Does cytomegalovirus play a role in community-acquired pneumonia?

Cytomegalovirus (CMV) is recognized as an important pathogen in the immuno-suppressed patient. Sporadic case reports of cytomegalovirus community-acquired pneumonia have appeared. We studied 443 patients with community-acquired pneumonia requiring hospitalization to define the role of cytomegalovirus in this illness. Four patients (0.9%) had good evidence that cytomegalovirus caused their pneumonia: 2 had the virus isolated from pulmonary tissue and 2 had cytomegalovirus inclusion bodies visualized in this tissue. An additional 14 patients had serologic evidence (a fourfold rise in the complement fixation tests) of cytomegalovirus infection. Analysis of these 18 patients suggest, that cytomegalovirus plays a role in community-acquired pneumonia. Six (33%) of the patients were immunosuppressed. Six others had concomitant infections: Chlamydia trachomatis (3); Epstein-Barr virus and M. pneumoniae (1); and bacteremia with Group B streptococcus and Bacteroides fragilis plus Eubacterium lentum (1 each). Seven patients (39%) required assisted ventilation, four of whom developed secondary bacterial pneumonia. Five (28%) died. Only two patients had a clinical and radiographic picture suggestive of a viral illness as a cause of the pneumonia. Three patients had atypical lymphocytes in their peripheral blood film. We found that the prevalence of complement fixing antibody to cytomegalovirus increased with age. Such antibody was lacking among those in the 16-20 year group while it peaked at 65% for males and at 78% for females ages 91-100 years. Despite the fact that 42.2% of the adults lacked antibody to cytomegalovirus, community-acquired pneumonia due to this virus is uncommon and does not justify routine serological testing for such infection among patients with community-acquired pneumonia.