Isolation of Non-Tuberculous Mycobacteria (NTM) from Household Water of Patients with NTM Pulmonary Disease.

Objective:This study aims to investigate the prevalence of NTM in household water in China and assess its potential role as a source of infection for NTM pulmonary disease, a crucial step for understanding and controlling the spread of this increasingly prevalent disease. Methods:To examine the prevalence of mycobacteria in household water, 500 mL water samples and swabs were collected from all taps of 19 patients' homes. The amplification of mycobacterial 16SrRNA with bacteriological identification was as a protocol to discriminate mycobacterial isolations from non- mycobacterial isolations. The 570bp 16SrRNA amplicon was sequenced and used to define mycobacterial species. Results:The mycobacteria isolated from clinical samples from 19 patients included M. intracellulare, M. avium, M. abscessus, and M. kansasii. NTM isolated from household water of patients included M. avium (1 case), M. abscessus (2 cases), M. kansasii (8 cases), M. gordonae (1 case), M. gilvum (1 case), M. fortuitum (1 case), M. porcinum (1 case). M. abscessus, M. kansasii, and M. avium causing human disease were isolated from household water. Though M. intracellulare was the predominant species isolated from patients with NTM pulmonary disease, it was not found in household water. In addition, our results revealed that NTM preferentially colonize in biofilm/sediment (75% of positive growths were from tap swab samples), indicating the significance of finding specific NTM species in household water in relation to the patients' conditions, or the lack of correlation between M. intracellulare in patients and its absence in household water. Conclusions:The isolation of pathogenic NTM species from household water underscores the critical role of water hygiene in preventing NTM pulmonary disease and highlights the need for targeted public health strategies.