Oral Microbiota Change in Intubated Patients under Mechanical Ventilation

Abstract

One of the complications that may develop in intubated patients under mechanical ventilator is ventilator-associated pneumonia (VAP). In most cases, VAP appears to result from aspiration of the oropharyngeal microflora or colonizing pathogens. For efficient prevention and management, understanding oral microbiome dynamics during mechanical ventilator is required. In this study, we analyzed longitudinal oral microbiome in intubated patients under mechanical ventilation support. Intubated patients and healthy subjects were recruited for this study. Buccal samples were collected for microbiome study. For longitudinal comparison, intubated samples were grouped as initial 2 days, first week, second week, third week, and over 3 week group. 16S ribosomal RNA next generation sequencing was applied for microbiome analysis. Alpha diversity and beta diversity was applied to characterize the oral microbiome. Linear discriminant analysis effect size (LefSe) was applied to determine difference in the composition among tested group. In intubated patients, the richness and evenness of the microbiota was significantly reduced compared to the healthy control. The most abundant species in intubated patients were Corynebacterium, Acinetobacter, Streptococcus, Staphylococcus, and Enterococcus, which represented more than 70% of the total sequences at the genus level. The most abundant species were Acinetobacter baumannii, Proteus mirabilis, Enterococcus faecalis Pseudomonas aeruginosa, and Gardnerella vaginalis were among the significant taxa within intubated patients. Pathogenic bacteria including Acinetobacter, Enterococcus, Klebsiella, Pseudomonas, and Staphylococcus were also frequently observed during the observation period. In intubated patients, the composition of oral microbiome was heavily distorted compared to healthy subjects and high abundance of pathogenic bacteria was observed. A better understanding of the longitudinal microbiome change in oral cavity of intubated patients should provide better understanding for effective prophylactic and therapeutic interventions for VAP.