Procalcitonin (PCT), a relatively novel marker of infectious processes, has been shown to be associated with the severity of inflammation and prognosis during sepsis and septic shock [14] [15] [16] . In two large studies in the emergency department, low PCT-values were associated with a low risk of death in patients with CAP [17, 18] . Luyt and colleagues reported that PCT levels decreased during the clinical course of VAP but were significantly higher from Day 1 to Day 7 in patients with unfavorable outcomes [19] . The significance of PCT is emphasized by the observation that the course of PCT levels may safely guide antimicrobial therapy in patients with community acquired lower respiratory tract infections [20, 21] and ICU patients with suspected bacterial infections [22] . However, data about the significance of PCT in patients with hospital and ventilator acquired pneumonia requiring intensive care therapy are still limited.