Healthcare-associated mycobacterium chimaera transmission and infection prevention challenges: Role of heater-cooler units as a water source in cardiac surgery

An outbreak of invasive Mycobacterium chimaera infections associated with heater-cooler units (HCUs) during cardiac surgeries was first reported from Switzerland in 2015 [1], and the increasing reports of M. chimaera infections following cardiac surgeries using HCUs have raised a global public health concern [2, 3]. More than 250 000 cardiopulmonary bypass procedures with HCUs have been annually conducted in the United States, and thousands of patients exposed to potentially contaminated HCUs have been notified [4, 5]. In this issue of Clinical Infectious Diseases, Chand et al [6] describe patients in the United Kingdom involved in this outbreak; herein we discuss issues regarding the acquisition of healthcare- associated M. chimaera as well as infection prevention strategies.