Multiplex PCR using conserved and species-specific 16S rDNA primers for simultaneous detection of Fusobacterium nucleatum and Actinobacillus actinomycetemcomitans

This study was undertaken to develop PCR primers for the simultaneous detection of Fusobacterium nucleatum and Actinobacillus actinomycetemcomitans, using two species-specific reverse primers in combination with a single conserved forward primer. These primers target the variable and conserved regions of the 16S rDNA. The primer specificity was tested against (i) four E nucleatum and three A. actinomycetemcomitans strains and (ii) seven representatives of the different species of oral bacteria. The primer sensitivity was determined by testing serial dilutions of the purified genomic DNA of F nucleatum and A. actinomycetemcomitans. The data indicate that species-specific amplicons could be obtained for all the E nucleation and A. actinomycetemcomitans strains tested, which were not found in the seven other species. The multiplex PCR could detect as little as 4 fg of chromosomal DNA of F nucleatum and A. actinomycetemcomitans simultaneously. These findings suggest that these PCR primers are highly sensitive and are suitable for applications in epidemiological studies, diagnosis, and monitoring F nucleatum and A. actinomycetemcomitans after the treatment of periodontitis.