Around one third of heater cooler units examined between July 2015 and December 2016 tested positive for Myobacterium chimaera, a bacteria that has been known to cause fatal infections during open-heart surgeries, according to new research presented this week.
The research was presented by Special Pathogens Lab VP of lab services John Rihs at the 44th Annual Conference of the Assocaition for Professionals in Infection Control and Epidemiology.
“These results highlight the importance of monitoring the decontamination and maintenance schedules of these devices to minimize the risk of patient harm. Hospitals must follow the cleaning and disinfection instructions provided in the manufacturer’s device labeling, as well as updated communications from the FDA and CDC,” APIC prez Linda Greene said in a prepared statement.
A total of 653 water samples from 89 different units were tested in the study, which aimed to explore the extent of colonization of the bacterium in existing devices. Samples came from 23 hospitals in 14 different states, the District of Columbia and Canada.
A total of 37% of the units tested positive for M. chimaera, while 4 units were found to be colonized with Legionella, according to the report.
Researchers also found that 97 of the cultures were deemed ‘uninterpretable’ due to high levels of bacterial and fungal contamination, with other strains of mycobacteria detected in many of the units.
“Our results showed M. chimera in 37% 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. Some devices remained positive for M. chimera for months, indicating that disinfection can be difficult and routine testing is advisable.
Beyond M. chimera, the researchers also found other non-tuberculous mycro-bacteria (NTM) species, Legionella, and fungi, indicating these units are capable of supporting a diverse microbial population. Heater-cooler units (HCUs) control the temperature of a patient’s blood and organs during heart bypass surgery. These HCUs have water tanks that provide temperature-controlled water during surgery through closed circuits.