[Epidemiology and antibiotic therapy in nosocomial pneumonia]

Nosocomial pneumonia occurs in 0.5 to 1.5% of all hospitalized patients and in 10 to 30% of those under artificial ventilation. The main causal agents are Staphylococcus aureus and resistant Gram-negative bacilli, particularly Pseudomonas aeruginosa. In case of early onset (before the fifth day), Haemophilus influenzae, Streptococcus pneumoniae and susceptible enterobacteria predominate. These infections are associated with overmortality, particularly in patients with P. aeruginosa pneumonia, severe respiratory failure, shock syndrome or given a poorly adapted antibiotic regimen. Management of patients with nosocomial pneumonia depends on the clinical presentation and prior bacteriology data often leading to empiric antibiotic prescription. Published guidelines, for example those recommended by the American Thoracic Society, can also be used to adapt the antibiotic therapy as a function of the severity of the clinical situation, the patient's comorbidities, and the date of onset. This type of strategy remains to be evaluated. It would be advisable to base therapeutic management on reliable microbiological data allowing selection of patients requiring antibiotics and treatment based on culture results. Currently a two-drug regimen is recommended for nosocomial pneumonia due to P. aeruginosa or particularly resistant strains.