Cough-independent production of viable Mycobacterium tuberculosis in bioaerosol

Patterson, Benjamin; Bryden, Wayne A.; Call, Charles J.; McKerry, Andrea; Leonard, Bryan; Seldon, Ronnett; Gqada, Melitta; Dinkele, Ryan; Gessner, Sophia; Warner, Digby F.; Wood, Robin

doi:10.1016/j.tube.2020.102038

Cited by 20 publications

(27 citation statements)

References 26 publications

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“…Using this platform, we detected Mtb bacilli in the absence of (induced) Cough. More recently, we compared deep exhalations to Cough and found no difference in Mtb aerosolization (10). However, these observations were not conclusive given that we did not directly investigate the propensity for respiratory aerosol production in each manoeuvre.…”

Section: Introductionmentioning

confidence: 84%

“…According to this model, particles are produced during inspiration by alveolar reopening and released through expiration (21). Factors impacting particle release are therefore the rate of inspiration and the depth of expiration (21), with a recent study comparing deep exhalation and Cough finding no significant difference in the number of Mtb aerosolized between the two manoeuvres (10). For these reasons, we hypothesized that TiBr contributes to the aerosolization of Mtb.…”

Section: Discussionmentioning

confidence: 99%

“…Bioaerosols from three respiratory manoeuvres, Forced Vital Capacity (FVC), Tidal Breathing (TiBr), and Cough, were captured in liquid cyclone collectors utilising a direct sampling strategy (Figure 1A) (10). A unidirectional airflow forced exhaled air via a CO2 monitor and a high-flow cyclone collector at a maximum flow rate of 300 L/minute, trapping particulate matter in the collection medium (sterilised phosphate-buffered saline, PBS).…”

Section: Sample Collectionmentioning

confidence: 99%

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Aerosolization of Mycobacterium tuberculosis by tidal breathing

Dinkele

Gessner

McKerry

et al. 2021

Preprint

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Rationale: Interrupting tuberculosis (TB) transmission requires an improved understanding of how - and when - the causative organism, Mycobacterium tuberculosis (Mtb), is aerosolized. Although Cough is commonly assumed to be the dominant source of Mtb aerosols, recent evidence of Cough-independent Mtb release implies the contribution of alternative mechanisms. Objective: To compare the aerosolization of Mtb and particulate matter from GeneXpert-positive patients during three separate respiratory manoeuvres: Tidal Breathing (TiBr), Forced Vital Capacity (FVC), and Cough. Methodology: Bioaerosol sampling and Mtb detection were combined with real-time assessments of CO2 production and particle counts from 39 confirmed TB patients. Measurements and Main Results: TiBr and FVC produced comparable numbers of particles, with Cough producing >4-fold more. For all manoeuvres, the proportions of particles detected across size categories from 0.5 - 5 µm were similar, with minor differences observed only in particles between 1.5 - 2 µm (p = 0.014) and >5 µm (p = 0.020). Viable Mtb bacilli were detected in 66%, 70%, and 65% of TiBr, FVC, and Cough samples, respectively. Notably, while Cough produced 3-fold more Mtb than TiBr, the relative infrequency of coughing compared to breathing implies that TiBr likely contributes >90% of the daily aerosolised Mtb across a range of Cough frequencies. Conclusions: Our results suggest that, while Cough increases particle aerosolization compared to TiBr, this is not associated with increased Mtb aerosolization. Instead, TiBr produces more Mtb per particle than Cough. Assuming the number of viable Mtb organisms detected provides a proxy measure of patient infectiousness, these observations imply a significant contribution of TiBr to TB transmission.

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Section: Introductionmentioning

confidence: 84%

Section: Discussionmentioning

confidence: 99%

Section: Sample Collectionmentioning

confidence: 99%

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Aerosolization of Mycobacterium tuberculosis by tidal breathing

Dinkele

Gessner

McKerry

et al. 2021

Preprint

Self Cite

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“…16 The detection of Mtb bacilli or DNA in aerosols has been facilitated by the development of face masks, with capture filters or absorbent materials, or blow tubes with a capture filter. 37 , 38 , 39 Although capture methods are still under development, early results have been promising, suggesting high diagnostic yield (one study demonstrated 87% sensitivity when Ultra was used to analyse samples collected from face masks), and may identify patients with subclinical disease earlier than sputum-based sampling. 37 Furthermore, these methods can be applied to people before they cough: sampling aerosol from tidal breathing has yielded culturable Mtb bacilli, suggesting cough is not a transmission prerequisite.…”

Section: Overview Of Diagnostic Technologies and Tests By Specimen Typementioning

confidence: 99%

“… 37 Furthermore, these methods can be applied to people before they cough: sampling aerosol from tidal breathing has yielded culturable Mtb bacilli, suggesting cough is not a transmission prerequisite. 39 Detection of Mtb in expelled aerosols may thus play a role in identifying early disease, thought to be important for transmission, 41 and assessment of treatment response (important for infection control); however, this technology remains early stage.…”

Section: Overview Of Diagnostic Technologies and Tests By Specimen Typementioning

confidence: 99%