The present investigation examined the distribution of 14 subgingival species at a total of 2299 sites in 90 subjects with different levels of periodontal destruction. Subgingival plaque samples taken from the mesial aspect of each tooth were anaerobically dispersed, diluted and plated on non selective media. After anaerobic incubation, colonies were lifted to nylon filters and specific species detected using digoxygenin-labeled whole chromosomal DNA probes. The mean total viable count for all sites in all subjects was 8.3 x 10(6). The probes accounted for an average of 27.8% of the total viable count. The % of subjects in which each species was detected was as follows; V. parvula, 98; B. intermedius I. 98: S. sanguis II, 96; B. intermedius II, 95; C. ochracea, 94; B. gingivalis, 91; S. sanguis I. 85; W. recta, 83; F. nucleatum ss. vincentii, 82; S. intermedius, 80; B. forsythus, 76; P. micros, 74; A. actinomycetemcomitans serotype a, 62 and A. actinomycetemcomitans serotype b, 52. The % of sites colonized by each of the 14 test species varied considerably within different subjects. The median number of sites colonized by different species ranged from 3.6% for A. actinomycetemcomitans serotype b to 43.5% for V. parvula. In half the subjects, the mean % of the total viable counts for each of the test species was < 4%. When subjects were divided on the basis of % of sites at baseline with > 3 mm attachment loss, the 14 probes accounted for 29.9% of the microbiota in the localized disease group and 25% in the widespread disease group. In general, suspected pathogens were slightly higher in the localized disease subjects, but suspected beneficial species were comparable in both groups. Cluster analysis was used to subset subjects on the basis of their mean percentages of the 14 test species. 5 groups were formed with > 60% similarity (Bray-Curtis coefficient) but 21 subjects failed to fit any of the groups. The latter subjects were characterized by low numbers of the test species and were older exhibiting widespread disease and recession.
