Source of Pathogen Infection in Four Hospitalized Patients Identified

TUESDAY, March 14, 2023 (HealthDay News) -- Hospital tap water and ice can represent a source of infection for vulnerable patients, according to a study published online March 7 in the Annals of Internal Medicine.

Michael Klompas, M.D., M.P.H., from Harvard Medical School and the Harvard Pilgrim Health Care Institute in Boston, and colleagues describe the analysis and mitigation of a cluster of Mycobacterium abscessus infections in four cardiac surgery patients from Brigham and Women's Hospital in Boston.

The researchers confirmed homology among clinical isolates by whole-genome sequencing. Patients were admitted to different rooms during different periods but were on the same floor. No common operating machine rooms, ventilators, heater-cooler devices, or dialysis machines were found. Heavy mycobacterial growth in ice and water machines on the cluster unit was identified from environmental cultures, while little or no growth was seen in machines from the hospital's other inpatient towers. The presence of a genetically identical element in ice and water machines and in patient specimens was confirmed by whole-genome sequencing. A commercial water purifier with charcoal filters and an ultraviolet irradiation unit was identified leading to the ice and water machines in the cluster tower. In municipal source water, chlorine was present at normal levels but was not detected downstream of the purification unit. After high-risk patients were switched to sterile and distilled water and ice, water machine maintenance was intensified, and the commercial purification system was decommissioned, no further cases occurred.

"Our experience reaffirms the potential risks associated with tap water and ice in the care of vulnerable patients and the potential value of emerging initiatives to minimize susceptible patients' exposure to tap water and ice during routine care," the authors write.

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