Method That Repels Pathogens from Hospital Surfaces Studied

Two hours’ exposure to reformulated quaternary ammonium polymer coating applied to stainless steel coupons led to a reduction in contamination of stainless steel surfaces by human coronavirus 229 E (HCoV 229 E) and SARS-CoV-2 by more than 99.9%, according to a study published in the American Journal of Infection Control.¹

“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, preautoclaved 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 HCoV 229 E and SARS-CoV-2, the virus that causes COVID-19. The study states that all work involving SARS-CoV-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 more effective.

Swabs predipped in Letheen Broth Base (LBB) 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 to 5 times using 1 mL of LBB, and then a cell scraper to detach virus further. Investigators say more studies will hopefully assess the effectiveness of the method on a variety of porous and nonporous 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, one of the study’s authors, told Infection Control Today^® (ICT^®) in May 2020 that continuously acting disinfectants will help environmental service teams keep health care facilities—and schools and office buildings—better protected from deadly pathogens.² (Gerba is the professor of microbiology and environmental sciences and a professor of public health at the University of Arizona’s Mel & Enid Zuckerman College of Public Health.)

“The problem with many disinfectants [is that] 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. 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.”

References:

1. Ikner LA, Torrey JR, Gundy PM, Gerba CP. Efficacy of an antimicrobial surface coating against human coronavirus 229E and SARS-CoV-2. Am J Infect Control. Published online September 6, 2021. doi:10.1016/j.ajic.2021.08.031
2. Diamond F. Q&A: COVID-19 will affect how environmental service teams operate. Infection Control Today®. May 20, 2020. Accessed September 28, 2021. https://www.infectioncontroltoday.com/view/qa-covid-19-will-affect-how-environmental-service-teams-operate