Actinobacillus actinomycetemcomitans in Brazilian insulin-dependent individuals with diabetes mellitus.

The prevalence of Actinobacillus actinomycetemcomitans (Aa) in subgingival plaque specimens from 26 insulin-dependent diabetes mellitus patients, 11-25 years of age, was determined between January 1987 and December 1989. One hundred and thirty subgingival plaque samples were collected with sterile periodontal curettes. The specimens were weighted, diluted, inoculated on trypticase-soy-serum-bacitracin-vancomycin agar medium (TSBV) and incubated under microacrophilic conditions. Aa was isolated from 2.3% of healthy periodontal areas in these patients, while the microorganism was found in 12.5% of the sites with gingivitis and in 2.6% of the periodontal pockets examined. Although biochemical tests used for the characterization of Aa strains showed homogeneous results, different biotypes were isolated from one or more periodontal sites in the same patient.