Vidaur L, Planas K, Sierra R, Dimopoulos G, Ramirez A, Lisboa T, Rello J. (1)Critical Care Department. Joan XXIII University Hospital. Rovira i Virgili University & Pere Virgili Health Institute. Tarragona. Spain.; (2)Critical Care Department, Hospital Puerta del Mar, Cadiz. Spain.; (3)Critical Care Department, University Hospital Attikon, Athens. Greece.; (4) CIBER Enfermedades Respiratorias. Chest. 2008 Jan 15 PMID: 18198250

Background Clinical resolution of ventilator-associated pneumonia (VAP) determines the duration of treatment and mechanical ventilation. The aim of this study was to evaluate the influence of organisms and its susceptibility on outcomes.

METHODS: Prospective observational study in three teaching ICUs. Sixty episodes of VAP with appropriate therapy (Haemophilus influenzae=15, methicillin-sensitive Staphylococcus aureus (MSSA)=15, Pseudomonas aeruginosa=15 and methicillin-resistant Staphylococcus aureus (MRSA)=15), and 30 with initial inappropriate therapy, all due to Pseudomonas aeruginosa, were compared. Main outcome measures were clinical resolution variables and, in survivors, length of mechanical ventilation after VAP onset. Results Significant delay in resolution of hypoxemia was observed in VAP episodes due to MRSA and Pseudomonas aeruginosa with inappropriate antibiotic therapy (IAT) (median time to resolution 10 and 8 days, respectively) when compared with the remaining pathogens (median time to resolution 2 days). A multiple regression model, adjusted for disease severity confirmed delayed clinical resolution for MRSA and Pseudomonas aeruginosa with IAT. Similar associations were documented for defervescence. Among survivors, median duration of mechanical ventilation after VAP onset was significantly longer for MRSA (17 days) and Pseudomonas aeruginosa IAT (11 days) when compared with episodes due to Haemophilus influenzae or MSSA (6 days). Multiple regression analysis, adjusted for disease severity, confirmed that MRSA required significantly (R2 0.132, p<0.01) longer respiratory support than other organisms.

CONCLUSIONS: When treated promptly, resolution of VAP due to MSSA, Haemophilus influenzae and Pseudomonas aeruginosa was comparable. Resolution of MRSA VAP, regardless of the appropriateness of initial antibiotic therapy, was associated with longer respiratory support.