSM 110786T=CCOS 1934T=CCUG 74294T). This description adds strain S3374T as a second species to the genus Parvimonas which has so far been monotypic. While the type strain of this genus, P. micra, has a long standing in nomenclature and its role in human health and disease has been studied to some extent, this description of the proposed novel species represented by strain S3374T will allow microbiologists worldwide to identify isolates of P. parva sp. nov., a prerequisite for further investigation of its relevance in the clinical context and beyond.