Contributors to the Abundance of Biofilm-Detached Bacteria in Periodontitis

Objectives:
Subgingival biofilm is the expected origin of bacteria in gingival crevicular fluid (GCF). Abundance of certain species in GCF may be attributed to their detachment preference from subgingival biofilm. Our aim was to investigate which bacterial and host variables contribute to the abundance of a group of periodontitis-associated bacteria in GCF.
Methods:
Systemic and periodontal variables were collected from 17 periodontitis patients. GCF samples were obtained using filter-paper strips and subgingival samples using paper points. HOMIM, a 16S rRNA gene microarray, was used for microbial analysis. Bacterial variables included individual species/taxa but also a group-variable for 10 periodontitis-associated species (PER). Conventional statistics and multivariate orthogonal projections to latent structures (OPLS) were used for data analysis.
Results: OPLS regression analysis showed that among species found in subgingival samples Leptotrichia hofstadii and Tannerella HOT286 were the strongest contributors to the abundance and Peptostreptococcus stomatis to the %abundance of PER group in GCF. Regarding species found in GCF samples, Dialister invisus was the strongest contributor to the abundance and Campylobacter rectus/Campylobacter concisus to the %abundance of PER group in GCF. Age correlated negatively while both proportion of sites with advanced periodontitis and number of teeth with initial periodontitis correlated positively to the %abundance of PER in GCF. OPLS dendrogram divided patients into 3 groups, which differed with regard to richness, abundance and %abundance of PER, blood leukocyte count, number of extracted teeth, number of teeth with initial periodontitis and plaque.
Conclusions: It appeared that with increasing age, taxa other than PER elevate their abundance in GCF and that the higher the severity and extent of periodontal destruction the higher is the abundance of PER in GCF. Furthermore, subgingival L. hofstadii, Tannerella HOT286, and P. stomatis may act as indicators or promoters for increased detachment of periodontitis-associated bacteria from the subgingival biofilm.