the tracheal aspirate; radiographic cavitation; histo- pathologic evidence of pneumonia; or two of the fol- lowing including fever (>38 C), leukocytosis (white blood cell >12,000/mm3), and purulent tracheal aspirate (>25 white blood cells/high power field). Associated organisms were designated as those organisms recov- ered from tracheal aspirates from the patients with VAP. Crude mortality associated with VAP is defined as pa- tient mortality occuring within 2 weeks after the devel- opment of VAP and is not attributable to other etiolo- gies. Data analysis was performed using SPSS Ver-
sion 10.0 (SPSS, Chicago, IL). Categorical variables were compared using Chi Square Test or Fisher Exact Test, as appropriate. Continuous variables were compared using the Wilcoxon rank sum test. All P values were two tailed; p