DETECTION OF PORPHYROMONAS-GINGIVALIS IN GINGIVAL EXUDATE BY A DIPEPTIDE ENHANCED TRYPSIN-LIKE ACTIVITY

PORPHYROMONAS GINGIVALIS IN SUBGINGIVAL PLAQUE is an important risk fa ctor for future periodontal attachment loss in susceptible adults. The elimination of P. gingivalis is usually concomitant with a healing pr ocess. Therefore, it should be valuable to have an easy chairside meth od to follow the effect of periodontal treatment on P. gingivalis dete ction as well as on its eventual reappearance during the maintenance p eriod. We have previously reported the stimulation of amidolytic activ ity of P. gingivalis by the addition of glycyl-glycine to the assay bu ffer. In this study we determined the proportions of P. gingivalis, Pr evotella intermedia, Actinobacillus actinomycetemcomitans, Fuso-bacter ium nucleatum, Capnocytophaga spp, Camphylobacter rectus, and Eikenell a corrodens by cultivation technique and the amidolytic activity, usin g N-benzoyl-L-arginine-p-nitroanilide (BAPNA) as substrate, in gingiva l exudate before and during a 3-year treatment and maintenance period. P. gingivalis was the only species yielding a high and persistent cor relation to stimulated amidolytic activity (P values less than or equa l to 0.0001) on both site (r=0.5) and subject (r=0.8) level. Testing p ure cultures of suggested periodontal pathogens for effect of glycyl-g lycine on amidolytic activity, we found that of P. gingivalis to be 5. 9-fold increased. The amidolytic activity of Treponema denticola was o nly slightly stimulated (ratio with/without glycyl-glycine=1.2) and th at of Capnocytophaga slightly inhibited (ratio with/without glycyl-gly cine=0.8). The outcome of this study has the potential to be used for the development of a simple, rapid, and inexpensive assay for a qualit ative and quantitative determination of P. gingivalis in gingival crev icular fluid.