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State of California—Health and Human Services Agency
California Department of Public Health

AFL 16-16
November 28, 2016

General Acute Care Hospitals

Mycobacterium chimaera Infections Associated with Exposure to Sorin Stockert 3T Heater-Cooler Devices during Open Chest Cardiac Surgery
(This AFL supersedes and rescinds AFL 16-14)

AUTHORITY:     Title 17 California Code of Regulations (CCR) section 2500(a)(22); Title 22 CCR section 70737(a)

All Facilities Letter (AFL) Summary

This AFL supersedes AFL 16-14 and provides an update on the investigation of an unusual infection due to Mycobacterium chimaera (M. chimaera) after exposure to a specific type of heater-cooler device during open chest cardiac surgery. Per Title 17 CCR section 2500(a)(22) and Title 22 CCR section 70737(a), suspected or confirmed cases of this unusual infection must be reported to the California Department of Public Health (CDPH) and the local health department.


CDPH recently received reports of two patients with M. chimaera infection who underwent cardiothoracic surgery using a Sorin Stockert 3T heater-cooler device in a California hospital in 2014 and 2015. Invasive infections due to the slow-growing nontuberculous mycobacteria (NTM) M. chimaera have been identified in patients in Europe and the United States after open chest surgery using the Sorin Stockert 3T heater-cooler device manufactured by LivaNova PLC (formerly Sorin Group Deutschland GMbH). These M. chimaera infections have been diagnosed up to four years after surgery. Manifestations of M. chimaera clinical infection following cardiac surgery include sternal wound infections, endocarditis, osteomyelitis, disseminated granulomatous disease, and persistent bacteremia.

Heater-cooler devices are used in operating rooms with life-saving cardiopulmonary bypass machines to control core body temperature during cardiac surgery. The devices have closed water circuits that do not come into contact with the patient. Investigation has confirmed that the heater-cooler device can aerosolize particles and transmit mycobacteria from a contaminated heater-cooler device to the operative field.

Physicians should consider the possibility of M. chimaera infection when evaluating and treating patients who have had open chest surgery and consult an infectious disease specialist. Diagnosis of mycobacteria infection requires specific stains and cultures (e.g., acid fast bacillus (AFB) staining). Diagnosis of M. chimaera infection may be delayed or missed if specific tests for mycobacteria are not ordered. In addition, M. chimaera is part of the mycobacterium avium complex (MAC). Specialized testing is needed to specifically identify M. chimaera in the laboratory.

FDA Recommendations

On October 13, 2016, the Food and Drug Administration (FDA) issued a Safety Alert (replacing the June 1, 2016, Safety Alert) indicating that 3T devices manufactured prior to September 2014 may have been contaminated with M. chimaera during the manufacturing process and that 3T devices manufactured after September 2014 have also tested positive for M. chimaera.(1) Updated FDA recommendations to health care facilities and staff using 3T devices include (but not limited to):

  • Immediately remove from service any heater-cooler devices, accessories, tubing, and connectors that have tested positive for M. chimaera or have been associated with known M. chimaera patient infections at your facility.
  • Use new accessories, tubing, and connectors to prevent recontamination when using a different heater-cooler device. 
  • Be aware that device contamination also may occur from other sources such as environmental contamination or device contact with contaminated accessories.
  • Be aware that heater-cooler devices are important in patient care. In appropriately selected patients, the benefits of temperature control during open chest cardiothoracic procedures generally outweigh the risk of infection transmission associated with the use of these devices.
  • Be aware that testing of heater-cooler devices to identify units contaminated with M. chimaera presents technical challenges related to sample collection, the long culture time, and the high rate of false negative tests; therefore, it is not recommended at this time.
  • For facilities with 3T devices manufactured prior to September 2014, strongly consider transitioning away from the use of these devices for open-chest cardiac surgery until the manufacturer has implemented strategies for these devices to mitigate the risks of patient infection. Use of these devices should be limited to emergent and/or life-threatening situations if no other heater cooler devices are available.

