Association of Number of Oral bacteria with Ventilator-Associated Pneumonia and Delirium in Patients in the Intensive Care Unit

Objectives: Ventilator-associated pneumonia (VAP) and delirium are major complications among patients in the intensive care unit (ICU). The impact of oral bacterial count on these conditions is not well understood. This study aimed to explore the association between oral bacterial load and the incidence of VAP and delirium in ICU patients. Methods: In this single-center longitudinal study, 130 patients admitted to the ICU from September 2022 to May 2023 were included. Oral bacteria counts on the tongue were quantified, and assessments of oral health using the Oral Health Assessment Tool (OHAT) and oral moisture levels were also conducted. We examined the associations between oral bacterial count, OHAT scores, and oral moisture with the incidence of VAP and delirium. Results: The incidence rates of VAP and delirium were 31.4% and 35.4%, respectively. Patients with a high oral bacterial load (≥5.0 × 10⁷ CFU/mL) at ICU admission had a higher likelihood of developing VAP (odds ratio [OR] 7.43, 95% confidence interval [CI] 1.68-32.87) and delirium (OR 3.30, 95% CI 1.04-10.44) compared with those with lower bacterial counts (<1.0 × 10⁷ CFU/mL). No significant associations were found between OHAT scores and oral moisture and the occurrence of VAP or delirium. Conclusion: A higher oral bacterial count at ICU admission was associated with increased incidences of VAP and delirium.