Cluster of invasive Mycobacteria chimaera infections following cardiac surgery demonstrating novel clinical features and risks of aortic valve replacement

Abstract

There is a global outbreak of infections due to Mycobacterium chimaera associated with cardiac surgery. The most serious infections involve prosthetic material implantation, and all have followed surgical procedures involving cardiopulmonary bypass. We describe a cluster of four cases following cardiac surgery at a tertiary referral centre in Sydney, Australia. We report novel clinical findings, including haemolysis and kidney rupture possibly related to immune reconstitution inflammatory syndrome. The positive effect of corticosteroids on haemodynamic function in two cases and the failure of currently recommended antimicrobial therapy to sterilise prosthetic valve material in the absence of surgery despite months of treatment are also critically examined. Positron emission tomography was positive in two cases despite normal transoesophageal echocardiograms. The proportion of cases with M. chimaera infection after aortic valve replacement (4/890, 0.45%; 95% confidence interval 0.18–1.15%) was significantly higher than after all other cardiothoracic surgical procedures (0/2433, 0%; 95% confidence interval 0–0.16%).

Case of Mycobacterium chimaera vertebral osteomyelitis diagnosed 7 years after cardiac surgery

“…In an update to our previous communication, 1,2 we describe a seventh case of Mycobacterium chimaera infection following cardiac surgery at Prince of Wales Hospital (POWH) 7 years prior.…”

“…Genomic sequencing demonstrated 10 single-nucleotide polymorphisms (SNPs) difference between M. chimaera isolate from the surgical specimen and the strain cultured from the heater cooler unit (HCU) used at POWH in 2015. 1 The accumulation of these random SNPs was attributed to the extended interval of 7 years between exposure and diagnostic culture.…”

Disseminated Mycobacterium chimaera Following Open-Heart Surgery, the Heater–Cooler Unit Worldwide Outbreak: Case Report and Minireview

“…The combination of clarithromycin or azithromycin, rifampin, or rifabutin and ethambutol is the treatment regimen designed on the basis of that recommended for MAC lung disease (38). Antimicrobial susceptibility of M. chimaera strains isolated during the outbreak were fortunately all susceptible to clarithromycin and amikacin (3,39). Given the disseminated nature of HCU-related infections and the poor outcome, parenteral amikacin, and fluoroquinolones were added (24,40).…”

The global Mycobacterium chimaera outbreak

“…Following the first report in Switzerland many others were published in Germany ( 19), Australia (32,34,44)…”