Innovative Technique for Detecting Airborne Tuberculosis Infection

Researchers from Karolinska Institutet, in collaboration with teams in South Africa, have explored a groundbreaking method for identifying infectious tuberculosis (TB) through analysis of exhaled air. Published in Open Forum Infectious Diseases, the study highlights the potential of this new approach to improve early detection of active TB cases directly in primary care settings.

Tuberculosis is primarily an airborne disease traditionally diagnosed by examining sputum—mucus coughed up from the lungs—which can be challenging for some patients to produce. To overcome this obstacle, scientists tested whether DNA from the TB bacterium could be found in aerosols, the tiny particles expelled when a person breathes out. They used an innovative device called TB Hotspot detectOR (THOR), which collects aerosols via electrostatic sampling, and analyzed these samples with the same molecular techniques used for sputum testing, such as Xpert MTB/RIF Ultra.

The study involved 137 adults showing respiratory symptoms in South African primary care clinics. Results showed that TB DNA was detectable in exhaled air in approximately 47% of individuals who tested positive through sputum analysis. The sensitivity of this aerosol detection was slightly higher—around 57%—among patients with high bacterial loads in their sputum. The specificity, or ability to correctly exclude those without the disease, was measured at 77%. This indicates that the method could serve as a useful screening tool, especially when sputum collection is difficult.

Dr. Jay Achar, a researcher involved in the study, emphasized the significance of these findings, noting that detecting TB directly from breath could streamline early diagnosis and help identify contagious individuals more efficiently. The research also observed that men with high bacterial levels were more likely to have detectable TB DNA in aerosols, while those with fever were slightly less likely to test positive through this method.

An additional noteworthy discovery was the presence of TB DNA in 30% of environmental samples taken within clinics, even after cleaning, which underscores the persistent risk of transmission in healthcare environments. Overall, this innovative approach offers promise for rapid, non-invasive detection of infectious TB, facilitating quicker intervention and potentially reducing disease spread.

For more details, see the original study by Jay Achar et al., titled "Detection of aerosolized Mycobacterium tuberculosis DNA from adults being investigated for pulmonary tuberculosis using an electrostatic sampler in a South African primary care setting" (2025).