Prevotella intermedia and Prevotella nigrescens serotypes, ribotypes and binding characteristics.

Type strains and 62 clinical isolates of Prevotella intermedia and Prevotella nigrescens were typed with the use of genomic DNA fingerprints and rRNA gene probes. The strains were further serotyped with monoclonal antibodies and characterized with SDS-PAGE, enzymatic activities, hemolysis and hemagglutination and coaggregation with Streptococcus and Actinomyces spp. P. intermedia and P. nigrescens were found to have distinct ribotype patterns which correspond to previously defined serotyupes I and II/III, respectively. No clear phenotypic difference related to hemolysis, hemagglutination and coaggregation with streptococcus and actinomyces species, or expression of aminopeptides and lipase was found between P. intermedia and P. migrescens.

Periodontopathogens in elderly Chinese with different periodontal disease experience.

If an etiological relationship exists between destructive periodontal disease and putative periodontopathogens, they would be expected to have a very low prevalence in periodontally healthy elderly persons. To test this hypothesis, 2 subgroups of elderly, rural Chinese (a periodontally "best" and a "worst" group, each comprising 15 persons) were identified in 1990 from a cohort aged 55-69 years, examined in 1984. Assessment of changes in periodontal status over the 6-year period were possible by comparing detailed clinical recordings performed by the same examinator. Subgingival microbial samples were taken at the mesial aspects of an upper central incisor and a lower canine and examined for the presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia group, Prevotella melaninogenica group, Capnocytophaga, Selenomonas, Campylobacter rectus as well as predominant Streptococcus and Actinomyces species. During the 6 years prior to microbiological sampling, persons in the "best" group had lost an average of 1.21 +/- 0.48 mm attachment, while persons in the "worst" group had lost an average of 1.60 +/- 0.94 mm. The latter group had lost 53.3 teeth, predominantly for periodontal reasons, in contrast to 1.8 teeth lost in the "best" group. "Best" persons did not differ from "worst" persons with respect to the occurrence of the putative periopathogens, total viable count, and total streptococcal and Actinomyces recovery. Similarly, sites which had experienced an attachment loss > or = 2 mm during the 6-year period did not differ microbiologically from sites with less attachment loss. It is concluded that subgingival microbial characterization does not allow for a distinction between elderly individuals with markedly different periodontal disease experiences.

Effect of treatment on some periodontopathogens and their antibody levels in periodontal abscesses.

Twenty patients suffering from abscess of periodontal origin were treated and followed clinically and microbiologically for 6 months. Microbiological examination was performed by culture technique. One deep and one shallow periodontal pocket in the same patient were examined concomitantly. Serum was collected and analyzed for specific antibody level using ELISA methodology. Treatment included supragingival scaling, drainage, and irrigation of the periodontal pocket with 0.85% sodium chloride and systemic tetracycline administration, 1 g per day for 2 weeks. At baseline, 90% of the abscesses harbored Porphyromonas gingivalis and/or Prevotella intermedia. After 6 months, abscess sites demonstrated a reduced probing depth, less bleeding on probing, and gain of attachment. Abscess sites showed no P. gingivalis and the proportion of P. intermedia was significantly reduced 6 months after treatment. In deep periodontal pockets a similar pattern was seen. Shallow pockets demonstrated few clinical signs of inflammation and the number of bacteria was generally low. Campylobacter rectus, Capnocytophaga spp, and Fusobacterium nucleatum were frequently seen in low numbers in most sites during the study period, while Actinobacillus actinomycetemcomitans was detected only in a few sites. The IgG levels in patient sera against antigens of homologous bacterial strains remained fairly constant for 6 months. The result of the present study indicates that P. gingivalis and P. intermedia are involved in periodontal abscess formation. Also, treatment where drainage is combined with tetracycline administration promotes healing and reattachment.

Black-pigmented gram-negative anaerobes in periodontitis.

Black-pigmented Gram-negative anaerobes have been associated with periodontal disease and tooth loss since they were first isolated by Burdon in 1928. Porphyromonas gingivalis, which is usually not isolated from children, adolescents or adults with no periodontal breakdown, has been recognized as one of the most important periodontopathogens. Its presence is strongly correlated with deep periodontal pockets, which are assumed to be its main habitat. Correlations have been shown also with attachment loss, clinical inflammation and serum antibody levels, indicating an aetiological role in the periodontal disease. Their pathogenicity in animal models resembling periodontal disease is documented. They are frequently isolated from periodontal abscesses. The relationship between Prevotella intermedia and periodontal disease is not clear. It is frequently isolated from advanced periodontitis, often as the only black-pigmented Gram-negative anaerobic species; however, the prevalence in adults with no periodontal breakdown is high. It is found frequently in periodontal abscesses and in acute necrotizing and ulcerative gingivitis. Serogroup I is found predominantly in deep periodontal pockets, whereas all serogroups (I-III) are found in shallow pockets and gingivitis. No conclusive difference in pathogenicity between serogroups has been found. Pr. melaninogenica, Pr. denticola and Pr. loescheii are frequently found in the gingival crevice in preschool children and other age groups with gingivitis, but are seldom found in deep periodontal pockets.