DIRECT-DETECTION OF PORPHYROMONAS-GINGIVALIS IN MACACA-FASCICULARIS DENTAL PLAQUE SAMPLES USING AN OLIGONUCLEOTIDE PROBE

OLIGONUCLEOTIDE PROBES COMPLEMENTARY to the hypervariable regions of t he 16S rRNA of Polphyromonas gingivalis, and previously shown to speci fically identify human P. gingivalis strains to the species level, wer e tested for their ability to recognize P gingivalis from nonhuman pri mates (Macaca fascicularis), either as distinct isolates or in subging ival dental plaque. The P-32-labeled probes hybridized with all 147 mo nkey isolates identified as P. gingivalis by morphology and biochemist ry, but did not hybridize with any of the 331 isolates representing 17 genera of bacteria unrelated to P gingivalis, or to the more closely related P. endodontalis and P. asaccharolytica. This corresponds to se nsitivities and specificities of 100%. Of 76 M. fascicularis plaque sa mples, P gingivalis was detected by probe and culture in 67. Of 26 hum an plaque samples taken from separate individuals free of periodontal disease, 23 failed to demonstrate P. gingivalis by probe or culture. T he results of the combined 102 monkey and human plaque samples indicat e that, when compared to culture as the ''gold standard,'' the P gingi valis probe had a sensitivity of 96%, a specificity of 87%, and an ove rall agreement with culture of 93%. These results reveal that the olig onucleotide probes used to identify P. gingivalis are specific for thi s organism, and give results comparable to culture methods for detecti ng the presence of P. gingivalis in M. fascicularis dental plaque.