Update - 30 November 2018 - Sixth case confirmed
A sixth patient, woman aged in her 60's who had heart valve replacement surgery at Prince of Wales Hospital in 2015 has been diagnosed with Mycobacterium chimaera infection. Genome sequencing evidence from her clinical samples strongly links her to five 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.
The other five other patients who had all undergone open heart surgery, which included heart valve surgery, at Prince of Wales Hospital in 2015 have all been diagnosed with this infection since 2017, and one patient has died.
Because M. chimaera are slow-growing bacteria, patients will need to remain alert for symptoms of infection for at least five years 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.
Update - 31 July 2018
A positive M. chimaera water test result has also been reported in a second open heart surgery machine at St George Hospital as part of regular testing, and this machine was immediately removed from service. This machine was manufactured after the period of concern for M. chimaera contamination but was in service at the hospital from April 2015, before the first affected machine was removed from service in August 2016. It had been tested every three months and all previous tests were negative for M. chimaera.
St George Hospital had immediately removed the first affected open heart surgery machine after it had tested positive for M. chimaera in August 2016. The hospital has continued to thoroughly test and clean their other open heart surgery equipment in accordance with the manufacturer’s instructions.
St George Hospital has now written to 146 additional patients who had open heart surgery at the hospital between August 2016 and April 2018 who may have been exposed to the second affected machine prior to its removal. The letter explains the symptoms of M. chimaera infection and encourages anyone with concerns to speak with their general practitioner.
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.
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.
Infection in cardiac surgery patients with M. chimaera has been associated with a particular heater-cooler device - the Stockert 3T made by Sorin (now known as LivaNova). This was first recognised in 2012 in Switzerland. These devices, are widely used around the world including Australia, are thought to have been contaminated during manufacture up until September 2014.
Cases of infection with M. chimaera infections after cardiac surgery have been reported from Switzerland, Germany, the Netherlands, England and the United States.
M. chimaera are slow-growing bacteria - infections have been diagnosed from months to up to several years after an open-heart surgery involving the implicated heater-cooler devices.
The Therapeutic Goods Administration (TGA) has provided alertson 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 February 2017.
The overall risk to individual patients is thought to be very low. Initial information suggests that patients who had prosthetic implants (such as heart valve replacements) during their cardiac surgery are at a higher risk than 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.
In December 2016, the South-Eastern Sydney Local Health District and Sydney Children’s Hospital Network (SCHN) wrote to people who had open heart surgery at the four affected public hospitals from January 2012 to August 2016.
Five NSW residents who had undergone open heart surgery at Prince of Wales Hospital in 2015, have been confirmed to have developed M. chimaera infections. Unfortunately, one of the patients died as a result of the infection, despite having the infected heart valve replaced and many months of special antibiotic therapy.
The infections in five NSW residents brings the total number of cases reported in Australia to date to seven, along with single cases reported in Queensland and Victoria.
Unfortunately, there is no test to tell if a patient has been exposed to the bacteria before symptoms of the infection develop.
The South Eastern Sydney Local Health District has recently re-sent their annual reminders to public patients who had high risk open heart surgery at their affected hospitals. NSW Health also recommends that private hospitals provide similar reminders to their patients. The Sydney Children’s Hospitals Network provides information to parents of children who had open heart surgery at the affected hospitals through their regular specialist follow-ups.
Further information for patients
Patients seeking further details can contact the following information lines:
- Sydney Children’s Hospital Network – 02 9845 3442 (8.00am – 5.00pm)
- South Eastern Sydney Local Health District –1800 875 526 (8.00am – 5.00pm).
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.
- 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.
- 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.
- 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) .
- 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).
- Chand et al. Insidious risk of severe Mycobacterium chimaera infection in cardiac surgery patients. Clinical Infectious Diseases (2016). Published online 7 Dec 2016. doi:10.1093/cid/ciw754.