<prompt> Definition of VAP is:Defined as pneumonia occurring 48 hours or more after admissionDefined as pneumonia occurring 48 hours or more after intubationDefined as pneumonia occurring within 48 hours of hospital admissionDefined as pneumonia occurring within 48 hours of intubation  <response>: Ventilator-associated pneumonia VAP is pneumonia that develops 48 hours or longer after mechanical ventilation is given by means of an endotracheal tube or tracheostomy. Ventilator-associated pneumonia VAP results from the invasion of the lower respiratory tract and lung parenchyma by microorganisms. VAP is estimated to occur in 9-27 of all mechanically ventilated patients, with the highest risk being early in the course of hospitalization 