The pathogenesis of ventilator-associated pneumonia

Of the four routes of infection pathogenic bacteria can take, the inhalation and aspiration ones are the most important. Inhalation pneumonia is usually due to manipulation of the ventilator tubing and aspiration of the infected condensate. Aspiration of the colonized oropharyngeal contents through the open vocal cords and eventually around the blown up endotracheal cuff allows bacteria to invade the trachea and main bronchi. Reflux of the bacteria and infection of the biofilm on the inner surface of the endotracheal tube is the source for recurrent seeding of pathogenic bacteria into the lungs, causing ventilator-associated pneumonia.