The role of viruses in nosocomial pneumonia.
OBJECTIVE
The frequency and impact of viruses among intensive care unit (ICU) nonimmunocompromised patients remains controversial. This review analyzes their place as causal pathogens in ventilator-associated pneumonia, as well as their effects on ICU patients' outcomes.


RESULTS
Herpesviruses, namely herpes simplex virus (HSV) and cytomegalovirus (CMV), are the most frequent viruses detected among nonimmunosuppressed ICU patients, as confirmed by recent prospective studies. Patients infected with these viruses show increased morbidity and, especially for CMV, mortality. An increase of bacterial or fungal superinfections was observed in ICU patients with CMV reactivation. A therapeutic trial of acyclovir (HSV antiviral) in ICU patients was negative. Concerning CMV, pathogenicity was suggested by histologic assessment in ICU patients, and recent murine models with a positive effect of prophylaxis with ganciclovir that prevented postseptic CMV reactivation and secondary lung damage.


CONCLUSIONS
Using efficient and rapid virologic diagnostic tests (antigenemia or PCR), the identification of viruses in ICU patients is frequent. Their role in the occurrence of ventilator-acquired pneumonia and their impact on patient outcome depend on the virus. There is sufficient evidence suggesting CMV pathogenicity to conduct an interventional randomized trial using anti-CMV drugs.
Réanimation Médicale, Assistance Publique - Hôpitaux de Marseille, URMITE CNRS-UMR 6236, Université de la Méditerranée, Marseille, France.
Laurent
L
Chiche
Jean-Marie
JM
Forel
Laurent
L
Papazian
D003428:Cross Infection / Q000175:diagnosis / Q000453:epidemiology / Q000635:transmission / Q000821:virology*; D003586:Cytomegalovirus Infections / Q000175:diagnosis / Q000453:epidemiology / Q000635:transmission / Q000821:virology; D006561:Herpes Simplex / Q000175:diagnosis / Q000453:epidemiology / Q000635:transmission / Q000821:virology; D017052:Hospital Mortality; D006801:Humans; D007121:Immunocompetence; D007362:Intensive Care Units; D053717:Pneumonia, Ventilator-Associated / Q000175:diagnosis / Q000453:epidemiology / Q000821:virology*; D011024:Pneumonia, Viral / Q000175:diagnosis / Q000453:epidemiology / Q000635:transmission / Q000821:virology*