Clinical significance of a positive serology for mimivirus in patients presenting a suspicion of ventilator-associated pneumonia

Objective: A seroconversion to mimivirus has been observed in patients with community-acquired or nosocomial pneumonia. The aim of this study was to determine whether a positive serology for mimivirus was associated with increased morbidity and mortality in patients with a suspicion of ventilator-associated pneumonia (VAP). Design: Prospective matched-cohort study. Setting: A 12-bed medical intensive care unit (ICU) in a teaching hospital. Patients: Patients ventilated for at least 2 days presenting with a suspicion of VAP Patients with a positive serology for mimivirus were matched to seronegative patients. Interventions: None. Measurements and Main Results: Matching criteria were: 1) the same main diagnosis on ICU admission, 2) the same age (+/- 10 yrs), 3) the same Simplified Acute Physiology 11 score (+/- 10 points), 4) the same McCabe and Jackson comorbidity score, 5) admission within 1 year, and 6) diagnosis of at least one bacterial VAP during the ICU stay or not. A total of 55 pairs were submitted for analysis. The effectiveness of matching was 94.8%. Patients with a positive serology for mimivirus had longer duration of mechanical ventilation and ICU stay with median excesses of 7 days and 10 days, respectively. There was no difference in ICU mortality. The duration of mechanical ventilation before bronchoalveolar lavage (adjusted odds ratios [OR]1.08, p = 0.02), viral identification other than mimivirus during ICU stay (adjusted OR 0.32, p = 0.05), and enteral nutrition (adjusted OR 0.13, p = 0.01) were associated with positive serology for mimivirus. Conclusion: A positive serology for mimivirus is associated with a poorer outcome in mechanically ventilated ICU patients. (Crit Care Med 2009; 37:111-118)