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: このメールアドレスはスパムボットから保護されています。閲覧するにはJavaScriptを有効にする必要があります。.

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 10^3.7 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.