Periodontal bacterial species and target serotypes in individuals harboring Aggregatibacter actinomycetemcomitans: a retrospective study in a large Brazilian population

OBJECTIVE: The first aim of this study was to evaluate the prevalence of A. actinomycetemcomitans in a large Brazilian population. The second aim was to analyse the frequency of A. actinomycetemcomitans serotypes, P. gingivalis, P. intermedia, T. forsythia and C. rectus in the positive individuals for A. actinomycetemcomitans. MATERIAL AND METHODS: The population was composed of 1,320 individuals. Subgingival biofilm samples were taken for molecular analysis. RESULTS: It was revealed that 263 (19.9%) individuals tested positive for A. actinomycetemcomitans. Then, the genomic DNA of A. actinomycetemcomitans serotypes (a to f ) as well as P. gingivalis, P. intermedia, T. forsythia, and C. rectus were analysed. A. actinomycetemcomitans serotype a was detected in 28.5%, serotype b in 15.97%, serotype c in 51.71%, and serotype e in 3.80% of individuals, respectively. Serotypes d and f were not detected. The frequency of A. actinomycetemcomitans serotype a was significantly higher in C. rectus-positive individuals than in P. gingivalis-, P. intermedia-, or T. forsythia-positive individuals. Additionally, the frequency of serotypes b and c were significantly higher in both C. rectus- and T. forsythia-positive individuals in comparison to P. gingivalis- and P. intermedia-positive individuals. Meanwhile, the frequency of serotype e was not associated with the presence of the other periodontal pathogens. CONCLUSION: The data of this large population confirmed A. actinomycetemcomitans prevalence values previously observed in smaller groups. Further, suggested potential coaggregation among selected A. actinomycetemcomitans serotypes and other target periodontal bacterial species in the subgingival environment.