Development and application of tuf gene-based PCR and PCR-DGGE methods for the detection of 16 Bifidobacterium species

A total of 16 Bifidobacterium species were assayed by polymerase chain reaction (PCR) and PCR–denaturing gradient gel electrophoresis (PCR–DGGE) methods targeted on a 770-bp region of the tuf gene. Based on this sequence, a genus-specific primer set and 12 primer sets for 12 Bifidobacterium species including those previously reported for six probiotic species were developed. On the other hand, when these 16 Bifidobacterium species were subjected to PCR–DGGE analysis, 13 product migration patterns were obtained. PCR products for strains in pairs of B. adolescentis/B. thermophilum, B. longum/B. magnum and B. lactis/B. gallinarum migrated the same distance on the DGGE gel. Combined with species-specific PCR primers specific to B. adolescentis, B. longum and B. lactis, all of the 16 Bifidobacterium species could be identified. In addition, the subspecies of B. animalis, i.e., B. animalis and B. lactis, could be discriminated. This study indicated that the tuf gene is highly useful for the molecular detection of different Bifidobacterium species. Using the PCR and PCR–DGGE methods, 16 Bifidobacterium species, including those from probiotic products and those from other origins, could be rapidly identified.