Heater-cooler devices used in cardiac surgery - risk of infection with Mycobacterium species

(All manufacturers) Low risk of Mycobacterium infection in patients undergoing cardiac surgery, associated with heater-coolers used with cardiopulmonary bypass machines. Possible cause may be Mycobacterium-contaminated water in the heater-coolers (MDA/2015/022)


  • Follow the manufacturer’s instructions for use at all times, in particular for cleaning and disinfecting these devices and the sterile components used in the system.
  • Review, update and follow the local protocols for water management practices, water quality, environmental hygiene, vigilance, and maintenance of these devices.
  • Review, update and follow your local risk assessments for the safe operation of the heater-coolers.
  • Identify whether there are any practices which may lead to transmission of organisms via aerosolisation where there is water contact with other cardiac surgery equipment.
  • Have systems in place to notify the manufacturer and MHRA if you observe specific risks associated with the use of any of these devices.
  • Have systems in place to contact Public Health England (PHE), or in the case of the Devolved Administrations their respective health protection agencies, if you have new cases of mycobacteria infections.

Action by

All medical and nursing staff who use these devices or who are responsible for maintaining devices used in cardiac surgery.

Deadlines for action

Actions underway: 2 July 2015, actions complete: 6 August 2015

Problem/ background

A small number of patients who underwent cardiac surgery, where cardiopulmonary bypass was used, developed endocarditis and/or septicaemia associated with Mycobacterium avium species.

A study suggests that a possible source of contamination is colonisation by bacteria of the water used in the heater-coolers. Study Reference: Sax H, Bloemberg G, Hasse B, Sommerstein R, Kohler P, Achermann Y et al (2015). Prolonged outbreak of Mycobacterium chimaera infection after open-chest heart surgery. Clin Infect Dis Mycobacterium avium complex is usually described as causing respiratory infections and disseminated infections in immunocompromised patients. 

The overall risk of infection is difficult to quantify as current practices for monitoring the environmental integrity of operating theatres may not identify this slow-growing, resistant organism. It is important that you are aware of the mycobacteria risk to patients undergoing cardiac surgery.

For England: PHE issued a health protection report serial number 2015/020 in March 2015 to all microbiology and cardiothoracic centres to raise awareness of mycobacteria infection and for hospitals to undertake a local risk assessment of their cardiac bypass machines or devices using a water system. The original report and updates are on Public Health England’s website.

Additional information is available from PHE’s website.

For Scotland: Content of the PHE report was circulated in Scotland by Health Protection Scotland (HPS) – Reference 2015/008.

For Northern Ireland: The Public Health Agency (PHA) in a letter dated 24 March 2015 contacted trust microbiologists and the BHSCT Cardiothoracic Unit highlighting this issue and actions required. Contact the PHA duty room on 03005550119 for further information.

For Wales: Content of the PHE report and additional information was circulated to all Health Boards in Wales by Public Health Wales on 17 April.


If you are responsible for cascading these alerts in your organisation, these are our suggested distribution lists.


CAS and SABS (NI) liaison officers for onward distribution to all relevant staff including:

  • adult intensive care units
  • anaesthesia, directors of
  • anaesthetic medical staff
  • anaesthetic nursing staff
  • anaesthetists
  • cardiologists
  • cardiology departments
  • cardiology nurses
  • cardiology, directors of
  • cardiothoracic departments
  • cardiothoracic surgeons
  • cardiothoracic surgery directors
  • clinical governance leads
  • clinical governance leads
  • clinical perfusionists
  • health and safety managers
  • infection control departments
  • infection prevention and control directors
  • infectious diseases paediatricians
  • intensive care medical staff/paediatrics
  • intensive care nursing staff (adult)
  • intensive care nursing staff (paediatric)
  • intensive care units
  • intensive care, directors of
  • microbiologists
  • operating department practitioners
  • paediatric cardiologists
  • paediatric intensive care units
  • respiratory departments
  • risk managers
  • theatre managers
  • theatre nurses
  • theatres

NHS England area teams

CAS liaison officers for onward distribution to all relevant staff including:

  • practice managers

Independent distribution

Establishments registered with the Care Quality Commission (CQC) (England only):

  • hospitals in the independent sector
  • independent treatment centres
  • private medical practitioners

Please note: CQC and OFSTED do not distribute these alerts. Independent healthcare providers and social care providers can sign up to receive MDAs directly from the Department of Health’s Central Alerting System (CAS) by sending an email to: safetyalerts@dh.gsi.gov.uk and requesting this facility.



Send enquiries about this notice to MHRA, quoting reference number MDA/2015/022 or 2014/007/016/081/003.

Technical aspects

Enitan Taiwo and Andrew Bent, MHRA
Telephone: 020 3080 7122 / 6079

Email: enitan.taiwo@mhra.gov.uk or andrew.bent@mhra.gov.uk

Clinical aspects

Dr Neil McGuire
Telephone: 020 3080 6800

Email: neil.mcguire@mhra.gov.uk

Reporting adverse incidents in England

Through the Yellow Card website.

Northern Ireland

Alerts in Northern Ireland are distributed via the NI SABS system.

Enquiries and adverse incident reports in Northern Ireland should be addressed to:

Northern Ireland Adverse Incident Centre
CMO Group
Department of Health, Social Services and Public Safety
Telephone: 028 9052 3868
Fax: 028 9052 3900

Email: NIAIC@dhsspsni.gov.uk

Northern Ireland Adverse Incident Centre (NIAIC)

Reporting adverse incidents in Northern Ireland

Report directly to NIAIC using the forms on the website.


Enquiries and adverse incident reports in Scotland should be addressed to:

Incident Reporting and Investigation Centre
Health Facilities Scotland
NHS National Services Scotland
Telephone: 0131 275 7575
Fax: 0131 314 0722

Email: nss.iric@nhs.net

Reporting adverse incidents in Scotland

NHS boards and local authorities in Scotland should report to Health Facilities Scotland.

Contractors such as private hospitals carrying out NHS work and private care homes that accept social work funded clients should report to Health Facilities Scotland.

Private facilities providing care to private clients should report to the Care Inspectorate and MHRA.


Enquiries in Wales should be addressed to:

Healthcare Quality Division
Welsh Government
Telephone: 1267 225 278 / 02920 825 510

Email: Haz-Aic@wales.gsi.gov.uk

Reporting adverse incidents in Wales

Report to MHRA through Yellow Card and follow specific advice for reporting in Wales in MDA/2004/054 (Wales).

Download documents

MDA/2015/022 Heater-coolers

Published 11 June 2015