Bacterial and host determinants of cough aerosol culture positivity in patients with drug-resistant versus drug-susceptible tuberculosis
Individuals living with tuberculosis who display few symptoms tend to be the most infectious, an analysis of the tiny cough droplets produced when people cough has found.
Strains of tuberculosis that are resistant to drugs are threatening efforts to control the disease.
A team led by researchers at the University of Cape Town tested for the presence of bacteria-containing particles in cough aerosol samples taken from 452 people with tuberculosis. They identified pathogens in around a third of the samples — with clinical features such as lower symptom score, stronger cough, shorter treatment duration and higher bacterial counts in sputum all predictive of test positivity.
Other characteristics — including bacterial strain lineage and genomic variants, as well as dormancy status — were not associated with the presence of bug-containing aerosols and thus degree of infectiousness.
The findings support targeting transmission-limiting health interventions towards patients who present with a cough but do not necessarily have severe symptoms.
- Nature Medicine 26, 1435–1443 (2020). doi: 10.1038/s41591-020-0940-2