Subglottic microbiota in periodontitis patients undergoing short-term endotracheal intubation: a pilot study

Objectives: It remains uncertain whether oral bacteria, especially in periodontitis, enter the lower respiratory tract via tracheal intubation during anesthesia. This pilot study aimed to characterize subglottic microbiota profiles in patients with or without periodontitis before and after 1-hour endotracheal intubation. Methods: Female patients undergoing gynecological surgery with endotracheal intubation were divided into periodontitis (n = 24) and periodontally healthy control (n = 17) groups. Unstimulated saliva was collected pre-anesthesia. Subglottic lavage samples were obtained immediately after anesthesia induction (pre-intubation) and 1-hour post-intubation. Microbial composition was analyzed via 16S rRNA sequencing. Results: Statistically significant differences were observed primarily in salivary microbiota: compared to the control group, the periodontitis group had significantly higher abundances of periodontopathogens in saliva, including Porphyromonas gingivalis, Treponema denticola, and Prevotella intermedia (all P < 0.05). Additionally, the relative abundance of the phylum Spirochaetota was five-fold higher in the saliva of periodontitis patients (0.73%) than in controls (0.14%, P < 0.05). In contrast, subglottic microbiota showed distinct compositional patterns from saliva across all groups, with Proteobacteria being the dominant phylum (65.44%–78.58% of total taxa). Post-intubation, the periodontitis group exhibited a non-significant upward trend in subglottic levels of periodontopathogens (e.g., P. gingivalis, T. denticola), whereas the control group showed a non-significant downward trend in these taxa(P > 0.05). Conclusion: This pilot study demonstrates that subglottic microbial communities differ from salivary microbiota and identifies an exploratory, non-significant trend suggestive of a potential association between periodontitis and altered subglottic periodontopathogen levels following short-duration intubation. These findings suggest a potential value in pre-anesthetic oral health assessment, though further studies with larger cohorts and clinical outcome data are required to confirm clinical relevance.