Oral colonization patterns according to ventilatory support modality in critically ill patients

Aim To evaluate oral colonization patterns according to ventilatory support modality in critically ill patients, with particular emphasis on colonization involving hospital-associated Gram-negative bacilli because of their relevance to healthcare-associated respiratory infections. Methods and results A cross-sectional study included 120 adults admitted to two intensive care units in Brazil. Participants were equally allocated into three groups according to ventilatory support modality: no invasive ventilation, endotracheal tube, and tracheostomy. Oral samples collected from the dorsal surface of the tongue were analyzed using conventional culture methods. Oral colonization patterns differed significantly according to ventilatory support modality (p < 0.001). Colonization involving hospital-associated Gram-negative bacilli (isolated or mixed) increased progressively from 45.0% among patients without invasive ventilation to 62.5% among those with an endotracheal tube and 92.5% among tracheostomized patients. Conversely, conventional oral microbiota decreased from 40.0% to 25.0% and 5.0%, respectively. Salivary flow patterns also differed significantly among groups (p = 0.047). Discussion Increasing invasiveness of ventilatory support was associated with progressive oral colonization involving hospital-associated Gram-negative bacilli and a concomitant reduction in conventional oral microbiota. Although causality cannot be inferred because of the cross-sectional design, the findings support the concept that the oral cavity may serve as a reservoir of respiratory pathogens in critically ill patients. Significance and impact Characterizing oral colonization patterns according to ventilatory support modality may support infection prevention and control programmes by informing risk stratification and evidence-based oral care strategies in intensive care units.