Breath aerosol PCR for detection of lower respiratory tract infections: evaluation of a non-invasive face mask collector in pneumonia patients.

Etiological diagnosis of lower respiratory tract infections (LRTIs) relies on sputum or bronchoalveolar lavage (BAL), which may be difficult to obtain or invasive. Exhaled breath aerosol (XBA) sampling offers a noninvasive alternative for pathogen detection. We evaluated the performance of the AveloMask, a face mask-based device designed to capture XBAs for molecular testing. In this prospective paired-sample study, hospitalized adults with pneumonia at three hospitals in Switzerland and Georgia provided an XBA sample using the AveloMask and a lower respiratory tract (LRT) specimen (sputum or BAL). XBA samples were analyzed by multiplex PCR using the Roche LightMix® panel, and LRT samples were tested using the BioFire® FilmArray® Pneumonia Panel. Concordance between XBA and LRT samples was assessed using positive percent agreement (PPA), negative percent agreement (NPA), and overall percent agreement (OPA). A total of 93 participants were enrolled, and 63 participants provided paired samples. AveloMask sampling identified the dominant pathogen (lowest Ct value in the LRT sample) in 40/47 LRT-positive cases (85.1%). Across all targets, PPA was 61% (95% CI, 50%-72%), NPA was 99.8% (95% CI, 99%-100%), and OPA was 95% (95% CI, 92%-96%). PPA was higher for bacteria than for viruses, and lower PPA was largely driven by reduced detection of low-abundance or co-infecting pathogens. In an exploratory subset analysis, AveloMask results overlapped with standard-of-care testing and may have informed antimicrobial decision-making. Breath aerosol sampling using the AveloMask enabled noninvasive molecular detection of LRT pathogens in pneumonia cases and may complement conventional standard-of-care testing, particularly when sputum is unavailable.IMPORTANCEPneumonia diagnosis often relies on sputum samples, which many patients cannot provide, or bronchoscopy, which is invasive. This study evaluated a user-friendly face mask that captures exhaled aerosols released during normal breathing and coughing for laboratory testing. In hospitalized patients with pneumonia, the mask identified the most abundant pathogen in most cases and was well tolerated in routine clinical care. These findings show that breath aerosol sampling could provide a practical, noninvasive complement to existing diagnostic methods, especially when sputum is unavailable or difficult to obtain. By making lower respiratory tract (LRT) sampling easier and more accessible, this approach could support faster, more targeted treatment decisions, reduce unnecessary antibiotic use, and expand opportunities for molecular diagnosis in hospitals and other healthcare settings.This study is registered with ClinicalTrials.gov as NCT06668883.