Special devices used during open heart surgery may have been contaminated with bacteria that puts patients at risk for life-threatening infections, U.S. health officials warned Thursday.

Some LivaNova PLC (formerly Sorin Group Deutschland GmbH) Stockert 3T heater-cooler devices, which are used during many open heart surgeries, might have been contaminated with Mycobacterium chimaera bacteria during manufacturing, the officials said.

People who have had open heart surgery should seek medical care if they have infection-related symptoms, such as night sweats, muscle aches, weight loss, fatigue or unexplained fever, the U.S. Centers for Disease Control and Prevention said in a news release.

The agency also said that hospitals and doctors should identify and inform patients who might have been put at risk.

“It’s important for clinicians and their patients to be aware of this risk so that patients can be evaluated and treated quickly,” said Dr. Michael Bell, deputy director of the CDC’s Division of Healthcare Quality Promotion.

“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,” he urged.

Each year in the United States, there are more than 250,000 heart bypass procedures that use heater-cooler devices. These devices help keep a patient’s circulating blood and organs at a specific temperature during surgery.

About 60 percent of heart bypass procedures utilize the heater-cooler devices that may have been contaminated with M. chimaera. In hospitals where at least one infection has been identified, the risk of a patient getting an infection from the bacteria was between about 1 in 100 and 1 in 1,000, the CDC said.

Current information suggests that patients who had valves or prosthetic products implanted have a higher risk of infection.

For more information, patients and doctors can call 800-CDC-INFO (800-232-4636).