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

Abstract

BackgroundIn 2012, a global outbreak of invasive Mycobacterium chimaera (M. chimaera) infection was identified in patients after cardiopulmonary bypass surgery. Investigations revealed the source to be heater-cooler unit (HCU) exhaust, with point-source contamination discovered at the LivaNova HCU manufacturing plant (London, UK). We report our experience with affected HCUs at a high-volume pediatric cardiac surgery center in the United States. MethodsA multidisciplinary 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 laboratory/culture data and infectious diseases consultation. ResultsCardiopulmonary bypass surgeries were performed in 4276 patients (median age: 2.1 years; range: 0-48.4 years) between October 2010 and October 2016. Call center volume was highest in the first 6 weeks after 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 computed tomography (n = 2), cardiac magnetic resonance imaging (n = 1), and pulmonary computed tomography (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. ConclusionsThrough a highly coordinated outreach effort, no patients have been found to have M. chimaera infection in the 6 years after exposure to contaminated HCUs. Ongoing vigilance for cases that may yet manifest is needed.