Experts Address How Cleaning and Disinfection Strategies Can Tackle Emerging Microbial Threats
By Kelly M. Pyrek
Addressing emerging threats was the theme of the Cleaning & Disinfection Symposium held during the 2023 annual meeting of Infection Prevention & Control Canada (IPAC) late last month, with experts tackling imperatives ranging from dry surface biofilms to Candida auris infections and taking an all-encompassing approach to infection prevention. Let’s explore these emerging threats and the solutions proposed by these thought leaders.
In her presentation on dry surface biofilms, clinical microbiologist Michelle Alfa, PhD, FCCM, formerly a principal investigator at the St. Boniface Research Centre and a professor in the Department of Medical Microbiology at the University of Manitoba and presently a consultant, acknowledged that most infection preventionists know of wet biofilms and issues around sink drains, but dry biofilms are just as prevalent and problematic in healthcare settings.
For example, Nkemngong, et al. (2020) remind us that “Staphylococcus aureus and Pseudomonas aeruginosa are some of the most common causes of healthcare-acquired infections (HAIs). These pathogens can grow in the environment as biofilms. They attach to inert surfaces and can be encased by extracellular polymeric substances (EPS). Biofilms on high-touch surfaces are a known contributor to HAI infections; they are estimated to account for 65 percent and 80 percent of microbial and chronic infections, respectively. Environmental surfaces (e.g., food trolleys, hospital commodes, bed rails) and mobile patient care equipment such as blood pressure cuffs and intravenous poles support the formation of biofilms by providing a platform for the attachment of planktonic bacterial cells … Once formed, biofilms are capable of growing on dry surfaces in healthcare facilities for protracted periods, surviving for as long as one year. The definition of a DSB is controversial, as there is no clear definition or test method to differentiate varying degrees of dehydrated or dry biofilms. Dry surface biofilms (DSB) have been reported to persistently grow on contaminated environmental surfaces in healthcare facilities and can therefore play an important role in HAIs. Although dehydrated, DSB can still be characterized by the presence of EPS. At maturity, bacterial cells in P. aeruginosa and S. aureus wet surface biofilms become motile, allowing for easy dispersal and re-attachment on other surfaces.”
Notably, compared to wet surface biofilms and planktonic bacteria, DSB are more tolerant to disinfection, Nkemngong, et al. (2020) and other researchers report.
As Alfa, et al. (2019) observe, “The concept of “dry surface biofilm” was first introduced by Almatroudi, et al. to identify that hard and soft environmental surfaces within healthcare facilities are not void of organisms, but rather represent a heterogenous accumulation of organisms and other material in a dry matrix. The in vitro dry surface biofilm model that they developed mimics the characteristics of surfaces within healthcare facilities.” They state further, “The presence of dry surface biofilm formed on high-touch healthcare surfaces raises the question regarding its role in transmission of pathogens that ultimately cause hospital-acquired infections. It also raises questions regarding the efficacy of removal and inactivation of microbes within dry surface biofilm by currently used cleaning-disinfection methods routinely used in healthcare.”
Read further from the July 2023 issue HERE