3T Heater-Cooler Infections Reported in Australia and New Zealand

Published on March 15, 2017 by Sandy Liebhard

Contaminated 3T Heater-Cooler systems appear to be connected to Mycobacterium chimaera  (M. chimaera) infections among some open-heart surgery patients in Australia and New Zealand. According to a report from MedPage Today, new research also suggests that the infections share genetic pointers with similar outbreaks recently reported in Europe and the U.S.

3T Heater-Cooler Infections

Manufactured by LivaNova PLC (formerly Sorin Group USA), the 3T Heater-Cooler system is designed to warm and cool patients undergoing cardiothoracic surgery and other medical procedures. The U.S. Food & Drug Administration has recently issued several warnings for the 3T system, after it was discovered that some  devices may have become contaminated with M. chimaera while they were being manufactured in  Germany.

Outbreaks of M. chimaera reported among open-heart surgery patients in the U.S. and Europe have since been tied to 3T Heater-Coolers. This potentially  deadly-bacteria is slow growing and may not be detected until months after an individual has undergone surgery. Symptoms to watch for include:

• Night sweats
• Muscle aches
• Weight loss
• Unexplained fever
• Fatigue

M. chimaera infections linked to the 3T system have already prompted a number of heater-cooler lawsuit filings in U.S. courts. Plaintiffs pursuing these claims have asked the U.S. Judicial Panel on Multidistrict Litigation to centralize all federal cases in a single jurisdiction so that they may undergo coordinated pretrial proceedings. The Panel is to hear oral arguments on the matter during its March 30^th Hearing Session in Phoenix, Arizona.

Whole-Genome Sequencing of M. Chimaera Isolates in Australia, New Zealand

M. chimaera infections associated with 3T Heater-Coolers had already been reported in five countries in the Northern Hemisphere when researchers at the University of Melbourne in Australia decided to begin a search of their region. From May 2015 through July 2016, they collected a total of 48 M. chimaera isolates from across Australia and New Zealand, including five from patient samples and 43 from 3T heater-cooler units.

All isolates underwent whole-genome sequencing. Notably, an isolate from a patient who had previously undergone cardiac surgery was identical to two taken from a single heater-cooler unit used in the facility where the patient underwent surgery a second time. The genome was also a close match to M. chimaera reported in the Northern Hemisphere.

“Our observations highlight the potential for global dissemination of contaminated medical devices, including to regions such as Australia and New Zealand,” the investigative team wrote in a research letter published by The New England Journal of Medicine on February 9th. “These data show the value of combining high-resolution molecular analysis and public sharing of sequence data to improve responses to outbreaks that have potential public health importance.”