Characterizing Microbiota from Sjögren's Syndrome Patients

Abstract

Objective: To compare the oral microbiota of Sjögren's syndrome (SS) with that of healthy subjects (HS).

Methods: Supragingival and subgingival biofilm samples were collected from the mesial-buccal tooth surfaces of SS patients (n = 57) and age- and sex-matched HS (n = 53). Unstimulated saliva and 8 oral tissue samples were taken using a buccal brush. Caries and periodontal measures were recorded. All supragingival samples and a subgroup of 24 SS and 28 HS subgingival samples, as well as 32 SS and 11 HS saliva and oral tissue samples, were analyzed for their content of 41 bacterial species using checkerboard DNA-DNA hybridization. Mean levels (×10⁵ ± SEM) and percentage of DNA probe counts of each species were determined for each sample site and averaged within subjects in the 2 clinical groups. Kruskal-Wallis tests, adjusting for multiple comparisons and cluster analysis, were used for soft tissue and microbial analysis, and the Mann-Whitney test was used to compare caries and periodontal measures.

Results: Mean (×10⁵ ± SEM) total DNA probe counts in supragingival samples were significantly lower (P < 0.001) in the SS (13.3 ± .7) compared to the HS (44.1 ± 6.8) group. In supragingival samples, Veillonella parvula, Fusobacterium nucleatum ss vincenti, and Propionibacterium acnes were markedly elevated in the SS compared to the HS group in both mean (×10⁵ ± SEM) and mean (± SEM) percentage DNA probe counts (P < 0.001). In subgingival samples of SS, V. parvula was significantly different compared to HS (P < 0.05). SS was characterized by high levels of purple and low levels of orange and red complexes. Cluster analysis of oral tissues and saliva demonstrated that the mean microbial profiles for SS patients and the HS group clustered separately. Active root caries (P < 0.003) and attachment loss were significantly higher (P < 0.029) in the SS group compared to the HS group.

Conclusion: These findings indicate that saliva is a major controlling factor of intraoral biofilm. V. parvula may be a unique microbial biomarker for Sjögren's syndrome.

Knowledge transfer statement: The microbiome characterized for Sjögren's syndrome in salivary hypofunction is shown to be under stress and reduced. Veillonella parvula can be a possible identification of a biomarker for Sjögren's syndrome.

Keywords: DNA-DNA hybridization; Veillonella parvula; bulk fluid; mean and percentages of DNA count; plaque; salivary hypofunction.

Figure 1.

Mean ± SEM × 10⁵ probe count of 41 taxa in supragingival plaque samples from 57 Sjögren’s subjects and 53 healthy subjects. Data for each species were averaged within a subject and then across subjects in the 2 clinical groups separately. The significance of differences among groups was sought using the Kruskal-Wallis test and adjusted for multiple comparisons (Socransky et al. 1991). *P < 0.05. **P < 0.01. ***P < 0.001. Species were ordered according to the complexes described by Socransky et al. (1998).

Figure 2.

Mean DNA probe count of 41 taxa in supragingival plaque samples from 57 Sjögren’s subjects and 53 healthy subjects. Data for each species were averaged within a subject and then across subjects in the 2 clinical groups separately. The significance of differences among groups was sought using the Kruskal-Wallis test and adjusted for multiple comparisons (Socransky et al. 1991). *P < 0.05. **P < 0.01. ***P < 0.001. Species were ordered according to the complexes described by Socransky et al. (1998).

Figure 3.

Mean percent DNA probe counts of 40 bacterial species were determined for each sampled site and averaged within each subject for subgingival plaque samples separately.

Figure 4.

Mean count (×10⁵ ± SEM) of 41 microbial species in saliva, dorsal, lateral and ventral tongue, floor of the mouth, buccal mucosa, hard palate, labial vestibule, and attached gingiva.