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Volume 26, Number 3—March 2020

Invasive Mycobacterium chimaera Infections and Heater-Cooler Devices in Cardiac Surgery

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In Response: We would like to thank Lamagni et al. (1) for including additional cases from the period of 2008–2014 and for recalculating the UK cumulative incidence risk by matching our assessment. We agree that the observed 3 times higher risk in Switzerland of Mycobacterium chimaera infection for a patient undergoing heart valve surgery cannot be explained unambiguously. The most likely explanation is indeed increased awareness of the risk in Switzerland compared with other countries, potentially improving likelihood of investigation for mycobacterial infection. We think that the early formation of a national and interdisciplinary working group (M. chimaera Task Force), which included representatives of the involved (para-)medical disciplines, authorities, and professional associations, has contributed greatly to raising this awareness.

We want to emphasize that approximately half of the patients in Switzerland were treated for suspected sarcoidosis or other rheumatic diseases. It was via the active case-finding mechanisms that these cases were identified. Furthermore, we would like to point out that, since the publication of our report (2), only 1 case known to the task force has been identified in Switzerland (in a patient whose surgery was performed in 2014). This finding could indicate that the formation of the national task force not only increased awareness but also ensured that the remaining infectious risk was reduced to a minimum within a very short time.


Rami SommersteinComments to Author , Barbara Hasse, and Andreas F. Widmer
Author affiliations: Bern University Hospital, Bern, Switzerland (R. Sommerstein); University Hospital Zurich, Zurich, Switzerland (B. Hasse); Basel University Hospital, Basel, Switzerland (A.F. Widmer)



  1. Lamagni  T, Charlett  A, Phin  N, Zambon  M, Chand  M. Invasive Mycobacterium chimaera infections hand heater–cooler devices in cardiac surgery. Emerg Infect Dis. 2020;26:Mar [date cited]. DOIGoogle Scholar
  2. Sommerstein  R, Hasse  B, Marschall  J, Sax  H, Genoni  M, Schlegel  M, et al.; Swiss Chimaera Taskforce. Swiss Chimaera Taskforce. Global health estimate of invasive Mycobacterium chimaera infections associated with heater-cooler devices in cardiac surgery. Emerg Infect Dis. 2018;24:5768. DOIPubMedGoogle Scholar


Cite This Article

DOI: 10.3201/eid2603.191818

Original Publication Date: February 04, 2020

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Table of Contents – Volume 26, Number 3—March 2020


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Rami Sommerstein, Bern University Hospital, Department of Infectious Diseases, Freiburgstrasse, 3010 Bern, Switzerland

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Page created: February 20, 2020
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