Mycobacterium chimaera (M. chimaera) is an environmental non-tuberculous mycobacteria belonging to the Mycobacterium avium complex. It has been recognised as a cause of endocarditis, severe disseminated infection and chronic sternal wound infection in patients who have undergone cardiothoracic surgery.
M. chimaera may manifest many years after surgery undertaken on bypass. Investigations in multiple countries shows this is likely to be transmitted from heater cooler units, which are part of the cardiopulmonary bypass equipment.
The risk of infection is low and control measures are already in place. However, M. chimaera infection can have an insidious and non-specific presentation, is not always identified through conventional microbiology, and requires specific treatment.
As of 17 September 2019, there were 45 cases of M. chimaera infection following surgery on cardiopulmonary bypass, of which 25 were known to have died. The median interval between surgery and diagnosis is 23 months but ranges from less than 1 to 68 months.
Guidance for healthcare providers and health professionals