Global outbreak of severe Mycobacterium chimaera disease after cardiac surgery: a molecular epidemiological study.

BACKGROUND: Since 2013, over 100 cases of Mycobacterium chimaera prosthetic valve endocarditis and disseminated disease were notified in Europe and the USA, linked to contaminated heater-cooler units (HCUs) used during cardiac surgery. We did a molecular epidemiological investigation to establish the source of these patients' disease. METHODS: We included 24 M chimaera isolates from 21 cardiac surgery-related patients in Switzerland, Germany, the Netherlands, and the UK, 218 M chimaera isolates from various types of HCUs in hospitals, from LivaNova (formerly Sorin; London, UK) and Maquet (Rastatt, Germany) brand HCU production sites, and unrelated environmental sources and patients, as well as eight Mycobacterium intracellulare isolates. Isolates were analysed by next-generation whole-genome sequencing using Illumina and Pacific Biosciences technologies, and compared with published M chimaera genomes. FINDINGS: Phylogenetic analysis based on whole-genome sequencing of 250 isolates revealed two major M chimaera groups. Cardiac surgery-related patient isolates were all classified into group 1, in which all, except one, formed a distinct subgroup. This subgroup also comprised isolates from 11 cardiac surgery-related patients reported from the USA, most isolates from LivaNova HCUs, and one from their production site. Isolates from other HCUs and unrelated patients were more widely distributed in the phylogenetic tree. INTERPRETATION: HCU contamination with M chimaera at the LivaNova factory seems a likely source for cardiothoracic surgery-related severe M chimaera infections diagnosed in Switzerland, Germany, the Netherlands, the UK, the USA, and Australia. Protective measures and heightened clinician awareness are essential to guarantee patient safety. FUNDING: Partly funded by the EU Horizon 2020 programme, its FP7 programme, the German Center for Infection Research (DZIF), the Swiss National Science Foundation, the Swiss Federal Office of Public Health, and National Institute of Health Research Oxford Health Protection Research Units on Healthcare Associated Infection and Antimicrobial Resistance.

The elephant trunk technique: operative results in 100 consecutive patients.

OBJECTIVES: To describe morbidity and mortality in patients undergoing the elephant trunk (ET) implantation as the first stage in the repair of their mega aorta and to assess determinants for the occurrence of complications. METHODS: One hundred consecutive patients undergoing an ET implantation between 1984 and June 2001 were retrospectively analyzed. The ET was implanted as an extension of an isolated aortic arch (1%), an aortic valve replacement+ascending aorta+arch (14%), a root replacement+ascending aorta+arch (37%) and an ascending aorta+arch (48%). Indications for surgery were acute aortic dissection (1%), an inflammatory aneurysm (3%), chronic post-dissection (31%) or degenerative (65%) aneurysm. Marfan syndrome was present in six patients. For cerebral protection, we used isolated deep hypothermic circulatory arrest (7%), deep hypothermic circulatory arrest combined with uni- or bilateral antegrade cerebral perfusion (18%) or isolated uni- or bilateral antegrade cerebral perfusion (75%). Uni- and multivariate analysis was used. RESULTS: There were no intraoperative deaths. Hospital mortality was 8%. The causes of death were cardiac in one, rupture of a remote aneurysm in three, tamponade in one and sepsis in three. After multivariate analysis, no single factor emerged as a risk factor for hospital mortality. Permanent and transient neurologic dysfunction occurred in 4 and 2%, respectively. Univariate analysis showed the operative period before 1990 (P=0.029) and emergency (P=0.018) as significant factors for postoperative neurologic dysfunction; after stepwise logistic regression analysis, only emergent operation retained significance (P=0.005). Permanent hoarseness, total atrioventricular block requiring pacemaker implantation and re-thoracotomy for bleeding occurred in 17, 2 and 30%, respectively. CONCLUSIONS: The first step in the repair of a mega aorta, the implantation of an ET, can be performed with a low mortality and an acceptable morbidity. The risk of central neurologic damage is higher in emergency interventions.