Update - May 2022

A seventh patient, a man aged in his 80's who had heart valve replacement surgery at Prince of Wales Hospital in 2015 has been diagnosed with Mycobacterium chimaera infection. The onset of symptoms related to his infection started at least 3 years ago. Genome sequencing evidence from his clinical samples strongly links him to 6 other cases diagnosed following surgery at Prince of Wales Hospital, and to the worldwide outbreak of M. chimaera infection following exposure to the rare bacteria during open heart surgery.

Because M. chimaera are slow-growing bacteria, patients need to remain alert for symptoms of infection after their open heart surgery involving the affected equipment, particularly if surgery included implants, such as heart valves, and seek medical advice straight away if symptoms develop. To date, the longest time after surgery for an infection to be identified is 12 years, reported in a patient from Italy.

Which open-heart surgery patients need to be aware of this risk?

  • NSW Public Hospitals: Children’s Hospital at Westmead, Prince of Wales Hospital, Sydney Children’s Hospital, Randwick (January 2012 – August 2016), St George Hospital (January 2012 - April 2018)
  • NSW Private Hospitals: Newcastle Private (July 2014 – September 2016), Norwest Private (January 2012 – August 2016), Prince of Wales Private (January 2012 – August 2016), St George Private (January 2012 – January 2017), The Sydney Adventist Hospital, Wahroonga (between 22 January and 18 June 2015), Westmead Private (June 2014 – December 2016)
  • ACT: National Capital Private (November 2011-August 2016) and Canberra Hospital (July 2014 – November 2016)

As this is an international problem, patients who had cardiac surgery in other states or territories, or overseas could also have been exposed.

Background information

There is a risk that certain heater-cooler devices used in open-heart cardiac surgery may have been contaminated with a rare bacterium called Mycobacterium chimaera (or M. chimaera), and that exposure of patients to these units during cardiac surgery may lead to infections that can appear months to years after the surgery.

In 2015, a cluster of cardiac surgery patients with M. chimaera were reported from Switzerland (2). Related cases have subsequently been reported from Germany, the Netherlands, the United Kingdom, the United States and Australia.

M. chimaera infections in cardiac surgery patients have been associated with exposure to a particular heater-cooler device - the Stöckert 3T made by Sorin (now known as LivaNova​). These devices, which are widely used around the world, are thought to have been contaminated during manufacture up until September 2014.

M. chimaera are slow-growing bacteria and infections have been diagnosed from months to up to twelve years after open-heart surgery involving the implicated heater-cooler devices.

The Therapeutic Good​s Administration (TGA) has provided alerts​​on this issue and the Australian Commission on Safety and Quality in Health Care (ACSQHC) also issued new National Infection Control Guidance relating to heater-cooler devices , in March 2020.

The overall risk to individual patients is thought to be very low. There is a higher risk for patients who had prosthetic implants (such as heart valve replacements) during their cardiac surgery compared to those who did not receive implants.

In August 2016, NSW Health responded to international reports of infection in patients due to M. chimaera bacteria associated with open heart surgery machines by:

  • Replacing or removing from service the small number of these machines used in the only four affected public hospitals – Prince of Wales Hospital, St George Hospital, Children’s Hospital Westmead and Sydney Children’s Hospital Randwick
  • Issuing alerts to the community and doctors
  • Circulating new national control guidelines for the devices.

South-Eastern Sydney Local Health District contacted people who had open heart surgery at Prince of Wales and St George Hospitals during the potential risk periods. Reminder letters continue to be sent to these patients. NSW Health recommended that private hospitals provide similar reminders to their patients. The Sydney Children's Hospital Network provided information to parents of children who had open heart surgery at the affected hospitals through their regular specialist follow-ups.

Seven NSW residents who had open heart surgery at Prince of Wales Hospital in 2015 have been confirmed to have developed M. chimaera infections. Unfortunately, two of these people have subsequently died.

Information on cases in other States and Territories is available via the TGA Infections associated with heater-cooler devices alert.

Unfortunately, there is no test to tell if a patient has been exposed to the bacteria before symptoms of the infection develop.

Further information​ ​​for patients

Patients should talk to their specialist or general practitioner for further information.

Further information​ ​​for health care professionals

Further information for health facilities

​Further information for laboratories

Sterile site samples from patients with prosthetic valve endocarditis, mediastinitis, infective endocarditis, graft infection, sternal wound infection or other cardiac or other transplanted organ infection three or more months post-cardiothoracic surgery (highest risk is valve surgery) should be cultured for Mycobacteria in addition to standard bacterial culture.

Alternatively, infected tissue samples, after the assessment of M. chimaera infection risk, can be subjected to panbacterial 16S rDNA PCR which is available at the ICPMR-Pathology West.

Related publications​

  1. US Food and Drug Administration. Food and Drug Administration. FDA Executive Summary. Nontuberculous Mycobacterium (NTM) Infections Associated with Heater-Cooler Devices (HCD) during Cardiothoracic Surgery. June 2016.
  2. Sax H, Bloemberg G, Hasse B, et al. Prolonged Outbreak of Mycobacterium chimaera Infection After Open-Chest Heart Surgery. Clinical Infectious Diseases. 2015; 61 (1): 67-75. doi: http://dx.doi.org/10.1093/cid/civ198 .
  3. Haller S, Höller C, Jacobshagen A, et al. Contamination during production of heater-cooler units by Mycobacterium chimaera potential cause for invasive cardiovascular infections: results of an outbreak investigation in Germany, April 2015 to February 2016. Euro Surveillance. 2016;21(17). doi: http://dx.doi.org/10.2807/1560-7917.ES.2016.21.17.30215.
  4. Kohler et al. Healthcare-associated prosthetic heart valve, aortic vascular graft, and disseminated Mycobacterium chimaera infections subsequent to open heart surgery. European Heart Journal 2015; 36(40). doi: http://dx.doi.org/10.1093/eurheartj/ehv342 .
  5. Chand et al. Insidious risk of severe Mycobacterium chimaera infection in cardiac surgery patients. Clinical Infectious Diseases (2016). Published online 7 Dec 2016. doi: http://dx.doi.org/10.1093/cid/ciw754.
  6. Vendramin et al. Longest incubation period of Mycobacterium chimaera infection after cardiac surgery. Eur J Cardiothorac Surg. (2021). http://doi.org/10.1093/ejcts/ezaa292

Current as at: Wednesday 8 June 2022
Contact page owner: Communicable Diseases