First Australian case of disseminated Mycobacterium chimaera infection post-cardiothoracic surgery

A 68 year old female patient was diagnosed with disseminated Mycobacterium chimaera infection 13 months following open cardiothoracic surgery that involved the insertion of a mitral annuloplasty ring. Multiple imaging modalities, including echocardiography and PET computed tomography, failed to demonstrate any definitive evidence of annuloplasty ring involvement, endocarditis or other focal infection. The patient was initially misdiagnosed with possible sarcoidosis, however bone marrow and blood cultures subsequently grew M. chimaera. The patient was treated with ethambutol, clarithromycin and moxifloxacin without surgical reintervention, and remains on therapy with negative blood cultures after 3 months of treatment. Whole genome sequencing (WGS) has shown the patient's isolate to be identical to isolates obtained from a heater cooler unit in use at the time of the index operation [11]. This is the first case report of M. chimaera infection linked to cardiothoracic surgery outside of the USA or Europe, and highlights the difficulties in diagnosing this emerging infection with significant public health implications.