Brevilactibacter coleopterorum sp. nov., isolated from the intestine of the dark diving beetle Hydrophilus acuminatus, and Weissella coleopterorum sp. nov., isolated from the intestine of the diving beetle Cybister lewisianus

A polyphasic taxonomic approach was used to characterize two novel bacterial strains, designated as HDW11(T) and HDW19(T), isolated from intestine samples of the dark diving beetle Hydrophilus acuminatus and the diving beetle Cybister lewisianus, respectively. Both isolates were Gram-stain-positive, facultatively anaerobic and non-motile. Strain HDW11(T) grew optimally at 30 degrees C, pH 8 and in the presence of 1% (w/v) NaCl. Strain HDW19T grew optimally at 25 degrees C, pH 7 and in the presence of 0.3% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences and genome sequences revealed that strain HDW11(T) is a member of the genus Brevilactibacter and is closely related to Brevilactibacter flavus VG341(T) [with 97.9% 16S rRNA sequence identity and 79.1% average nucleotide identity (ANI)], and that strain HDW19(T) belongs to the genus Weissella and is closely related to W. koreensis KCTC 3621(T) (with 98.9% 16S rRNA sequence identity and 79.5% ANI). The major cellular fatty acids of strains HDW11(T) and HDW19(T) were C-18:1 omega 9c and anteiso-C-15:0, respectively. The sole respiratory quinone of strain HDW11(T) was MK-9 (H-4). The major polar lipid components of strain HDW11(T) were diphosphatidylglycerol and phosphatidylglycerol, and the major polar lipid component of strain HDW19(T) was diphosphatidylglycerol. The genomic DNA G+C content of strains HDW11(T) and HDW19(T) were 72.1 and 37.2 mol%, respectively. The results of phylogenetic, phenotypic, chemotaxonomic and genotypic analyses suggest that strain HDW11(T) represents a novel species within the genus Brevilactibacter, and that strain HDW19(T) represents a novel species within the genus Weissella. We propose the name Brevilactibacter coleopterorum sp. nov. for strain HDW11(T) (=KACC 21335(T)=KCTC 49320(T)=JCM 33680(T)) and the name Weissella coleopterorum for strain HDW19(T) (=KACC 21347(T)=KCTC 43114(T)=JCM 33684(T)).

Automated summary

A polyphasic taxonomic approach was used to characterize two novel bacterial strains isolated from dark diving beetles in this study. Phylogenetic, phenotypic, chemotaxonomic, and genotypic analyses led to the proposal of two new species within the genera Brevilactibacter and Weissella, respectively, with detailed descriptions of their characteristics and taxonomy.