Utility of the BioFire® FilmArray® Pneumonia Panel Using Bronchial Washing Specimens: A Comparative Study with Conventional Culture

<b>Background:</b> Accurate identification of pneumonia pathogens is critical for guiding appropriate antibiotic therapy and minimizing unnecessary antimicrobial exposure. Bronchoalveolar lavage (BAL) is widely used for pathogen detection but introduces procedural risks. Bronchial washing (BW) is simpler and less invasive, yet evidence for its utility in multiplex PCR diagnostics is limited. <b>Methods:</b> This study includes an evaluation of the clinical utility of the BioFire^® FilmArray^® Pneumonia Panel (FA) using BW specimens via comparison with conventional culture. Between 2022 and 2024, 190 BW specimens were collected from 182 adult patients with suspected pneumonia at Eunpyeong St. Mary's Hospital, Seoul, Korea. Each specimen was tested simultaneously using FA and conventional culture. <b>Results:</b> The culture positivity rate was 41.6%, whereas FA showed a higher positivity rate of 51.1%. Of all specimens, 52.6% (100/190) were positive in at least one of two methods, and 11.0% (21/190) were FA-positive only. FA detected 72 additional bacterial targets, most commonly <i>H. influenzae</i>, <i>K. pneumoniae</i>, <i>S. aureus</i>, <i>S. agalactiae</i>, and <i>S. pneumoniae</i>. Semi-quantitative results demonstrated a statistically significant moderate correlation with culture (ρ = 0.48, <i>p</i> < 0.001). Eight bacterial targets achieved 100% PPA, and resistance genes were rapidly detected, although some discrepancies with phenotypic antimicrobial susceptibility testing were observed. Several FA-only detections may reflect oropharyngeal colonization rather than true infection. <b>Conclusions:</b> FA testing of BW specimens demonstrated high concordance with culture and provided rapid pathogen and resistance gene detection. BW-based FA testing may serve as a useful diagnostic alternative when BAL is not feasible, although careful interpretation is required to account for potential contamination.