Virological diagnosis in community-acquired pneumonia in immunocompromised patients

¹ Dept of Microbiology, Hospital Clínic i Provincial de Barcelona, Spain
² Dept of Infectious Diseases, Hospital Clínic i Provincial de Barcelona, Spain
³ Dept of Pneumology, Institute of Pneumology and Thoracic Surgery, Hospital Clínic i Provincial de Barcelona, Institut d'Investigacions Biomèdiques Agustí Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Spain

	Abstract

Community-acquired pneumonia (CAP) is a serious lower respiratory tract infection associated with significant morbidity and mortality in immunocompromised patients.

The present study evaluated the clinical spectrum of community-acquired pneumonia in immunocompromised hosts, the role of respiratory viruses, as well as the yield of viral diagnostic methods.

Conventional microbiological tests were routinely performed in immunocompromised patients with CAP. Nasopharyngeal swabs were processed for respiratory viruses by indirect immunofluorescence assay, cell culture and PCR. We defined 4 groups according to aetiology of CAP: group 1 (non viral), group 2 (mixed, non-viral and viral), group 3 (only viral) and group 4 (unknown aetiology).

Over a one year period, 92 patients were included. An aetiological diagnosis was achieved in 61 (66%) patients: 38 (41%), group 1; 12 (13%), group 2; and 11 (13%), group 3. The most frequent pathogen detected was Streptococcus pneumoniae (n=29, 48%) followed by rhinovirus (n=11, 18%). PCR identified 95% of respiratory viruses. Clinical characteristics could not reliably distinguish among the different aetiologic groups.

Respiratory viruses represent a substantial part of the aetiologies of CAP in immunocompromised patients and its routine assessment through PCR in nasopharyngeal swabs should be considered in the clinical care of these patients.