As a follow-up to a 2015 study on presence of Pseudomonas aeruginosa in biofilm in hospital sink drains, Emilie Bédard, assistant professor at Polytechnique Montreal, and a team of researchers conducted a series of tests on the effectiveness of various drain disinfection methods, including thermal disinfection. 

Bédard presented findings from the study at the Society for Healthcare Epidemiology Association’s 2021 conference. The findings revealed that thermal disinfection using boiling temperature water was more effective than chlorine in decreasing the amount of culturable cells after application. 

The researchers worked with a multidisciplinary team that included infection preventionists, engineering technical services personnel and clinical leaders in a neonatal intensive care unit to help devise the program. 

Before applying the thermal disinfection treatment, faucets were turned on to flush the drain. A valve installed at the end of the drainpipe would cut off flow and allow the water to sit in the drain for 30 minutes once a week. The research team collected drain samples and found that thermal disinfection was a promising alternative to chlorine. 

Bédard, however, maintains that further research is still needed. 

“One of the key follow-ups for us would be to monitor this method over time and in comparison to other techniques, like vibrating drains,” she says. “We also want to work on optimizing the frequency and duration of the disinfection. We tested this every week for a half an hour, but we would like to see what happens if we go every two weeks. Or can we apply it for 20 minutes rather than half an hour?”

Another key aspect is to understand how this method will work with various materials, Bédard explains. She and the other researchers tested the method in chrome drains, which have high heat conduction properties. However, some plastic drains are not able to withstand the temperatures required for disinfection. Plastic drains that can handle higher heats, however, may experience lower surface temperatures, possibly reducing the performance of the disinfection. 

As the group continues its research, Bédard says that the hospital in which the tests were performed is looking to expand the pilot study using 16 more sinks in the neonatal intensive care unit, where patients are more vulnerable to infection.