Oral care for intubated patients in the intensive care unit: examination of bacterial count and microbiota

Background: Ventilator-associated pneumonia (VAP) after tracheal intubation is a major infectious complication in patients in the intensive care unit (ICU), with an incidence of 8–28%. Oral care in the ICU is essential; however, the presence of an intubation tube and restricted mouth opening cause complications. A healthy commensal microflora in the oral cavity resists colonization by respiratory pathogens, and poor oral hygiene may increase the risk for VAP. In this study, we examined the effectiveness of oral care on oral bacterial counts and microbial diversity in patients admitted to the ICU. Methods: Fifteen ICU patients were included in this study. Oral microbiome samples were collected by swabbing the surface of the tongue. Oral bacterial counts were measured at four time points: before and after oral care, both pre- and post-extubation. Additionally, microbiome analysis was conducted twice: once before oral care pre-extubation, and once before oral care post-extubation. Oral bacterial counts were assessed using a bacterial counter, and microbiome analysis was performed through 16S rRNA gene amplicon sequencing. Results: Oral bacterial counts significantly decreased after oral care at both pre- and post-extubation time points. Microbiome analysis revealed significant differences in alpha diversity pre- and post-extubation samples. Samples post extubation were less diverse. Conclusions: This study demonstrates that oral care effectively reduces bacterial counts in ICU patients, both pre- and post-extubation. Microbiome analysis revealed shifts in microbial diversity, suggesting that the oral microbiota was disrupted during intubation. Given the risk of VAP, oral care may play an important role to prevent VAP in ICU settings.