[Nosocomial pneumonia]

Abstract

Nosocomial pneumonia is a frequent complication, particularly during mechanical ventilation. Microbial patterns differ according to the time of onset: whereas early onset pneumonia (up to the fourth day of hospitalization) is mostly caused by Staphylococcus aureus, Streptococcus pneumoniae and Haemophilus influenzae, leading pathogens of late onset pneumonia (after the fourth day) additionally include gram-negative Enterobacteriaceae and potentially drug resistant microorganisms. These general patterns are modified in the presence of specific individual risk factors. The diagnostic work-up of pneumonia is aimed at the assessment of severity, the confirmation of the presence of pneumonia as well as the identification of the causal pathogens. The results of microbiological investigations must always be interpreted in the clinical context. Antimicrobial treatment must always be initiated empirically based on expected microbial patterns as outlined above. Nosocomial pneumonia in nonventilated and ventilated patients requires different empirical antimicrobial treatment approaches. All patients with antimicrobial treatment failures must be comprehensively reevaluated.