J Med Microbiol 55 (2006), 109-113; DOI: 10.1099/jmm.0.46280-0
© 2006 Society for General Microbiology
ISSN 0022-2615
Overestimation of Streptococcus mutans prevalence by nested PCR detection of the 16S rRNA gene
Ali Al-Ahmad,
Thorsten Mathias Auschill,
Gabriele Braun,
Elmar Hellwig and
Nicole Birgit Arweiler
Department of Operative Dentistry and Periodontology, Albert Ludwigs University, Hugstetter Strasse 55, D-79106 Freiburg, Germany
Correspondence
Ali Al-Ahmad
ali.al-ahmad{at}uniklinik-freiburg.de
Received 4 August 2005
Accepted 9 September 2005
This study was carried out in order to compare two PCR-based methods in the detection of Streptococcus mutans. The first PCR method was based on primers for the 16S rRNA gene and the second method was based on specific primers that targeted the glucosyltransferase gene (gtfB). Each PCR was performed with eight different streptococci from the viridans group, five other streptococci and 17 different non-streptococcal bacterial strains. Direct use of the S. mutans 16S rRNA gene-specific primers revealed that Streptococcus gordonii and Streptococcus infantis were also detected. After amplifying the 16S rRNA gene with universal primers and subsequently performing nested PCR, the S. mutans-specific nested primers based on the 16S rRNA gene detected all tested streptococci. There was no cross-reaction of the gtfB primers after direct PCR. Our results indicate that direct PCR and nested PCR based on 16S rRNA genes can reveal false-positive results for oral streptococci and lead to an overestimation of the prevalence of S. mutans with regards to its role as the most prevalent causative agent of dental caries.
Copyright © 2006 Society for General Microbiology.
