Occurrence of Bacteroides gingivalis, Bacteroides intermedius and Actinobacillus actinomycetemcomitans in severe periodontitis in relation to age and treatment history.

A total of 242 subjects including 138 untreated severe periodontitis patients and 104 patients with refractory periodontal disease, previously treated for severe periodontitis, were examined for the occurrence of Actinobacillus actinomycetemcomitans, Bacteroides gingivalis and Bacteroides intermedius. Pooled subgingival samples of representative periodontal lesions were used for anaerobic cultivation on blood agar and for the enumeration of A. actinomycetemcomitans on selective TSBV medium. 97% of the untreated patients were infected with one or more of the test micro-organisms. In this patient group, the occurrence of A. actinomycetemcomitans, B. gingivalis and B. intermedius was 54%, 48% and 63%, respectively. The prevalence of A. actinomycetemcomitans positive patients appeared to be age related and decreased with increasing age. Likewise, the number of patients solely infected with A. actinomycetemcomitans decreased with increasing age. The prevalence of B. gingivalis infected patients appeared to increase with increasing age. These phenomena were not observed in the refractory periodontitis patients. The occurrence of A. actinomycetemcomitans, B. gingivalis and B. intermedius in the refractory periodontitis group was 55%, 27% and 59%, respectively. A statistical significant difference in the prevalence of B. gingivalis was found between the untreated and the refractory periodontitis patients. In both patient groups, the relative proportion of A. actinomycetemcomitans was significantly higher in subjects with this bacterium as the sole indicator micro-organism than in patients who, besides being infected with A. actinomycetemcomitans, were also infected with black-pigmented Bacteroides species. Furthermore, in comparison with untreated patients, unsuccessfully treated patients solely infected with A. actinomycetemcomitans had on average a lower number but also a higher mean % of this bacterium.(ABSTRACT TRUNCATED AT 250 WORDS)