title: Real-Time Investigation of Tuberculosis Transmission: Developing the Respiratory Aerosol Sampling Chamber (RASC).
abstract: Knowledge of the airborne nature of respiratory disease transmission owes much to the pioneering experiments of Wells and Riley over half a century ago. However, the mechanical, physiological, and immunopathological processes which drive the production of infectious aerosols by a diseased host remain poorly understood. Similarly, very little is known about the specific physiological, metabolic and morphological adaptations which enable pathogens such as Mycobacterium tuberculosis (Mtb) to exit the infected host, survive exposure to the external environment during airborne carriage, and adopt a form that is able to enter the respiratory tract of a new host, avoiding innate immune and physical defenses to establish a nascent infection. As a first step towards addressing these fundamental knowledge gaps which are central to any efforts to interrupt disease transmission, we developed and characterized a small personal clean room comprising an array of sampling devices which enable isolation and representative sampling of airborne particles and organic matter from tuberculosis (TB) patients. The complete unit, termed the Respiratory Aerosol Sampling Chamber (RASC), is instrumented to provide real-time information about the particulate output of a single patient, and to capture samples via a suite of particulate impingers, impactors and filters. Applying the RASC in a clinical setting, we demonstrate that a combination of molecular and microbiological assays, as well as imaging by fluorescence and scanning electron microscopy, can be applied to investigate the identity, viability, and morphology of isolated aerosolized particles. Importantly, from a preliminary panel of active TB patients, we observed the real-time production of large numbers of airborne particles including Mtb, as confirmed by microbiological culture and polymerase chain reaction (PCR) genotyping. Moreover, direct imaging of captured samples revealed the presence of multiple rod-like Mtb organisms whose physical dimensions suggested the capacity for travel deep into the alveolar spaces of the human lung.
authors.affiliation: Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.|Desmond Tutu HIV Centre, IDM, University of Cape Town, Cape Town, South Africa.
authors.forename: Robin
authors.initials: R
authors.lastname: Wood
authors.affiliation: Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.|Desmond Tutu HIV Centre, IDM, University of Cape Town, Cape Town, South Africa.
authors.forename: Carl
authors.initials: C
authors.lastname: Morrow
authors.affiliation: Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.|Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, US National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Clifton E
authors.initials: CE
authors.lastname: Barry
authors.affiliation: Zeteo Tech LLC, Ellicott City, Maryland, United States of America.
authors.forename: Wayne A
authors.initials: WA
authors.lastname: Bryden
authors.affiliation: Zeteo Tech LLC, Ellicott City, Maryland, United States of America.
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Call
authors.affiliation: RTI International, Research Triangle Park, North Carolina, United States of America.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Hickey
authors.affiliation: Aerosol Exposure Dimensions, Cary, North Carolina, United States of America.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Rodes
authors.affiliation: Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.|South African Tuberculosis Vaccine Initiative, Department of Paediatrics and Child Health, University of Cape Town, Cape Town, South Africa.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Scriba
authors.affiliation: Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.|Structural Biology Research Unit, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Blackburn
authors.affiliation: Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.|Structural Biology Research Unit, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
authors.forename: Chacha
authors.initials: C
authors.lastname: Issarow
authors.affiliation: Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.|Structural Biology Research Unit, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
authors.forename: Nicola
authors.initials: N
authors.lastname: Mulder
authors.affiliation: Structural Biology Research Unit, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Woodward
authors.affiliation: Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.|MRC/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, Cape Town, South Africa.
authors.forename: Atica
authors.initials: A
authors.lastname: Moosa
authors.affiliation: Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.|MRC/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, Cape Town, South Africa.
authors.forename: Vinayak
authors.initials: V
authors.lastname: Singh
authors.affiliation: Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.|MRC/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, Cape Town, South Africa.
authors.forename: Valerie
authors.initials: V
authors.lastname: Mizrahi
authors.affiliation: Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.|MRC/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, Cape Town, South Africa.
authors.forename: Digby F
authors.initials: DF
authors.lastname: Warner
mesh_terms: D000336:Aerosols / Q000032:analysis*; D006801:Humans; D009169:Mycobacterium tuberculosis; D010316:Particle Size; D014376:Tuberculosis / Q000635:transmission*
chemical_list: D000336:Aerosols