Waterborne Mycobacterium avium Infection

To the Editor. —  In a recently published article, du Moulin et al¹ studied hospital tap water for the presence of mycobacteria. Mycobacterium avium, a frequent opportunistic pathogen among patients with the acquired immunodeficiency syndrome (AIDS), was isolated from 41% of the sites investigated. Mycobacterium avium was isolated more frequently from hot water than from cold water and at higher concentrations.The authors suggested that potable hot water systems, by creating aerosols, could serve as environmental sources for M avium infection in AIDS patients, and proposed raising the temperature of hot water to decrease the concentration of mycobacteria and cautioning patients to avoid hot water aerosols by bathing instead of showering to reduce exposure to M avium.Such measures might be reasonable to consider if the pathogenesis and route of infection in AIDS patients were well established. However, it is not yet known whether disseminated M avium disease in