The first full study suggests a link between Mycobacterium chimaera infection and contaminated heater-cooler units used during open-heart surgery

Mycobacterium chimaera (M. chimaera) is a respiratory infection

M. chimaera is one of a group of common slow-growing environmental organisms that sometimes cause respiratory infections or severe disease in people whose immune systems are in some way compromised. M. chimaera is frequently found in many day-to-day places such as soil and water.

Contaminated heater-cooler units

The first full report has identified contaminated heater-cooler units in Germany as the likely source of M. chimaera infection in 21 open-heart surgery patients in Switzerland, Germany, the Netherlands, and the UK, and a further 12 in the USA and Australia, according to a study in The Lancet Infectious Diseases journal (12 July 2017).

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Linked to open-heart surgery

Previous studies have suggested a link to contaminated heater-cooler units used during open-heart surgery, but until now, there has been no firm evidence linking the global outbreak to a source, whether at a production site or local hospitals.

Professor Stefan Niemann of the National Centre for Mycobacteria, Forschungszentrum Borstel, Germany, and co-author of the study says: “Our study closes the… gap and provides evidence that the international healthcare related M. chimaera outbreak can most likely be attributed to a point source.”

“Operating rooms and other hospital settings with patients at increased risk of infection should be devoid of such uncontrolled water sources,” adds Professor Dr Hugo Sax, University Hospital Zurich, Switzerland, and co-author of the study.

The authors note that they were not able to link individual patients to individual heater-cooler units. Whereas in total there was a large number of samples, there were relatively few samples taken from tap water, heater-cooler water, and air samples to reliably pinpoint exact transmission events.


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