Mycobacterium simiaeOutbreak Associated With a Hospital Water Supply

Abstract

Objective: Mycobacterium simiaeis found primarily in the southwestern United States, Israel, and Cuba, with tap water as its suspected reservoir. Our institution saw an increase inM. simiaeisolates in 2001. An investigation into possible contaminated water sources was undertaken.Design: Environmental cultures were performed from water taps in the microbiology laboratory, patient rooms, points in the flow of water to the hospital, and patients' homes. Patient and environmentalM. simiaewere compared by PFGE.Setting: Military treatment facility in San Antonio, Texas.Patients: All patients with cultures positive forM. simiaebetween January 2001 and April 2002. Medical records were reviewed.Results: M. simiaewas recovered from water samples from the hospital, patients' home showers, and a well supplying the hospital. A single PFGE clone was predominant among water isolates (9 of 10) and available patient isolates (14 of 19). There was an association between exposure to hospital water and pulmonary samples positive for the clonalM. simiaestrain (P= .0018). Only 3 of 22 culture-positive patients met criteria forM. simiaepulmonary disease. Of them, two had indistinguishableM. simiaestrains from tap water to which they were routinely exposed.Conclusions: This represents an outbreak ofM. simiaecolonization with one nosocomial infection. It is only the second time thatM. simiaehas been recovered from hospital tap water and its first presentation in municipal water. This study raises issues about the need and feasibility of eliminating or avoiding exposure toM. simiaefrom tap water.