[Nosocomial pneumonia in intensive care units].

Nosocomial pneumonia is associated with substantial morbidity and mortality. Patients treated with mechanical ventilation have the highest risk for developing this intensive care unit acquired infection. Gram-negative bacilli are the predominant organisms responsible for pneumonia in this setting. However, Staphylococcus aureus has recently emerged as a significant isolate. Nosocomial pneumonia is difficult to diagnose clinically in ventilated patients because fever, lung infiltrate on chest X-ray, leukocytosis are frequent in severely ill patients under mechanical ventilation whatever lung infection is present or not and because lower respiratory tract of such patients is colonized by potentially pathogenic bacteria independently of the presence of true lung infection; thus, different diagnostic strategies are proposed. Our personal bias is that using bronchoscopic techniques to obtain bronchoalveolar lavage and protected-brush specimens permits us to devise a therapeutic strategy that is superior to one based only on clinical evaluation. Measures for prevention of nosocomial infection are essential to decrease the incidence of nosocomial pneumonia and the emergence of multiresistant pathogens.