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By Gary Evans, AHC Media, Senior Staff Writer
The Centers for Disease Control and Prevention is alerting hospitals that patients who underwent open-heart surgery using a Stöckert 3T heater-cooler device may have been exposed to Nontuberculous Mycobacterium (NTM) chimaera, a rarely pathogenic bacteria that is capable of causing life-threatening infections in this particular situation.
“New information indicates that these devices, manufactured by LivaNova PLC (formerly Sorin Group Deutschland GmbH), were likely contaminated … during manufacturing,” the CDC states. “Hospitals should advise potentially exposed patients to seek medical care if they are experiencing symptoms such as night sweats, muscle aches, unexplained weight loss, fatigue, or unexplained fever.”
In an FDA advisory also issued Oct. 13, 2016, that agency stated:
“The 3T devices manufactured at this facility were distributed worldwide. In response to the M. chimaera findings in August 2014, the manufacturer added cleaning and disinfection procedures to the production line in September 2014. Samples taken at the same manufacturing facility, by the German Regulatory Authorities in July 2015 did not show M. chimaera, potentially indicating the contamination at the manufacturing facility had been resolved. Although the manufacturer of 3T devices added cleaning and disinfection procedures to the production line in September 2014, the FDA is now aware of some 3T devices manufactured after September 2014 which have tested positive for M. chimaera. It has not been confirmed whether these devices were contaminated at the manufacturing facility or became contaminated at the user facility. To date, the FDA is not aware of M. chimaera patient infections associated with 3T devices that were manufactured after September 2014.”
The CDC estimates that in hospitals where at least one infection has been identified, the risk of infection was between about 1 in 100 and 1 in 1,000 patients.
“Initial information suggests that patients who had prosthetic material implanted are at highest risk for NTM infections,” the CDC reports. “These infections are difficult to treat and delays in diagnosis further complicate patients’ clinical management. Therefore, it is imperative that patients and providers are informed about the risk of infection associated with use of the 3T device and the need for appropriate diagnostic evaluation to facilitate timely diagnosis and treatment.”
As previously reported in Hospital Infection Control and Prevention, heater-cooler devices are used during cardiac surgical procedures to warm and cool a patient’s blood during cardiopulmonary bypass. The units have a closed circuit system to circulate water, but can create an aerosol that is vented into the immediate environs by an exhaust fan. The heretofore obscure Nontuberculous M. chimaera — ubiquitous in soil and water but rarely pathogenic — appears to be perfectly adapted to take advantage of these conditions, collecting in water and biofilms before being aerosolized over the operating field and the open chest of the patient. Completing this dire equation is that the devices may be difficult to disinfect and continue using with confidence that a patient will not be exposed. The threat has been underscored by outbreaks in Europe and last year in Pennsylvania and Iowa.
“CDC in collaboration with National Jewish Health completed a whole-genome sequencing analysis and results demonstrate that M. chimaera isolates from patients with heater-cooler associated infections and from the 3T heater-cooler devices from several U.S. hospitals (in Pennsylvania and Iowa) are all highly related to each other,” the CDC concludes. “This evidence for likely point-source contamination of the 3T heater-cooler devices is consistent with recent reports from Europe matching of M. chimaera sequences from environmental isolates at the device production site in Germany and isolates from patients and devices in Europe.”
The CDC recommendations for healthcare providers and hospitals are summarized as follows:
1. Internists, infectious disease specialists, cardiologists, cardiothoracic surgeons, and other clinicians should suspect NTM infections among patients who have signs of infection and a history of open-chest cardiac surgery.
o Infections can take months to cause symptoms.
o Patients with NTM infections following cardiac surgery have presented with a variety of clinical manifestations. Common examples are endocarditis, surgical site infection, or abscess and bacteremia. Other clinical manifestations have included hepatitis, renal insufficiency, splenomegaly, pancytopenia, and osteomyelitis.
2. Diagnosis can be difficult due to the nonspecific presentation of illness and the slow growing nature of the bacteria.
o Physicians should consider consulting with an infectious disease specialist if caring for patients who have undergone an open-chest cardiac procedure and present with signs of infection.
o Cultures for acid fact bacilli (AFB) should be obtained as part of the evaluation.
o Other specialized testing to detect M. chimaera may be needed and further laboratory testing should be discussed and arranged in consultation with an infectious disease specialist or health department.
1. 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.
2. 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.
3. 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.
4. Hospitals should consider institution-specific strategies for alerting patients of the risk of infection related to potentially contaminated heater-cooler devices.
5. Hospitals can consider prospective surveillance of patients who have undergone open-chest cardiac surgery involving a 3T heater-cooler device.
6. Hospitals should consider using informed consent to educate patients of the potential NTM infection risk.
7. 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.
8. 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.
Gary Evans has written about infectious diseases, infection control and other healthcare issues for more than 25 years. His writing and reporting have been honored with five awards from the National Press Club in Washington, DC.