Sulfate-reducing bacteria in relation with other potential periodontal pathogens

Background, aims: Oral sulfate-reducing bacteria are involved in several cl inical categories of periodontitis. The aim of this cross-sectional study w as to compare the presence of sulfate-reducing bacteria (SRB) with other pu tative pathogens including spirochetes, Actinobacillus actinomycetemcomitan s, Bacteroldes forsythus, Porphyromonas gingivalis, and Treponema denticola in periodontal lesions. Method: Periodontal SRB were detected by enrichment culture and compared wi th a microscopic spirochete count (n=168). Species-specific oligonucleotide probes directed against the 16S rRNA were employed to determine the presen ce of A. aetinomycetemncomitans, P. gingivalis, B. forsythus, and T. dentic ola (n=55). Results: A significant positive correlation was observed between the presen ce of SRB and the proportions of spirochetes in subgingival plaque, althoug h the 2 bacterial groups also occurred separately. SRB tended to be negativ ely correlated with the presence of A. actinonzycetemcomitans. In contrast, all pockets with SRB harbored either T. denticola, or both T denticola and B. forsythus (12/14) before therapy. Interestingly, the combination of SRB with P. gingivalis occurred in 32% of the periodontal pockets before treat ment. After initial periodontal therapy, the prevalence of this combination was reduced to 2% of the sites, and to 25% of the sites in recall patients . Conclusion: The presence of SRB was positively correlated with T. denticola , B. forsythus, and P. gingivalis in periodontal lesions. These suspected p athogens form a complex strongly associated with destructive periodontitis.