New rapid polymerase chain reaction-immunochromatographic assay for Porphyromonas gingivalis.
BACKGROUND
A simple and rapid method for Porphyromonas gingivalis detection in clinical samples has been developed using polymerase chain reaction (PCR) and an immunochromatographic assay (ICA) with a lateral-flow device (strip) to detect species-specific 16S rRNA genes.


METHODS
The PCR used a pair of primer sets labeled with fluorescein isothiocyanate (FITC) or biotin at each 5' terminus. The strip used a nitrocellulose membrane containing streptavidin conjugated to gold particles and anti-FITC line.


RESULTS
PCR and ICA detected as few as 1 and 10 cells of P. gingivalis, respectively. ICA required 5 to 10 minutes more than the initial PCR. The amplifications were not observed in other oral black-pigmented bacteria at concentrations of 10(6) colony forming unit (CFU). The ICA strips showed bands at more than 10(4) CFU/ml equivalents in clinical samples from periodontitis.


CONCLUSIONS
A diagnostic assay based on PCR-ICA was developed for the detection of P. gingivalis, and results were obtained visually in 3 hours. PCR-ICA will be a valuable tool for the rapid detection of target bacteria by chair side.
Takada
Kazuko
K
Department of Microbiology, Nihon University School of Dentistry at Matsudo, Japan.
Sakaguchi
Yoshiaki
Y
Oka
Chitoshi
C
Hirasawa
Masatomo
M
D015373:Bacterial Typing Techniques; D002845:Chromatography / Q000379:methods; D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000032:analysis; D005883:Gingival Crevicular Fluid / Q000382:microbiology*; D006801:Humans; D010518:Periodontitis / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000379:methods*; D016966:Porphyromonas gingivalis / Q000235:genetics / Q000302:isolation & purification*; D012680:Sensitivity and Specificity
D004269:DNA, Bacterial