Pathogenesis of post-traumatic ventilator-associated pneumonia

Abstract

Objective To study the role of changes of oropharyngeal microflora in pathogenesis of post-traumatic ventilator-associated pneumonia (VAP). Methods Forty-five patients with post-traumatic VAP treated with intubation and mechanical ventilation were involved in the study.Microbiologic cultures and drug-sensitivity test of oropharyngeal secretions,subglottic secretions,sputum from deep airway and gastric fluid samples were performed at days 1,3,7 and 14 after mechanical ventilation.The stool samples were collected to detect the coccus and bacillus ratio and the fungus.The concordance rate of microflora among subglottic secretions,sputum,gastric fluid and oropharyngeal secretions were compared. Results The main pathogens for VAP patients were gram-negative bacilli.The study showed an increase in aspects of the positive rate of etiology cultures of subglottic secretions,sputum and gastric fluid samples,the concordance rate of microflora among subglottic secretions,sputum,gastric fluid and oropharyngeal secretions and the number of ESBL + and multi-resistant bacteria,along with the prolonged mechanical ventilation. Conclusions The changes of oropharyngeal microflora are closely associated with the development of VAP.The enterobacteria in the gastric cavity always reversely colonize in the oropharynx and the retrograde stomach-pharynx-lower respiratory tract infection is a major infection route of VAP. Key words: Pneumonia, ventilator-associated; Oropharynx; Bacterial infections