PUBLIC HEALTH COMMUNIQUE - NTM infection (8 September 2016)

Clinical Guidance for Physicians regarding patients at risk of NTM infection

This information is intended to provide clinical advice to general practitioners and specialists caring for patients who have undergone open cardiac surgery regarding potential infection from nontuberculous mycobacteria (NTM) acquired during valve replacement / repair or mediastinal vascular graft insertion between 1 October 2011 and August 2016.

Background

There have been a number of clusters of Mycobacterium chimaera infections (predominately prosthetic valve endocarditis (PVE)) reported in multiple countries. Disseminated disease without obvious endocarditis may also occur. These infections have been associated with cardiac surgery that has involved the use of Heater Cooler Units (HCUs) and Extra-Corporeal Membrane Oxygenation (ECMO).

HCUs are used during cardiopulmonary bypass required to perform open heart surgery. HCUs regulate temperature. While they do not come into contact with the patient, the cause of the infection appears to be linked to biofilm that develops inside the unit, allowing growth of Mycobacteria. The Mycobacterium is subsequently aerosolised into the environment by a unit fan during HCU use. This is due to a combination of issues including some aspects of the design and manufacture of the HCUs. The initial theory was that the infections were due to cleaning processes which facilitated the growth of biofilm, and the manufacturer subsequently revised the disinfection and maintenance procedure instructions accordingly. A recent article by Haller et al published in Euro Surveillance on 28 April 2016, is suggesting a possible point source contamination. This would explain why all clinical cases reported to date have involved the single species, M. chimaera.

M.chimaera is an uncommon cause of NTM infection in Queensland. It is a member of the “MAC” complex organism and not routinely identified to species level.

The full Health Professional fact sheet can be downloaded below, which outlines:

  • Risk
  • Initial patient assessment
  • Patient assessment for Mycobacterial PVE or disseminated disease
  • Patient treatment
  • Patient referral and notification

Please also share the FAQ for Patients sheet with patients who are at risk of or who have NTM infection to assist with outlining the diseases, symptoms and signs and other facts.