Study Links Mycobacterial Infections to Hospital Ice and Water Machines

Four surgical patients at a hospital in Boston contracted mycobacteria infections from a hospital water and ice machine, leading to three deaths and raising concerns about safety of hospital water purification systems.

In a case study published in the March 2023 issue of the Annals of Internal Medicine, researchers traced a cluster of deadly infections to a hospital’s water and ice machines infested with mycobacteria.

Researchers from Harvard Medical School and Harvard Pilgrim Health Care Institute in Boston conducted an analysis of the cluster infections and the subsequent investigation.

Infections Linked to Commercial Water Purifier

An investigation into the infections determined the four patients were admitted to Brigham and Women’s Hospital in Boston, Massachusetts for surgical procedures at different times and in different rooms, but were all on the same floor of the hospital. They all developed Mycobacterium abscessus infections after heart surgery and were diagnosed between March 2017 and October 2018.

Investigators determined the infected patients did not have common operating rooms, ventilators, heater-cooler devices, or dialysis machines. However, genomic sequencing linked bacterial specimens from patients to the floor’s water and ice machines.

The hospital had a commercial water purifier with charcoal filters and a UV irradiation unit, which researchers determined to be a modification to the water system, that led to the patient tower where the infections occurred. The two other patient towers had their own water purifying systems.

Investigators found high levels of mycobacteria and low levels of chlorine in the water and ice machines in the patient tower where the infections occurred, but not in machines in the other patient towers. This led to them switching all patients in that tower to sterile and distilled water, and eventually removing the commercial water purifier.

After these measures, and improved maintenance on the ice and water machines, no further cases developed. However, three of the four infected patients died as a result of their infections.

“Well-intentioned efforts to modify water management systems may inadvertently increase infection risk for vulnerable patients,” the researchers warned.

Mycobacterium Infection Risks

Mycobacterium is a type of fast-growing bacteria that is resistant to antibiotics, making the infections difficult to treat. It is distantly related to tuberculosis and leprosy but does not lead to those diseases. It is a common contaminant in water and soil and is responsible for many skin and soft tissue diseases and central nervous system infections.

Symptoms can include cough, fever, chills, fatigue, lack of appetite, weight loss, and coughing up blood. Those with weakened immune systems are at the most risk, in which cases the infections can be deadly.