A patient with severe neurological devastation after head trauma has a prolonged course in the intensive care unit. He has been mechanically ventilated for his entire hospital stay. Which of the following clinical findings is diagnostic of a ventilator-associated pneumonia?

While findings such as fever, leukocytosis, purulent secretions, or a focal infiltrate on chest x-ray are suspicious for ventilator-associated pneumonia (VAP), quantitative cultures are diagnostic. Samples may be obtained using bronchoscopy with bronchoalveolar lavage (BAL). Greater than or equal to 10,000 colony-forming U/mL of a single organism is diagnostic for VAP. Empiric antibiotics may be initiated after cultures are obtained based on clinical suspicion, but antibiotic coverage should be narrowed or stopped once an organism is identified to minimize development of resistant organisms