Bouzid D et al., Agreement of respiratory viruses’ detection between nasopharyngeal swab and bronchoalveolar lavage in adults admitted for pneumonia: a retrospective study, Clin Microbiol Infect, 2023

Bouzid D, Hingrat QL, Salipante F, Ferré VM, Chevallier T, Tubiana S, Lucet JC, Choquet C, Yazdanpanah Y, Timsit JF, Descamps D, Houhou N, Visseaux B, Loubet P

Clin Microbiol Infect 2023 doi: 10.1016/j.cmi.2022.12.024


Objectives: The COVID-19 pandemic has highlighted the high diagnostic accuracy of the nasopharyngeal swab (including in intensive care unit (ICU) patients). This study aimed to compare nasopharyngeal swab and bronchoalveolar lavage (BAL) results for non-SARS-CoV-2 viruses in patients with suspected pneumonia.

Methods: A retrospective analysis was performed in one French academic hospital on consecutive adults from 2012 to 2018 and tested nasopharyngeal swab and BAL within 24 hours by using multiplex PCR. The agreement in pathogen detection between nasopharyngeal swab and BAL was evaluated.

Results: Patients were primarily men (n = 178/276, 64.5%), with a median age of 60 years (IQR: 51-68 years). Of the 276 patients, 169 (61%) were admitted to the ICU for acute respiratory distress. We detected at least one respiratory virus in 34.4% of the nasopharyngeal swabs (n = 95/276) and 29.0% of BAL (n = 80/276). Two or more viruses were detected in 2.5% of the nasopharyngeal swabs (n = 7/276) and 2.2% of BAL (n = 6/276). Rhinovirus/enteroviruses were the most frequently detected viral group in 10.2% (n = 29/285) of the nasopharyngeal swabs and 9.5% (n = 27/285) of BAL, followed by influenza A, detected in 5.6% (n = 16/285) of the nasopharyngeal swabs and 4.9% (n = 14/285) of BAL. Overall agreement was 83.7% (n = 231/276 (95% CI [78.7%, 87.7%])) (i.e. same pathogen or pathogen combination was identified in the nasopharyngeal swab and BAL for 231 patients). Rhinovirus/enterovirus (n = 29/231) and respiratory syncytial virus (n = 13/231) had the lowest agreement of 62.1% (n = 18/29 (95% CI [42.4%-78.7%])) and 61.5% (n = 8/13 (95% CI [32.3%-84.9%])), respectively).

Conclusions: There was a good agreement between nasopharyngeal swabs and BAL in detecting respiratory viruses among adult patients with suspected pneumonia. However, these data still encourage BAL in the case of a negative nasopharyngeal swab.