Global outbreak of M. chimaera contamination

Associated with water-based heater-cooler units used in cardiopulmonary bypass surgery

More than 120 cases of serious invasive M. chimaera infection due to contaminated HCUs reported worldwide.4

M. chimaera infection diagnosis is challenging because clinical manifestations can take months or years to develop and are often nonspecific.1,12

M. chimaera infections have a poor prognosis, with a 5-year mortality rate of approximately 50%.5

Decontamination procedures provided by the manufacturer do not sufficiently inhibit the growth of micro-organisms in HCUs and require use of toxic disinfectants.1,6,7,8,13

Due to the inadequacy of current disinfection regimens, recent guidelines recommend removal of water-based HCUs from the operating room.9

Infection treatment

Treatment of prosthetic-valve endocarditis in Germany exceeded €100,000 per patient in 10% of cases.10

Cleaning and disinfection costs

In one UK hospital, the extra cost of operating eight HCUs has been estimated at £34,391.54 per year.7

Construction costs for isolating HCUs

Costs for removal and construction of separate ‘ante-rooms’ for HCUs have been reported at between £6,158 -£28,444 in two UK studies.7,11

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Marra AR, Diekema DJ, Edmond MB. Mycobacterium chimaera Infections Associated With Contaminated Heater-Cooler Devices for Cardiac Surgery: Outbreak Management. Clin Infect Dis. 2017;65:669-674.


Hasse B, Hannan MM, Keller PM, et al. International Society of Cardiovascular Infectious Diseases Guidelines for the Diagnosis, Treatment and Prevention of Disseminated Mycobacterium chimaera Infection Following Cardiac Surgery with Cardiopulmonary Bypass. J Hosp Infect. 2020;104(2):214-235.


Acosta F, Perez-Lago L, Ruiz Serrano M, et al. Fast update of undetected Mycobacterium chimaera infections to reveal unsuspected cases. J Hosp Infect. 2018;100:451-455.    


Ninh A, Weiner M, Goldberg A. Healthcare-Associated Mycobacterium chimaera Infection Subsequent to Heater-Cooler Device Exposure During Cardiac Surgery. J Cardiothorac Vasc Anesth. 2017;31(5):1831-1835.


Garvey MI, Ashford R, Bradley CW, et al. Decontamination of Heater-Cooler units associated with contamination by atypical mycobacteria. J Hosp Infect. 2016;93(3):229-234.


Walker J, Moore G, Collins S, et al. Microbiological problems and biofilms associated with Mycobacterium chimaera in Heater-Cooler units used for cardiopulmonary bypass. J Hosp Infect. 2017;96(3):209-220.


Colangelo N, Giambuzzi I, Moro M, et al. Mycobacterium chimaera in Heater–Cooler units : new technical approach for treatment, cleaning and disinfection protocol. Perfusion. 2018:1-5.


Wahba A, Milojevic M, Boer C, et al. 2019 EACTS/EACTA/EBCP guidelines on cardiopulmonary bypass in adult cardiac surgery. Eur J Cardio-Thoracic Surg.2019;57(2):210-251.


Grubitzsch H, Christ T, Melzer C, Kastrup M, Treskatsch S, Konertz W. Surgery for prosthetic valve endocarditis: Associations between morbidity, mortality and costs. Interact Cardiovasc Thorac Surg. 2016;22(6):784-791.


Barker TA, Dandekar U, Fraser N, et al. Minimising the risk of Mycobacterium chimaera infection during cardiopulmonary bypass by the removal of Heater-Cooler units from the operating room. Perfusion. 2018;33(4):264-269.


Vendramin I, Peghin M, Tascini C et al. Longest incubation period of Mycobacterium chimaera infection after cardiac surgery. Eur J Cardiothorac Surg 2020


Ditommaso S, Giacomuzzi M, Memoli G et al. Failure to eradicate non-tuberculous mycobacteria upon disinfection of heater-cooler units: results of a microbiological investigation in northwestern Italy. Journal of Hospital Infection. 2020.