Cough-generated aerosols of Mycobacterium tuberculosis: a new method to study infectiousness.
The concentration and size distribution of infectious aerosols produced by patients with pulmonary tuberculosis (TB) has never been directly measured. We aimed to assess the feasibility of a method that we developed to collect and quantify culturable cough-generated aerosols of Mycobacterium tuberculosis. Subjects were recruited from a referral hospital and most had multidrug-resistant TB. They coughed into a chamber containing microbial air samplers while cough frequency was measured during two 5-minute sessions. Cough-generated aerosol cultures were positive in 4 of 16 subjects (25%) with smear-positive pulmonary TB. There was a rapid decrease in the cough-generated aerosol cultures within the first 3 weeks of effective treatment. Culture-positive cough aerosols were associated with lack of treatment during the previous week (p = 0.007), and there was a trend in the association with cough frequency (p = 0.08). The size distributions of these aerosols were variable, but most particle sizes were in the respirable range. Quantification of viable cough-generated aerosols is feasible and offers a new approach to study infectiousness and transmission of M. tuberculosis and other airborne pathogens.
Fennelly
Kevin P
KP
Department of Medicine, Center for the Study of Emerging and Re-Emerging Pathogens, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, NJ 07103, USA. fennelkp@umdnj.edu
Martyny
John W
JW
Fulton
Kayte E
KE
Orme
Ian M
IM
Cave
Donald M
DM
Heifets
Leonid B
LB
D000336:Aerosols; D000391:Air Microbiology; D003371:Cough / Q000382:microbiology*; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D004784:Environmental Monitoring / Q000379:methods* / Q000592:standards; D062665:Epidemiological Monitoring; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D017720:Molecular Epidemiology; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D010316:Particle Size; D015203:Reproducibility of Results; D015983:Selection Bias; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology*; D018088:Tuberculosis, Multidrug-Resistant / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission*; D014397:Tuberculosis, Pulmonary / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission*
D000336:Aerosols; D004269:DNA, Bacterial