The FDA also recommends that healthcare facilities and staff using any type of heater-cooler device (including the 3T) continue to follow all recommendations in the October 15, 2015, FDA Safety Communication. Recommendations include (but not limited to):

  • Strictly adhere to the cleaning and disinfection instructions provided in the manufacturer’s device labeling. Ensure you have the most current version of the manufacturer’s instructions for use readily available to promote adherence.
  • Do not use tap water to rinse, fill, refill or top-off heater-cooler water tanks since this may introduce NTM organisms. Use only sterile water or water that has been passed through a filter of less than or equal to 0.22 microns. When making ice needed for patient cooling during surgical procedures, use only sterile water or water that has been passed through a filter of less than or equal to 0.22 microns.
  • Direct the heater-cooler’s vent exhaust away from the surgical field to mitigate the risk of aerosolizing heater-cooler tank water into the sterile field.
  • Establish regular cleaning, disinfection and maintenance schedules for heater-cooler devices according to the manufacturer’s instructions to minimize the risk of bacterial growth and subsequent patient infection.
  • Immediately remove from service heater-cooler devices that show discoloration or cloudiness in the fluid lines/circuits, which may indicate bacterial growth. Consult your hospital infection control officials to perform the appropriate follow up measures and report events of device contamination to the manufacturer.

CDC Recommendations

On October 13, 2016, the Centers for Disease Control and Prevention (CDC) distributed a Health Advisory to hospitals to alert patients at risk from contaminated 3T heater-cooler devices.(2) CDC recommendations include:

  • Hospitals performing open-chest cardiac surgery should immediately assess their use of heater-cooler devices and determine whether they are currently using (or have previously used) 3T devices. Facilities should ensure that they are implementing current FDA recommendations to minimize patient risk to infections associated with heater-cooler devices.(3)
  • Hospitals should notify cardiothoracic surgeons, cardiologists, infectious disease physicians, internists, primary care physicians, and other clinicians who evaluate patients that have had open-chest cardiac or other bypass surgery, about the risk of infection associated with 3T heater-cooler devices. The CDC has sample letters available at CDC - Infection: Heater-Cooler.
  • Hospitals should review their facility’s microbiology laboratory database and records of surgical procedures for any positive NTM cultures in surgery patients that might indicate a possible case. The CDC has provided guidance on case-finding: CDC - Guidance on Case Finding.
  • Hospitals should consider institution-specific strategies for alerting patients of the risk of infection related to potentially contaminated heater-cooler devices. The CDC has sample patient notification letters available at CDC HAI: Heater-Cooler Infection. (On November 1, 2016, the CDC further clarified that hospitals consider notifying patients in writing if they were exposed to the 3T devices during open-chest cardiac surgery at their institution since January 1, 2012. Hospitals that did not use the 3T device during this entire time period should adjust the patient notification timeframe accordingly).(4)
  • Hospitals can consider prospective surveillance of patients who have undergone open-chest cardiac surgery involving a 3T heater-cooler device.
  • Hospitals should consider using informed consent to educate patients of the potential NTM infection risk.
  • The overall risk of M. chimaera infection is low relative to other complications following cardiac surgery; emergent cardiac procedures should not be delayed because of the use of 3T devices. Continued use of 3T devices should be done in accordance with the latest manufacturer’s recommendations, including maintenance and proper positioning of devices to minimize the risk of patient exposure.
  • Hospitals that have identified contaminated 3T heater-cooler devices or patient infections associated with devices should promptly alert their local or state health department and submit a report to FDA via MedWatch at: FDA: How to Report

CDPH Recommendations

CDPH recommends that hospitals performing open chest cardiac surgery 1) determine whether they are using, storing, or previously used one or more 3T heater-cooler units, 2) ensure that perfusionists and other staff are following FDA recommendations for the use and maintenance of 3T devices to reduce exposure risks and develop a plan to transition away from the 3T device, and 3) notify clinicians and patients using current CDC guidance. CDPH also recommends providing this information to infectious disease physicians, cardiologists, and other primary care clinicians who may provide follow-up care to patients in the years after cardiothoracic surgery.

Health care providers who suspect M. chimaera infection and clinical laboratories that identify MAC in a patient with a history of open chest cardiac surgery should contact the local health authority and CDPH for additional testing guidance and referral to a reference laboratory for confirmatory testing. In accordance with Title 17 CCR section 2500(a)(22), suspected or confirmed M. chimaera infections must be reported to the local health authority and CDPH.

For questions regarding the content of this AFL, please contact the CDPH Healthcare-Associated Infections Program at (510) 412-6060.



Original signed by Jean Iacino

Jean Iacino
Deputy Director




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