Invasive Nontuberculous Mycobacterial Infections among Cardiothoracic Surgical Patients Exposed to Heater–Cooler Devices1

Meghan M Lyman,Heather Moulton-Meissner,Allison Longenberger,Shane R Walker,Jeffrey R Miller,Minn M Soe,M Shannon Keckler,Joseph F Perz,Kiran M Perkins,Cheri Grigg,Cara Bicking Kinsey,Judith Noble-Wang,Emily Cooper

doi:10.3201/eid2305.161899

Abstract

Invasive nontuberculous mycobacteria (NTM) infections may result from a previously unrecognized source of transmission, heater–cooler devices (HCDs) used during cardiac surgery. In July 2015, the Pennsylvania Department of Health notified the Centers for Disease Control and Prevention (CDC) about a cluster of NTM infections among cardiothoracic surgical patients at 1 hospital. We conducted a case–control study to identify exposures causing infection, examining 11 case-patients and 48 control-patients. Eight (73%) case-patients had a clinical specimen identified as Mycobacterium avium complex (MAC). HCD exposure was associated with increased odds of invasive NTM infection; laboratory testing identified patient isolates and HCD samples as closely related strains of M. chimaera, a MAC species. This investigation confirmed a large US outbreak of invasive MAC infections in a previously unaffected patient population and suggested transmission occurred by aerosolization from HCDs. Recommendations have been issued for enhanced surveillance to identify potential infections associated with HCDs and measures to mitigate transmission risk.

Highlights

Invasive nontuberculous mycobacteria (NTM) infections may result from a previously unrecognized source of transmission, heater–cooler devices (HCDs) used during cardiac surgery
During spring 2015, investigators in Switzerland reported an outbreak of invasive infections with Mycobacterium chimaera, a distinct species within the NTM category M. avium complex (MAC), associated with contaminated heater–cooler devices (HCDs) used during cardiopulmonary bypass for cardiac surgery [16]
The rate of NTM-positive specimens was noticeably higher among cardiothoracic surgical patients (20 patients/10,000 surgeries) than the rates among patients in other common surgical categories, including general surgery (8 patients/10,000 surgeries; p = 0.04) and orthopedic surgery (5 patients/10,000 surgeries; p = 0.004)

Summary

Introduction

Invasive nontuberculous mycobacteria (NTM) infections may result from a previously unrecognized source of transmission, heater–cooler devices (HCDs) used during cardiac surgery. During spring 2015, investigators in Switzerland reported an outbreak of invasive infections with Mycobacterium chimaera, a distinct species within the NTM category M. avium complex (MAC), associated with contaminated heater–cooler devices (HCDs) used during cardiopulmonary bypass for cardiac surgery [16]. Given this finding and recent reports suggesting that HCDs are a potential risk factor for NTM infection, we conducted a case–control study to identify risk factors associated with invasive extrapulmonary NTM infections among patients who underwent cardiothoracic surgery at Wellspan York Hospital.

Results

Conclusion