News Release

Heater-cooler devices blamed for global Mycobacterium chimaera outbreak

Cardiac surgery patients in various countries have been infected by M. chimaera

Peer-Reviewed Publication

Society for Healthcare Epidemiology of America

NEW YORK (November 14, 2016) - A global outbreak of Mycobacterium chimaera, an invasive, slow-growing bacterium, is linked to heater-cooler devices (HCD) used in cardiac surgery, according to a study published today in Infection Control & Hospital Epidemiology, the journal of the Society for Healthcare Epidemiology of America. This study adds interim guidance to recent field reports on the outbreak, providing precautionary recommendations to hospitals and health systems to reduce the risk of infections.

"It is surprising that a global outbreak like this could go unnoticed for years. This dangerous infection has put many patients at risk all over the world," said Rami Sommerstein, MD, of Inselspital, Bern University Hospital in Switzerland, the lead author of the study. "Now that we know HCDs are the source, individual action from the different players (healthcare institutions, manufacturers, etc.) is needed to contain the ongoing patient risk. The most important action a hospital can take is to remove contaminated HCDs from the operating room and other critical areas. That is the only way to ensure that patients are protected from this infection moving forward."

HCDs are stand-alone devices needed for heat exchange in heart-lung machines used in some 250,000 surgeries annually in the U.S., according to the Centers for Disease Control and Prevention. In response to an increasing number of infections, investigators looked into hospital water sources and found M. chimaera in HCD water circuits - specifically, in the LivaNova 3T HCD used in most hospitals around the world. They also found the bacteria in air samples during surgeries with LivaNova HCDs, suggesting transmission through air particles.

To prevent future cases of invasive M. chimaera infections, the researchers made the following recommendations for hospitals and health systems, as well as public health authorities, based on their personal experience with the outbreak:

  • Ensure strict separation of contaminated HCDs from air of critical medical areas
  • Educate clinicians on the risks for and dangers associated with M. chimaera
  • Screen patients who had open heart surgery, heart transplantation or those who were exposed to ventricular assist devices and demonstrate prolonged and unexplained fevers.

M. chimaera is a non-tuberculous mycobacterium that was previously known to cause lung infections. Invasive M. chimaera in cardiac surgery patients is particularly difficult to treat because it requires surgery and prolonged antibiotic therapy.

"While our understanding of the causes and the extent of the M. chimaera outbreak is growing, several aspects of patient management, device handling and risk mitigation still require clarification," said Sommerstein.


Rami Sommerstein, Peter Schreiber, Daniel Diekema, Michael Edmond, Barbara Hasse, Jonas Marschall, Hugo Sax. "Mycobacterium chimaera Outbreak Associated with Heater-Cooler Devices - Piecing the Puzzle Together." Web (November 14, 2016).

About ICHE

Published through a partnership between the Society for Healthcare Epidemiology of America and Cambridge University Press, Infection Control & Hospital Epidemiology provides original, peer reviewed scientific articles for anyone involved with an infection control or epidemiology program in a hospital or healthcare facility. ICHE is ranked 13th out of 158 journals in its discipline in the latest Web of Knowledge Journal Citation Reports from Thomson Reuters.

SHEA is a professional society representing physicians and other healthcare professionals around the world with expertise and passion in healthcare epidemiology, infection prevention, and antimicrobial stewardship. SHEA's mission is to prevent and control healthcare-associated infections, improve the use of antibiotics in healthcare settings, and advance the field of healthcare epidemiology. SHEA improves patient care and healthcare worker safety in all healthcare settings through the critical contributions of healthcare epidemiology and improved antibiotic use. The society leads this specialty by promoting science and research, advocating for effective policies, providing high-quality education and training, and developing appropriate guidelines and guidance in practice. Visit SHEA online at, and @SHEA_Epi

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