Pilot study to detect airborne Mycobacterium tuberculosis exposure in a South African public healthcare facility outpatient clinic

Background: Airborne transmission of Mycobacterium tuberculosis remains an occupational health hazard, particularly in crowded and resource-limited healthcare settings. Aim: To quantify airborne M.tuberculosis in a busy outpatient clinic in Gauteng, South Africa. Methods: Stationary air samples and samples from healthcare workers (HCWs) were collected in the polyclinic and administrative block. Quantitative real-time polymerase chain reaction (PCR) was used to detect airborne M.tuberculosis. Walkthrough observations and work practices of HCWs were also recorded. Findings: In total, M.tuberculosis was detected in 11 of 49 (22.4%) samples: nine of 25 (36%) HCW samples and two of 24 (8.3%) stationary air samples. Samples from five of 10 medical officers (50%) and three of 13 nurses (23%) were positive. Repeat measurements on different days showed variable results. Most of the HCWs (87.5%) with positive results had been in contact with coughing patients and had not worn respiratory masks despite training. Conclusion: The use of air sampling coupled with quantitative real-time PCR is a simple and effective tool to demonstrate the risk of M.tuberculosis exposure. The findings provide an impetus for hospital management to strengthen infection prevention and control measures for tuberculosis.