Fig. 1: Mechanisms of ventilator-acquired pneumonia.

1 External factors associated with ICU therapies include mechanical ventilation, sedation and paralysis agents and semi-recumbent positioning; 2 Endotracheal tube prevents glottis closure and provides direct communication to the lungs, allowing microaspiration of secretions from the nasal sinuses and oropharynx. The endotracheal cuff is at risk of deflation, movement and small folds, allowing pooled secretions to leak. A bacterial biofilm can form around the endotracheal tube, which can then become dislodged by movement or suctioning; 3 In response to invading pathogens, alveolar macrophages and neutrophils’ immune and inflammatory response lead to inflamed, oedematous and infected alveoli. Abbreviations: ICU = intensive care unit; AM = alveolar macrophages. Figure 1 was created with BioRender.com released under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International license (https://creativecommons.org/licences/by-nc-nd/4.0/deed.en).