To the Editor: A recently published study by Falkinham (1) showed that 17 (46%) of 37 households were contaminated with nontuberculous mycobacteria (NTM) of the same species as those found in patients with lung disease and that 7 (41%) of 17 had the same DNA fi ngerprint as the patient. One patient's isolate from sputum matched the isolate found in the shower water. Therefore, the patient's lung disease was likely acquired by inhalation of aerosols while showering. An isolate from another patient matched the isolate found in tap water. If the patient drank the contaminated water, Mycobacteria avium may have reached the lungs by aspiration because 26% of patients with NTM lung disease have been found to experience gastroesophageal re. ux disease (GERD) (2). Even if none of these scenarios was present, however, NTM patient contamination of samples is still likely. Six of the 7 matching households had water heater temperatures <125°C, indicating a negative correlation between NTM growth and temperature. Most M. avium and M. intracellulare are killed in <5 seconds (3) when exposed to 70oC; thus, all NTM species would likely be killed a few seconds after water reached the boiling point
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