Jpn. J. Infect. Dis., 65 (5), 415-423, 2012
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Akio Tada1*, Hiroaki Takeuchi2, Hajime Shimizu3, Kenichi Tadokoro3, Kazuya Tanaka3, Katsumi Kawamura3, Toshikazu Yamaguchi3, Toru Egashira3, Yoshiaki Nomura2, and Nobuhiro Hanada2
1Department of Health Science, Hyogo University, Hyogo 675-0195; 2Department of Translational Research, Tsurumi University, School of Dental Medicine, Yokohama, 230-8501; and 3Clinical Genomics Development, BML, Inc., Saitama 350-1101, Japan
(Received February 6, 2012. Accepted July 2, 2012)
*Corresponding author: Mailing address: Department of Health Science, Hyogo University, 2301 Shinzaike Hiraoka-cho, Kakogawa, Hyogo 675-0195, Japan. Tel: +81-79-427-5111, Fax: +81-79-427-5112, E-mail: atada@hyogo-dai.ac.jp.
SUMMARY: When quantifying periodontopathic bacteria, it is important to use a convenient method that does not produce false negative results. The Invader assay is a convenient method because it does not involve gene amplification. The purpose of this study was to evaluate the validity of the Invader assay to quantify periodontopathic bacteria. The Invader technology was applied in quantifying five periodontopathic bacteria (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, and Treponema denticola). The Invader assay produced a linear quantitative detection range over concentrations spanning seven exponential values, with a detection limit of 103.7 copies/tube and intra-day and inter-day variance of 0.1% to 4.7% and 0.1% to 3.4%, respectively, in quantifying five periodontopathic bacteria. We compared the results of the Invader assay with those of real-time polymerase chain reaction (PCR) performed for quantifying five periodontopathic bacteria in 22 patients with periodontitis. Among the Invader-detectable bacterial strains of each species, significant correlations were observed in the counts of concerned bacterial species between these two methods, with correlation coefficients ranging from 0.757 to 0.996. This study validated repeatability and reproducibility of the Invader assay in quantifying periodontopathic bacteria and demonstrated consistent agreement between the Invader assay and real-time PCR in quantifying periodontopathic bacteria.
