870 - Mycobacterium chimaera Outbreak: Infection Control and Clinical Experiences in Edmonton, Alberta

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Presenting Author(s)

Brittany E. Kula

Resident Physician
University of Alberta
Edmonton, Alberta, Canada
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.

Co-Author(s)

SS

Stephanie Smith

Infectious Disease Staff
University of Alberta

Background: Mycobacterium chimaera is responsible for a global outbreak due to contaminated heater-cooler units (HCUs) used in cardiothoracic surgery and has been associated with high mortality. Optimal treatment is not known. The objectives of this study were to describe the Infection Control strategies utilized by the University of Alberta hospital and Mazankowski Heart Institute (MAZ) prior to availability of new HCUs, and outline the clinical course of locally acquired M. chimaera infection.

Methods: We reviewed interventions undertaken to mitigate the risk of M. chimaera infection. Any MAZ patient with M. chimaera isolated at an anatomic site with a history of cardiothoracic surgery from 2012-present were identified. Charts were reviewed for patient and infection characteristics.

Results: All manufacturer’s instructions for HCU cleaning-disinfection were followed. The MAZ was compliant with CDC recommendations for directing HCU ventilation exhaust away from the surgical field and to the use of filtered water. M. chimaera was isolated in 3/8 local HCUs. After decontamination procedure, 1 HCU grew M. chimaera but cleared after a second attempt. Smoke studies demonstrated aerosolization of HCU exhaust in October 2016 therefore the laminar air curtains were manipulated for increased flow in October and November 2016. By June 2017, HCUs were retro-fitted and in late 2017 all pre-2014 Sorin HCUs were replaced.
10 patients have been diagnosed with M. chimaera infection post-cardiothoracic surgery performed at the MAZ. None occurred after manipulation of the laminar air curtain. Mean patient age at time of cardiothoracic surgery was 62.3 years and 6 were male. All had implantation of prosthetic material. The most common culture-positive sites were blood in 9/10, urine in 5/10 and prosthetic material or surgical site in 3/10. 6/10 have died due to infection and mean life expectancy of those deceased from first positive culture is 123 days. An additional survivor has been transitioned to comfort care and lost to follow-up.

Conclusion: M. chimaera post cardiothoracic surgery has been challenging from an infection control perspective but the risk appears to have been mitigated through manipulation of the laminar air curtain. Locally, M. chimaera has been associated with significant (60%) mortality.