title: Prolonged Outbreak of Mycobacterium chimaera Infection After Open-Chest Heart Surgery.
abstract: BACKGROUND
  Invasive Mycobacterium chimaera infections were diagnosed in 2012 in 2 heart surgery patients on extracorporeal circulation. We launched an outbreak investigation to identify the source and extent of the potential outbreak and to implement preventive measures.
  
  
  METHODS
  We collected water samples from operating theaters, intensive care units, and wards, including air samples from operating theaters. Mycobacterium chimaera strains were characterized by randomly amplified polymorphic DNA polymerase chain reaction (RAPD-PCR). Case detection was performed based on archived histopathology samples and M. chimaera isolates since 2006, and the patient population at risk was prospectively surveyed.
  
  
  RESULTS
  We identified 6 male patients aged between 49 and 64 years with prosthetic valve endocarditis or vascular graft infection due to M. chimaera, which became clinically manifest with a latency of between 1.5 and 3.6 years after surgery. Mycobacterium chimaera was isolated from cardiac tissue specimens, blood cultures, or other biopsy specimens. We were able also to culture M. chimaera from water circuits of heater-cooler units connected to the cardiopulmonary bypass, and air samples collected when the units were in use. RAPD-PCR demonstrated identical patterns among M. chimaera strains from heater-cooler unit water circuits and air samples, and strains in 2 patient clusters.
  
  
  CONCLUSIONS
  The epidemiological and microbiological features of this prolonged outbreak provided evidence for the airborne transmission of M. chimaera from contaminated heater-cooler unit water tanks to patients during open-heart surgery.
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich.
authors.forename: Hugo
authors.initials: H
authors.lastname: Sax
authors.affiliation: Institute of Medical Microbiology, National Centre for Mycobacteria, University of Zurich.
authors.forename: Guido
authors.initials: G
authors.lastname: Bloemberg
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich.
authors.forename: Barbara
authors.initials: B
authors.lastname: Hasse
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich.
authors.forename: Rami
authors.initials: R
authors.lastname: Sommerstein
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich.
authors.forename: Philipp
authors.initials: P
authors.lastname: Kohler
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Achermann
authors.affiliation: Institute of Surgical Pathology.
authors.forename: Matthias
authors.initials: M
authors.lastname: Rössle
authors.affiliation: Division of Cardiac Surgery, University Hospital Zurich, Switzerland.
authors.forename: Volkmar
authors.initials: V
authors.lastname: Falk
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich.
authors.forename: Stefan P
authors.initials: SP
authors.lastname: Kuster
authors.affiliation: Institute of Medical Microbiology, National Centre for Mycobacteria, University of Zurich.
authors.forename: Erik C
authors.initials: EC
authors.lastname: Böttger
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich.
authors.forename: Rainer
authors.initials: R
authors.lastname: Weber
mesh_terms: D004269:DNA, Bacterial / Q000235:genetics; D004196:Disease Outbreaks; D004783:Environmental Microbiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D058889:Molecular Typing; D009165:Mycobacterium Infections, Nontuberculous / Q000453:epidemiology* / Q000382:microbiology; D009170:Nontuberculous Mycobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D011446:Prospective Studies; D019105:Random Amplified Polymorphic DNA Technique; D012189:Retrospective Studies; D013530:Surgical Wound Infection / Q000453:epidemiology* / Q000382:microbiology; D013903:Thoracic Surgery
chemical_list: D004269:DNA, Bacterial
keywords: Mycobacterium chimaera; infection control; nontuberculous mycobacteria; open-chest heart surgery; outbreak