Niabella hirudinis and Niabella drilacis sp. nov., isolated from the medicinal leech Hirudo verbana

Abstract

Two Gram-negative, rod-shaped bacteria, strains E96T and E90T, were isolated from medicinal leeches (Hirudo verbana) and characterized by a polyphasic taxonomic approach. Phylogenetic analysis based on the nearly full-length 16S rRNA gene sequence showed that the two strains shared 98.1 % sequence similarity and were affiliated with the genus Niabella within the phylum Bacteroidetes , with 94.4–97.6 % sequence similarity to type strains of species of the genus Niabella and highest sequence similarity to the type strain of Niabella aurantiaca (97.3 and 97.6 %, respectively). Niabella -related 16S rRNA gene sequences were recently detected in the bladders of Hirudo verbana; however, no cultured representatives were so far available. Genomic fingerprint analysis using repetitive element primed (rep)- and randomly amplified polymorphic DNA (RAPD)-PCRs and DNA–DNA hybridization experiments clearly showed that the strains were different from each other (DNA–DNA relatedness values of 39.1 %, reciprocal 28.0 %) and from the type strains of N. aurantiaca (<19.7 %) and Niabella tibetensis (<41.1 %). Chemotaxonomic analyses confirmed the affiliation to the genus Niabella . Both strains contained MK-7 as the predominant menaquinone. The major fatty acids of both strains were iso-C15 : 0, iso-C15 : 1 G, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH), which is characteristic for the genus Niabella . Based on genotypic, chemotaxonomic and physiological characterization, we propose two novel species of the genus Niabella , Niabella hirudinis sp. nov., with strain E96T ( = DSM 25812T = CCM 8411T = LMG 26956T) as the type strain, and Niabella drilacis sp. nov., with strain E90T ( = DSM 25811T = CCM 8410T = LMG 26954T) as the type strain.