Detection of airborne <i>Mycobacterium tuberculosis</i> complex in high-risk areas of health care facilities in Thailand

SETTING In high-risk areas (sputum collection room in a tuberculosis [TB] clinic, patient rooms in a TB ward, the emergency department and the bronchoscopy unit) in seven health care facilities located in central Thailand. OBJECTIVE To detect airborne Mycobacterium tuberculosis complex and other environmental parameters using the liquid impinger and real-time quantitative polymerase chain reaction (real-time qPCR) technique in high-risk areas. DESIGN Cross-sectional study. RESULTS M. tuberculosis was detected in 3 of 99 (3.0%, 95%CI 0.6-8.6) areas: one sputum collection room and one TB in-patient room in one facility and one sputum collection room in another facility. In these three areas, the M. tuberculosis copy number/m³ ranged from 9.6 to 1671. Lower air change rate ( -1 ), higher relative humidity (>65%), and contact with coughing patient(s) were more common in airborne M. tuberculosis -positive areas than in M. tuberculosis -negative areas. CONCLUSIONS Air sampling using a liquid impinger followed by real-time qPCR is effective for quantitative detection of airborne M. tuberculosis in high-risk areas. Our findings indicate TB risk among health care workers, and suggest that improved ventilation, enhanced appropriate cough etiquette and respiratory protection are needed to mitigate M. tuberculosis transmission. .