AveloMask, a novel breath aerosol collection kit for airborne Mycobacterium tuberculosis: a proof-of-principle assessment

Abstract

Tuberculosis (TB) remains the world’s deadliest infectious disease, with many active cases missed due to challenges in sputum collection. Exhaled breath aerosols (XBA), a major route of Mycobacterium tuberculosis (MTB) transmission, offer a promising non-invasive alternative. This study evaluated the diagnostic accuracy and feasibility of the AveloMask—a novel point-of-care breath aerosol collection kit—for detecting active pulmonary TB using quantitative PCR (qPCR). In a pilot diagnostic accuracy study, 61 symptomatic, adult outpatients in Cape Town, South Africa, wore the mask for 45 min, coughing deeply at the start and end. XBAs were collected on integrated fiber filters transferred into stabilizing buffer via a simple push step and biobanked. XBA’s were batch-analyzed by qPCR targeting the MTB-specific IS6110 sequence. Diagnostic accuracy was assessed against sputum Xpert MTB/RIF Ultra (SXRS) and a composite microbiological reference standard (MRS), including culture. Of the 58 evaluable participants, 59% (34/58) had confirmed TB. Compared with SXRS, mask qPCR showed 71.0% (95% confidence interval [CI]: 53.4%–83.9%) sensitivity and 92.3% (95% CI:75.9%–97.9%) specificity. Against MRS, sensitivity was 64.7% (95% CI: 47.9%–78.5%) and specificity 91.7% (95% CI: 74.2%–97.7%). Sensitivity increased with bacterial load, reaching 100% in sputum with high MTB concentrations. MTB IS6110 copy numbers in XBAs were low overall (175 copies [4–2,147]), likely due to insufficient DNA recovery or low aerosol bacilli. The mask sampling was well-tolerated by users. The AveloMask Kit shows promising diagnostic accuracy for TB and is feasible for point-of-care use. Further optimization and larger validation studies are warranted.