Importance of viral and bacterial infections in chronic obstructive pulmonary disease exacerbations

Few studies have evaluated the contribution of both viruses and bacteria in acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

This study estimated the burden of both types of pathogens among adults seeking care for an AECOPD during two consecutive winter seasons.

Patients 50 years or older who consulted within 10 days of AECOPD onset were eligible. Clinical data were collected on a standardized questionnaire, and nasopharyngeal aspirates (NPA), paired sera, and non-induced sputum were collected. Polymerase chain reaction (PRC) assays were used to identify viral, atypical and bacterial pathogens in NPA specimen.

Overall, 108 patients with AECOPD were included, 88% of patients were admitted and 2 patients (2%) received intensive care. A third of patients (31%) had evidence of a viral infection, 9% with influenza A, 7% RSV and 7% with PIV-3. One patient was positive for Mycoplasma pneumoniae. Bacterial pathogens were identified in 49% of patients with available sputum, most frequently Staphylococcus aureus, Pseudomonas aeruginosa, and Haemophilus influenzae. Among virus-infected patients, 14 (58%) also had bacteria in their sputum, but co-infected patients did not present with different symptoms than patients with single infections.

These results suggest that influenza and RSV are frequent contributors of AECOPD, and that coinfection with bacteria does not appear to be more severe among virus-infected patients. Clinicians should be aware that AECOPD may be frequently triggered by viruses, and may consider antivirals and proper infection control measures in appropriate epidemiological setting.