On October 13, officials with the U.S. Centers for Disease Control (CDC) warned that bacteria may have contaminated special devices used during open heart surgery, putting more than half a million heart surgery patients at risk. 
The devices, LivaNova PLC (formerly Sorin Group Deutschland GmbH) Stockert 3T heater-cooler devices, might have been contaminated with Mycobacterium chimaera bacteria during manufacturing, according to the CDC. 
In a news release, the agency said that people who have had open heart surgery should seek immediate medical care if they develop any signs of infection, including night sweats, muscle aches, weight loss, fatigue, or unexplained fever.
Additionally, the CDC said that doctors and hospitals should identify and inform patients who might have been put at risk.
Dr. Michael Bell, deputy director of the CDC’s Division of Healthcare Quality Promotion, said:
“It’s important for clinicians and their patients to be aware of this risk so that patients can be evaluated and treated quickly.
“Hospitals should check to see which type of heater-coolers are in use, ensure that they’re maintained according to the latest manufacturer instructions, and alert affected patients and the clinicians who care for them.”
The heater-cooler devices are used in more than 250,000 heart bypass procedures each year. The devices use water to help keep a patient’s blood circulating and organs at a specific temperature during surgery. The water does not come into contact with the patient, but bacteria can be transmitted through the air from the device’s exhaust vent.
“Some smart engineer designed it because surgeons said they need to keep this cool and that warm. But no one probably said, it needs not to have a fan because it wasn’t part of the calculation. The person who wanted this machine, they weren’t thinking about maintenance and repair.” 
Contaminated Stockert 3T heater-cooler devices infected at least 12 individuals at a hospital in York, Pennsylvania, last year. Six of the individuals died, though officials initially said they weren’t positive that infection was the primary cause of the deaths. 
The infection was identified at other hospitals, as well, and DNA testing confirmed the presence of the bacteria.
Risk is Low
Fortunately, the risk of infection is very low, according to Bell – from about 1 in 100 to 1 in 1,000 in hospitals where at least 1 infection had been identified. However, the CDC said:
“Although thousands of patients in the United States have been notified regarding potential exposure to contaminated heater-cooler devices, the number who were exposed might be much larger.” 
Rather than stop using the Stockert 3T heater-cooler devices, the CDC is simply recommending that healthcare workers and patients be aware of the potential for contamination. 
Mycobacterium Chimaera isn’t the Worst Bacteria Around – If You’re Healthy
Mycobacterium chimaera, also known as nontuberculous mycobacterium, or NTM, is found in nature and is not usually harmful for people with normal immunity; however, it can cause serious illness and death in people who are seriously ill or have compromised immune systems. The infection is slow-growing, and can worsen over the course of months or years. It is treatable, if caught in time.
Several individuals were diagnosed with the infection in Europe. Some of them sickened there were diagnosed almost 4 years after surgery. 
Surgical devices have been implicated in past infection outbreaks. An outbreak of Carbapenem resistant enterobacteriaceae, or CRE, spread by endoscopes, infected people in 42 states. The superbug can kill up to half of infected people who get bloodstream infections.
In the case of the endoscopes, the contamination was found to be caused by improper sterilization procedures. The devices were notoriously difficult to clean thoroughly.
Additionally, contaminated colonoscopes, devices used to perform colonoscopies, put nearly 300 people at a Massachusetts hospital at risk for HIV and hepatitis, due also to improper sterilization procedures.