Invasive mechanical ventilation is a risk factor for the development of pneumonia,1,2 being the ventilator-associated pneumonia (VAP) a public health problem. VAP is a hospital-acquired pneumonia which occurs in patients who were subjected to invasive mechanical ventilation, whether through tracheostomy or endotracheal intubation, at least 48 hours before the onset of infection and that were ventilated at the onset of the pneumonia.3 This disease is also classified according to the time elapsed from the beginning of the mechanical ventilation (MV) to the onset of pneumonia; it is considered as early-onset if it occurs within 4 days of the start of MV, and late-onset if it occurs after 5 or more days of MV onset.4,5 However, not all the studies consider early- and late-onset VAP within the same time range frame (Table 1).