[Identification of Bifidobacterium strains isolated from fecal samples of some Iranian subjects using 16 SrRNA gene sequence analysis and PCR-based gene specific primers]

For the first time in Iran 40 strains of Bifidobacterium were isolated from feces of Iranian subjects. By using phenotypic tests, 18 isolates were identified as Bifidobacterium longum, 10 as Bifidobacterium bifidum and one as Bifidobacterium catenolatum. In order to validate these results and also to identify other isolates that had not been identified by phenotypic tests, two methods of PCR with genus-specific primers of Bif164f and Bif601r and 16SrRNA gene sequence analysis were applied. Results of PCR confirmed the obtained phenotypic identifications. Moreover by this method the 8 remaining strains were identified as Bifidobacterium species. Using sequencing 16 SrRNA gene, 5 B. longum strains were identified that had different fermentation pattern from B. longum. Some new ribose negative Bifidobacterium longum strains were also identified. The obtained results present new strains of Bifidobacterium longum