2026 Volume 4 Issue 1 Pages 46-52
Background: The usefulness of brush sampling has not been sufficiently investigated. This study evaluated the diagnostic value of brush sampling during bronchoscopy for detecting mycobacterial infections.
Materials and Methods: This retrospective study was conducted at Asahikawa Medical University Hospital between March 2014 and March 2024. Inclusion criteria comprised cases in which bronchial lavage or brush samples were tested for acid-fast bacilli (AFB) smear or culture. The primary analysis compared AFB smear detection rates in culture-positive cases between lavage alone and lavage with brushing, while the secondary analysis compared culture-positivity rates between both methods in patients with suspected mycobacterial infection.
Results: The number of AFB smear-positive cases detected by brush sampling was 8 out of 2,071 (0.38%), whereas positive AFB smears or cultures from bronchial lavage specimens was 65 out of 2,384 (2.72%). A total of 48 patients with a positive AFB culture result in either bronchial lavage or brush samples were included and divided into two groups: Group A (n = 24), patients with both brush and bronchial lavage samples; and group B (n = 24), patients with only bronchial lavage samples. Within group A, AFB positivity rates for bronchial lavage exceeded those for brush samples (47.1% vs. 29.1%, p = 0.083). The proportion of patients with positive AFB samples in group A did not differ from that in group B (45.8% vs. 45.8%, p = 1.00). Among 97 patients with suspected mycobacterial infection, culture positivity was similar between lavage plus brushing (54.5%, 24 out of 44) and lavage alone (45.3%, 24 out of 53; p = 0.418).
Conclusions: The addition of brush samples to bronchial lavage did not significantly improve the detection rate of AFB in smears or cultures.
