As reports of severe infections following heart surgery continue to surface worldwide, new research suggests that more than one-third of all 3T Heater-Cooler Systems commonly used during cardiac procedures appear to be contaminated with Mycobacterium chimaera, which can cause hard-to-detect and difficult to treat infections that surface months or years later.
Researchers with Special Pathogens Laboratory announced that they tested 89 different 3T Heater-Cooler Systems between July 2015 and December 2016, and found that 33 of them were contaminated with M. chimaera. The findings were presented this week at the Annual Conference of the Association for Professionals in Infection Control and Epidemiology (APIC) and announced in an APIC press release on June 14.
Strains of M. chimaera and Mycobacterium abscessus (M. abscessus) have been linked to a growing number of infections worldwide that developed following open heart surgery, valve replacement, heart bypass and other cardiac procedures. Both are forms of non-tuberculosis mycobacteria (NTM) infections.
The heart surgery infections have been linked use of certain Sorin 3T Heater-Coolers, which are a medical device commonly found in operating rooms to regulate blood temperature. The devices are used in the vast majority of heart surgeries, but it was discovered last year that certain devices manufactured prior to September 2014 may be contaminated with a slow growing bacteria, which can cause life-threatening infections to surface months or even years after exposure.
Contaminated vapors may be released by the devices, posing a serious risk for individuals with a compromised immune system and open chest cavity during the surgery, leading to multiple reports of Mycobacterium chimaera or Mycobacterium abscessus infections.
At the Conference, John Rihs, VP of Laboratory Services at Special Pathogens Laboratory announced that their researchers tested 653 water samples from 89 units from 23 different hospitals in 14 states, Canada and the District of Columbia. According to their findings, 33 of the units were contaminated with M. chimaera, and four of the units also tested positive for the bacteria that causes Legionnaire’s disease.
“Our results showed M. chimaera in 37 percent of units tested and is consistent with previous findings. The extent of contamination from such a rare organism in multiple units from all over the country was surprising,” Rihs said. “Some devices remained positive for M. chimaera for months, indicating that disinfection can be difficult and routine testing is advisable. Beyond M. chimaera, we found other NTM species, Legionella, and fungi, indicating these units are capable of supporting a diverse microbial population.”
The FDA first warned about the heart surgery infection risk from heater-cooler devices in October 2015, indicating that a large number of adverse event reports had been received in connection with the device.
In June 2016, a panel of experts were convened to evaluated the problems, indicating that at least 34 reports involving bacterial infections following heart surgery involving heater-cooler systems had been received between January 2010 and August 2015.
Late last year, the federal regulators issued a safety communication warning about the infection problems with 3T Heater-Coolers, indicating that water tanks used by the devices can become contaminated and spread contaminants to other parts of the system, where they can be released into the air.
The U.S. Centers for Disease Control and Prevention (CDC) also issued a Health Alert Network advisory over the potential risk of M. Chimaera infections following heart surgery, indicating that about 60% of the 250,000 heart bypass procedures performed each year in the United States involve use of affected 3T Heater-Cooler systems.
The FDA is now advising facilities using 3T devices to remove the devices and any accessories from service if they have tested positive for the bacteria, or have been linked to patients who later were identified as infected. The agency also recommends using new accessories, tubing and connectors if using a new heater-cooler device, channeling exhaust from the devices away from patients and into an operating room exhaust vent, and to review the recommendations in the CDC’s health advisory.”
The manufacturer, Sorin Group, currently faces a growing number of M. chimaera infection lawsuits brought on behalf of individuals who were exposed to the contaminated 3T systems. As additional infections continue to surface in the coming months and years, the number of cases is expected to continue to grow, potentially involving hundreds of claims.