Hot-Tub–Associated Mycobacterial Infections in Immunosuppressed Persons

To the Editor: I read with interest the report by Mangione et al. regarding Mycobacterium avium infection in a Colorado family who used an inadequately sanitized hot tub (1). The authors noted that the source of the M. avium complex was not clear, although the reservoir did appear to have been the hot tub. Twenty years ago, I helped treat a patient with a local infection caused by M. fortuitum in his amputation stump (2). The patient had sat in his tub postoperatively three to four times per week. Although he had added disinfectants as recommended by the manufacturer, he had not cleaned the tub mechanically at any time during the incubation period of his infection. We recovered what appeared to be the same strain of M. fortuitum from the abscess on his amputation stump and specimens from the hot tub water and filter. However, we could not recover any mycobacteria from his or his neighbor’s tap water. Three years after our experience with this patient, M. chelonei was found to cause colonization of sputum of patients with cystic fibrosis after they had been treated in a hydrotherapy pool (3). Very recently, an outbreak of 110 cases of furunculosis was attributed to M. fortuitum contamination of a footbath at a nail salon (4). These experiences indicate the absolute need for careful cleaning of hot tubs. Not only are immunosuppressed patients at risk for atypical mycobacterial infections but even otherwise healthy persons may be susceptible.