Mycobacterium chimaera Outbreak Management and Outcomes at a Large Pediatric Cardiac Surgery Center

Abstract Background In 2012, a global outbreak of invasive Mycobacterium chimaera (M. chimaera) infection was identified in patients post-cardiopulmonary bypass (CPB) surgery. Investigations revealed the source to be heater-cooler unit (HCU) exhaust, with point-source contamination discovered at the LivaNova HCU manufacturing plant. We report our experience with affected HCUs at a high-volume pediatric cardiac surgery center in the United States. Methods A multi-disciplinary task force was established for outbreak management, including removing contaminated HCUs from service. Patients identified as exposed to affected HCUs were systematically contacted. A call center was created for patient/family inquiries, and symptomatic patients were assessed using an institutional triage protocol, including lab/culture data and infectious diseases consultation. Results CPB surgeries were performed in 4,276 patients (median age 2.1 years, range 0-48.4) between October 2010 and October 2016. Call center volume was highest in the first 6 weeks following patient notification, totaling 307 calls and yielding 70 clinical patient assessments. Presenting symptoms included fatigue (60%), fever (49%), night sweats (46%), myalgias (34%), and weight loss (24%). Among the 70 assessed patients, echocardiogram (n=30), cardiac CT (n=2), cardiac MRI (n=1), and pulmonary CT (n=1) did not reveal abnormalities suggestive of active infection. Infectious diseases consultation occurred in 23 (33%) patients. Acid fast bacilli blood cultures were obtained in 30 patients; all were negative. Conclusions Through a highly coordinated outreach effort, no patients have been found to have M. chimaera infection in the six years after exposure to contaminated HCUs. Ongoing vigilance for cases that may yet manifest is needed.