Evaluation of the PCR method for identification of Bifidobacterium species

AIMS: Bifidobacterium species are known for their beneficial effects on health and their wide use as probiotics. Although various polymerase chain reaction (PCR) methods for the identification of Bifidobacterium species have been published, the reliability of these methods remains open to question. METHODS AND RESULTS: In this study, we evaluated 37 previously reported PCR primer sets designed to amplify 16S rDNA, 23S rDNA, intergenic spacer regions, or repetitive DNA sequences of various Bifidobacterium species. CONCLUSIONS: Ten of 37 experimental primer sets showed specificity for B. adolescentis, B. angulatum, B. pseudocatenulatum, B. breve, B. bifidum, B. longum, B. longum biovar infantis and B. dentium. SIGNIFICANCE AND IMPACT OF THE STUDY: The results suggest that published Bifidobacterium primer sets should be re-evaluated for both reproducibility and specificity for the identification of Bifidobacterium species using PCR. Improvement of existing PCR methods will be needed to facilitate identification of other Bifidobacterium strains, such as B. animalis, B. catenulatum, B. thermophilum and B. subtile.