Epidemiology of respiratory viruses in bronchoalveolar lavage samples in a tertiary hospital

Background: The prevalence of respiratory viruses in adults is largely underexplored, as most studies focus on children. Additionally, in severely ill or immunocompromised adults, where respiratory infections are mostly attributed to bacteria and fungi; respiratory viruses can lead to severe complications.

Objectives: To evaluate the epidemiology of respiratory viruses in bronchoalveolar lavage fluid (BAL) specimens from patients with lower respiratory tract disease. The study population consisted of different groups including immunocompetent patients (control patients), solid organ transplant recipients, patients with haematological malignancies and other immunocompromised adults.

Study design: A total of 134 BAL fluid specimens collected during 2009-2011 were retrospectively assessed with the new commercial multiplex real-time PCR FTD Respiratory 21 Plus(®), targeting 18 different viruses and 2 atypical bacterial pathogens.

Results: Viral or atypical bacterial pathogens were detected in 29.1% of BAL fluid specimens. Coronaviruses were most prevalent (13.4%), followed by rhinoviruses (5.2%), RSV (4.5%) and bocaviruses (3.7%). Comparing the total number of viruses detected, a statistically significant difference was observed between the control group and patients with haematological malignancies (27.5% vs. 57.1%, p<0.05).

Conclusion: In conclusion, our study highlights the high prevalence of respiratory viruses in BAL fluid specimens from adult patients with lower respiratory tract disease. The methods to be used should be sensitive and cover a wide range of potential pathogens. The specific patient population can also influence the detection rates of respiratory viruses.