Benjamin Patterson1, Wayne Bryden2, Charles Call2, Andrea McKerry3, Bryan Leonard3, Ronnett Seldon3, Melitta Gqada3, Ryan Dinkele4, Sophia Gessner4, Digby F Warner5, Robin Wood6. 1. University of Amsterdam, Amsterdam Institute for Global Health and Development, Amsterdam, Netherlands. Electronic address: patterson.b@unic.ac.cy. 2. Zeteo Tech, USA. 3. Desmond Tutu HIV Centre, University of Cape Town, South Africa. 4. SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, South Africa. 5. SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, South Africa; Wellcome Centre for Infectious Disease Research in Africa, University of Cape Town, South Africa. 6. Desmond Tutu HIV Centre, University of Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, South Africa.
Abstract
BACKGROUND: Symptoms of infectious respiratory illnesses are often assumed to drive transmission. However, production and release of Mycobacterium tuberculosis (Mtb) bioaerosols is poorly understood. We report quantitation of Mtb exhaled during specific respiratory manoeuvres. METHODS: Direct capture of nascent bioaerosol particles and indirect collection of aged particles was performed in 10 healthy subjects. Indirect and direct capture of exhaled viable Mtb bacilli was compared in 38 PTB patients and directly captured viable Mtb during cough and bronchiole-burst manoeuvres in 27 of the PTB patients. RESULTS: Direct sampling of healthy subjects captured larger bioaerosol volumes with higher proportions of 2-5 μm particles than indirect sampling. Indirect sampling identified viable Mtb in 92.1% (35 of 38) of PTB patients during 60-min relaxed breathing, median bacillary count 7.5 (IQR: 3.25-19). Direct sampling for 10-min identified Mtb in 97.4% (37 of 38) of PTB patients with higher bacilli counts (p < 0.001), median 24.5 (IQR:11.25-37.5). A short 5-min sampling regimen of 10 coughs or 10 bronchiole-burst manoeuvres yielded a median of 11 (IQR: 4-17) and 11 (IQR: 7-17.5) Mtb bacilli, respectively (p = 0.53). CONCLUSIONS: Peripheral lung bioaerosol released through deep exhalations alone contained viable Mtb suggesting non-cough transmission is possible in PTB.
BACKGROUND: Symptoms of infectious respiratory illnesses are often assumed to drive transmission. However, production and release of Mycobacterium tuberculosis (Mtb) bioaerosols is poorly understood. We report quantitation of Mtb exhaled during specific respiratory manoeuvres. METHODS: Direct capture of nascent bioaerosol particles and indirect collection of aged particles was performed in 10 healthy subjects. Indirect and direct capture of exhaled viable Mtb bacilli was compared in 38 PTB patients and directly captured viable Mtb during cough and bronchiole-burst manoeuvres in 27 of the PTB patients. RESULTS: Direct sampling of healthy subjects captured larger bioaerosol volumes with higher proportions of 2-5 μm particles than indirect sampling. Indirect sampling identified viable Mtb in 92.1% (35 of 38) of PTB patients during 60-min relaxed breathing, median bacillary count 7.5 (IQR: 3.25-19). Direct sampling for 10-min identified Mtb in 97.4% (37 of 38) of PTB patients with higher bacilli counts (p < 0.001), median 24.5 (IQR:11.25-37.5). A short 5-min sampling regimen of 10 coughs or 10 bronchiole-burst manoeuvres yielded a median of 11 (IQR: 4-17) and 11 (IQR: 7-17.5) Mtb bacilli, respectively (p = 0.53). CONCLUSIONS: Peripheral lung bioaerosol released through deep exhalations alone contained viable Mtb suggesting non-cough transmission is possible in PTB.
Authors: Shima M Abdulgader; Anna O Okunola; Gcobisa Ndlangalavu; Byron W P Reeve; Brian W Allwood; Coenraad F N Koegelenberg; Rob M Warren; Grant Theron Journal: Respiration Date: 2022-06-27 Impact factor: 3.966
Authors: Ruvandhi R Nathavitharana; Alberto L Garcia-Basteiro; Morten Ruhwald; Frank Cobelens; Grant Theron Journal: EBioMedicine Date: 2022-03-23 Impact factor: 11.205