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Full list of author information is available at the end of the articleBackground Nosocomial pneumonia, which is usually defined as hospital-acquired pneumonia (HAP), is the second most frequent nosocomial infection but the first in terms of morbidity, mortality and cost. It occurs in 8-20 % of intensive care unit (ICU) patients, with an increased fre-quency and mortality if the patients are mechanically ventilated [1-4]. Over the past decade, several risk fac-tors associated with mortality have been detected in HAP and ventilator-associated pneumonia (VAP). One of the most consistent and evident prognostic factor throughout the literature is the accuracy of initial anti-biotic treatment (AB). By contrast, early aggressive therapy with adequate broad-spectrum regimens that optimize therapy against the likely pathogens is asso-ciated with lower mortality rates and shorter hospital * Correspondence