Identification and Characterization of Bifidobacterium asteroides Isolates

Two bacterial isolates named BA15 and BA17, previously obtained from honeybee gut and subjected to morphological characterization (unpublished data), were analyzed for physiological and biochemical properties (catalase, oxidase, spore formation, gelatinase activities, production of indole, NH₃ from arginine and CO₂ from glucose) and with the use of the API rapid ID 32 A kit (BioMérieux, Grassina, Italy). Based on the enzymatic profile, typical of the Bifidobacterium genus, both isolates were identified at species level. The total genomic DNA was extracted following the method previously described [28 (link)] and 16S rDNA was amplified using the primer pairs Bif164 and Bif662 [29 (link),30 (link)]. PCR products were purified using a Qiaquick PCR purification kit (Qiagen Hilden, Germany) and subjected to 16S rDNA sequencing. Comparison with sequences held in the BLAST database allowed both stains to be ascribed to the Bifidobacterium asteroides species. The accession numbers of the sequenced strains were as follows (code and identity percentage of isolates in parentheses): Bifidobacterium asteroides MG650026.1 (BA15, 99.60%) and Bifidobacterium asteroides CP017696.1 (BA17, 99.41%).