Pre-Term Birth Impacts the Subgingival Microbiome and Salivary Immunological Parameters

Objectives: Periodontal diseases have been associated with adverse pregnancy outcomes, including pre-term birth. It is unclear whether the link is bidirectional or follows a microbiological or immunological mechanism. In this study, we evaluated the subgingival microbiome and salivary markers of inflammation in mothers who had pre-term birth.
Methods: In this case-control study, 17 pre-term and 17 on-term mothers were assessed up to 10 days after delivery. Visible plaque index (PI), bleeding on probing (BOP), probing depth (PD) and clinical attachment level (CAL) were measured. Six subgingival biofilm samples were collected, from shallow (PD<5 mm) and deep pockets (PD≥5 mm) in each patient, and analyzed by checkerboard DNA–DNA hybridization. Saliva samples were analyzed by a multiplex assay to determine the levels of pro-inflammatory cytokines (MCP-1; IP-10; EGF; IL-1β; IL-4; IL-10; IL-17; TNF-a; MIP-1a; I-TAC; IFN-g; IL-2; IL-8; IL-13; M-CSF) and Immunoglobulin A (IgA).
Results: Significant differences among the groups were observed regarding PD [2.2±0.39 and 2.4±0.32 (mean±SD); p<0.03] and BOP [10.3±9.68 and 19.7±13.9 (%±SD); p<0.05] for pre-term and on-term mothers, respectively. At both shallow and deep sites, pre-term mothers presented significantly higher levels of F. nuc ss nucleatum (p<0.001) and P. melaninogenica (p<0.0001) and lower T. forsythia (p<0.0001) and P. acnes (p<0.0001). Antibiotic use during pre-term labor was positively correlated with C. showae (p<0.001) and F. nuc ss nucleatum (p<0.05). The salivary concentrations (ng/mL) of IL-8 (661±443 and 1845±1559), IgA (7723±8309 and 14541±14787), IL-1β (595±581 and 1347±1064), and IL-2 (52±32 and 78±34) were significantly different (p<0.05) in pre-term group compared to the on-term, respectivelly. The salivary IL-2 and IL-8 concentrations were significantly and negatively correlated to F. nuc ss nucleatum (r=- 0.39, p<0.05).
Conclusions: Mothers with pre-term birth have significantly different microbiome and inflammatory profiles with a strong and confounding effect by their antibiotic use during pre-term labor.