Gram-negative bacterial pneumonia: aetiology and management.

PURPOSE OF REVIEW: Recent articles of clinical and investigational interest on Gram-negative pneumonia, particularly hospital-acquired and ventilator-associated pneumonia, are reviewed. RECENT
FINDINGS: The high rate of respiratory infections due to Gram-negative bacteria in late-onset ventilator-associated pneumonia has been repeatedly documented. The predominant pathogens are Pseudomonas aeruginosa and Acinetobacter baumannii. On the other hand, the frequency of Gram-negative bacteria in community-acquired pneumonia and in early-onset ventilator-associated pneumonia is increasing. Patients with risk factors for infection with resistant pathogens should initially receive a combination therapy that covers a broad spectrum, and, as soon as the pathogen and the susceptibilities are available, treatment should be simplified to a more targeted one (with the possible exception of P. aeruginosa pneumonia). Adequate dosing is of great importance and the use of pharmacodynamic/pharmacokinetic principles when prescribing antibiotics increases effectiveness. The optimal duration of therapy remains unknown; several studies have supported the use of shorter courses of treatment. Alternative treatment approaches (e.g. vaccines) are under investigation.
SUMMARY: The increasing frequency of resistant Gram-negative bacteria and the shortage of newer antibiotics in the pipeline with activity against Gram-negative bacteria is of concern. Early effective antimicrobial treatment is a key for the resolution of infection and improved survival.