Transmission of Mycobacterium chimaera from Heater-Cooler Units during Cardiac Surgery despite an Ultraclean Air Ventilation System

Emerg Infect Dis. 2016 Jun;22(6):1008-13. doi: 10.3201/eid2206.160045. Epub 2016 Jun 15.

Abstract

Heater-cooler units (HCUs) were recently identified as a source of Mycobacterium chimaera causing surgical site infections. We investigated transmission of this bacterium from HCUs to the surgical field by using a thermic anemometer and particle counter, videotape of an operating room equipped with an ultraclean laminar airflow ventilation system, and bacterial culture sedimentation plates in a nonventilated room. Smoke from the HCU reached the surgical field in 23 s by merging with ultraclean air. The HCU produced on average 5.2, 139, and 14.8 particles/min in the surgical field at positions Off, On/oriented toward, and On/oriented away, respectively. Culture plates were positive for M. chimaera <5 m from the HCU in the test room. These experiments confirm airborne transmission of M. chimaera aerosols from a contaminated HCU to an open surgical field despite ultraclean air ventilation. Efforts to mitigate infectious risks during surgery should consider contamination from water sources and airflow-generating devices.

Keywords: Mycobacterium chimaera; aerosols; airborne transmission pathway; bacteria; cardiac surgical procedures; cross infection; disease outbreaks; heater–cooler units; nontuberculous mycobacteria; surgical wound infection; tuberculosis and other mycobacteria.

MeSH terms

  • Bacterial Load
  • Cardiac Surgical Procedures / adverse effects*
  • Cross Infection / diagnosis
  • Cross Infection / microbiology
  • Cross Infection / transmission
  • Equipment Contamination*
  • Humans
  • Mycobacterium Infections, Nontuberculous / diagnosis
  • Mycobacterium Infections, Nontuberculous / microbiology*
  • Mycobacterium Infections, Nontuberculous / transmission*
  • Mycobacterium avium Complex*
  • Postoperative Complications*