Genus- and species-specific PCR primers for the detection and identification of bifidobacteria

16SrDNA-targeted genus- and species-specific PCR primers have been developed and used for the identification and detection of bifidobacteria. These primers cover all of the described species that inhabit the human gut, or occur in dairy products. Identification of cultured bifidobacteria using PCR primer pairs is rapid and accurate, being based on nucleic acid sequences. Detection of bifidobacteria can be achieved using DNA extracted from human faeces as template in PCR reactions. We have found that, in adult faeces, the Bifidobacterium catenulatum group was the most commonly detected species, followed by Bifidobacterium longum, Bifidobacterium adolescentis, and Bifidobacterium bifidum. In breastfed infants, Bifidobacterium breve was the most frequently detected species, followed by Bifidobacterium infantis, B. longum and B. bifidum. It was notable that the B. catenulatum group was detected with the highest frequency in adults, although it has often been reported that B. adolescentis is the most common species. Real-time, quantitative PCR using primers targeting 16S rDNA shows promise in the enumeration of bifidobacteria in faecal samples. The approach to detect the target bacteria with quantitative PCR described in this review will contribute to future studies of the composition and dynamics of the intestinal microflora.