Risk factors for HAP promoting colonization with pathogenic organisms and their aspiration include the use of healthcare devices or the environment (air, water, equipment, and fomites) and can occur with transfer of microorganisms between staff and patients (3,7-9,15-20). Aspiration of oropharyngeal pathogens or leakage of bacteria around the endotracheal tube cuff is the primary route of bacterial entry into the trachea (21-24). The stomach and sinuses have been suggested as potential reservoirs for certain bacteria colonizing the oropharynx and trachea, but their importance remains controversial (25-30). Some investigators postulate that colonization of the endotracheal tube with bacteria encased in biofilm may result in embolization into the alveoli during suctioning or bronchoscopy (31,32). Inhalation of pathogens from contaminated aerosols and direct inoculation are less common (33,34).