Microbacterium insectihabitans sp. nov., Isolated from Larvae of Allomyrina dichotoma

Two Gram-reaction-positive bacterial strains, designated BWT-B31^T and BWR-S6Y, were isolated from larvae of Allomyrina dichotoma, and their taxonomic positions were examined by a polyphasic approach. Both strains were found to be Gram-reaction-positive, strictly aerobic, short rods and grew at 10-37 °C, pH 5.0-10.0 and in the presence of up to 5% (w/v) NaCl concentration (optimum, 0-1%). Strain BWT-B31^T showed the highest 16S rRNA gene sequence similarity (98.1%) with Microbacterium mangrovi, followed by 97.9% with Microbacterium immunditiarum, while strain BWR-S6Y shared 100% sequence identity with Microbacterium hydrothermale, followed by 99.9% sequence similarity with Microbacterium galbum. In the core genome-based phylogenetic tree, strain BWT-B31^T formed a clade with Microbacterium immunditiarum and Microbacterium mangrovi, with orthologous average nucleotide identities of 81.1% and 76.2%, respectively. Strain BWR-S6Y showed the same topology with that of 16S rRNA gene phylogeny, with an orthologous average nucleotide identity of 96.8% and a digital DNA-DNA hybridization value of 72.0% with Microbacterium hydrothermale. A combination of the phenotypic distinctness and overall genomic relatedness indices supports that strain BWR-S6Y is a strain of Microbacterium hydrothermale, while strain BWT-B31^T represents a new species of the genus Microbacterium, for which the name Microbacterium insectihabitans sp. nov. (type strain, BWT-B31^T = KACC 22261^T = DSM 112528^T = NBRC 115128^T) is proposed.