Aerosolization of by Tidal Breathing.

Interrupting tuberculosis (TB) transmission requires an improved understanding of how and when the causative organism, (), is aerosolized. Although cough is commonly assumed to be the dominant source of aerosols, recent evidence of cough-independent release implies the contribution of alternative mechanisms. To compare the aerosolization of bacilli and total particulate matter from patients with TB during three separate respiratory maneuvers: tidal breathing (TiBr), FVC, and cough. Bioaerosol sampling and enumeration by live-cell, fluorescence microscopy were combined with real-time measurement of CO concentration and total particle counts from 38 patients with GeneXpert-positive TB before treatment initiation. For all maneuvers, the proportions of particles detected across five size categories were similar, with most particles falling between 0.5-5 μm. Although total particle counts were 4.8-fold greater in cough samples than either TiBr or FVC, all three maneuvers returned similar rates of positivity for . No correlation was observed between total particle production and count. Instead, for total counts, the variability between individuals was greater than the variability between sampling maneuvers. Finally, when modelled using 24-hour breath and cough frequencies, our data indicate that TiBr might contribute more than 90% of the daily aerosolized among symptomatic patients with TB. Assuming the number of viable organisms released offers a reliable proxy of patient infectiousness, our observations imply that TiBr and interindividual variability in release might be significant contributors to TB transmission among active cases.