Impact of Previous Antimicrobial Therapy on the Etiology and Outcome of Ventilator-associated Pneumonia

To define the influence of prior antibiotic use on the etiology and mortality of ventilator-associated pneumonia (VAP). A university hospital medical-surgical ICU. Prospective clinical study. Over a 35-month period, we prospectively studied 129 consecutive episodes of VAP. Etiologic diagnosis was established using a protected specimen brush and quantitative culture techniques. We examined prognostic factors by univariate and multivariate analyses using a statistical software package (SPSS). The rate of VAP caused by Gram-positive cocci or Haemophilus influenzae was statistically lower (p