Method That Repels Pathogens from Hospital Surfaces Studied

Investigators used acetone-washed, pre-autoclaved stainless-steel coupons coated with reformulated quaternary ammonium polymer to keep deadly pathogens at bay.

Two hours of exposure to reformulated quaternary ammonium coating applied to stainless steel coupons led to a reduction in contamination to stainless steel surfaces by HCoV-229E and SARS-CoV-2 by more than 99.9%, according to a study in the American Journal of Infection Control.

“With the recent detection of infectious SARS-CoV-2 from the bedside table, remote control, bed rails, and flooring in the hospital room of an infected patient, the importance of effective hygiene protocols for environmental surfaces remains imperative,” the study states.

Investigators with the University of Arizona used acetone-washed, pre-autoclaved stainless-steel coupons coated with reformulated quaternary ammonium polymer. The uniformity of the coverage was monitored by an x-ray fluorescence spectrometer. A control group of stainless-steel coupons was not coated.

Both the control and experimental coupons were then exposed to human coronavirus 229E and SARS-CoV-2, the virus that causes COVID-19. The study states that all work involving SARS-CoC-2 was done in a Biosafety Level 3 laboratory.

The viruses were harvested using both a carrier wash method and a swab method, with the carrier wash method proving to be more effective.

Swabs pre-dipped in Letheen Broth Base were placed into tubes containing 1 mL of LBB and mixed. “The suspensions were immediately passed through Sephadex G-10 gel columns by centrifugation,” the study states. The carrier wash method involved rinsing the carriers 4–5 times using 1 mL of LBB, and then a cell scraper to detach virus further.

Investigators say that more studies will hopefully assess the effectiveness of the method on a variety of porous and non-porous surfaces.

The study states that “surface-active coatings that have antiviral capabilities are not meant to substitute for regular cleaning and disinfection practices, but rather serve as an additional barrier for reducing human exposure to infectious viruses that may be present on fomites.”

Charles P. Gerba, PhD, a professor of environmental microbiology at the University of Arizona, and one of the study’s authors, told Infection Control Today® in a Q&A in May 2020 that continuously acting disinfectants will help environmental service (EVS) teams do a better job of keeping health care facilities—and even schools and office buildings—better protected from deadly pathogens.

“What the problem is with many disinfectants, they will inactivate or kill what’s on there, but these surfaces can become contaminated right away again,” Gerba told ICT®. “And that’s the role of the continuously acting disinfecting surfaces because we know the surfaces are going to be continually contaminated all the time. I think they might play another important role too, in that we emphasize largely the high touch-areas as playing the major role in disease of infectious organisms in the spread in indoor environments, but the low-touch areas are also important. I think we ignore them a lot.”