Nosocomial viral ventilator-associated pneumonia in the intensive care unit: a prospective cohort study

Objective: To determine the incidence, risk factors, and clinical relevance of viral ventilator-associated pneumonia (VAP) in an adult intensive care unit (ICU). Design: Prospective observational study. Setting: A 22-bed adult medical ICU in a university hospital. Patients: All consecutive adult patients ventilated more than 48 h in a 9-month period including regular seasonal viral infections. Interventions: A tracheobronchial aspirate upon enrollment and at the time of VAP suspicion. Measurements and results: All respiratory specimens were tested in culture, indirect immunofluorescence assay, and PCR or RT-PCR for virological assessment. Patients were followed until ICU discharge or death. One hundred thirty-nine patients were included. Upon enrollment, a respiratory virus was detected in the tracheobronchial aspirate in 25% of patients (35 of 139). The incidence of VAP, defined according to clinical daily evaluation, was 28% (39 of 139 patients). A bacteria was documented in 74% of cases, whereas no case of a causative viral infection was encountered among VAP patients; however, herpes simplex virus type-1 (HSV 1) infection was detected in respiratory specimens of 31% of VAP (12 of 39). Conclusions: We found a high incidence of HSV-1 infection in VAP patients; however, nosocomial viral VAP is likely to be rare in ICU, as assessed by the absence of respiratory virus-induced VAP identified in this prospective cohort study.