The Role Of Environment In Infection Transmission

Infection Transmission

While the COVID-19 pandemic has caused a lot of societal changes, one in particular is the new way that Americans are looking at the spread of viruses and the importance of managing germs. Unfortunately, there is still a lot left to be learned about how infections spread and how we can minimize the risk of infection by keeping our environment clean.

The Problem: Nosocomial Infections

Nosocomial infections, also commonly known as Healthcare-Acquired infections (HAIs) are a multi-billion-dollar problem[1] and a leading cause of morbidity and mortality around the world. On any given day, about 1 in 31 hospital patients has at least one healthcare-associated infection, according to the Centers for Disease Control and Prevention[2]. A rise in antibiotic resistance and MDROs (Multidrug-Resistant Organisms) pose further challenges in HAIs. But there is good news. These nosocomial infections are preventable, or at least reduced significantly, by implementing infection control protocols and practices such as hand hygiene, use of personal protective equipment, and routine disinfection of surfaces, among other things.

One of the Factors: The Role of Environment and Survival of Pathogens on Surfaces

There are several environmental factors that play a role in disease transmission in healthcare settings. One of them is the ability of pathogens to survive in the environment[3] and the other is the contaminated environment acting as a reservoir and a source of an outbreak. It is found that pathogens, such as MRSA (Methicillin-resistant Staphylococcus aureus), VRE (Vancomycin-resistant enterococci), and C. diff (Clostridioides difficile) spores can survive on inanimate surfaces in the healthcare settings for long periods of time: in some instances, up to several months[4]. The survival of these pathogens on surfaces increases the risk for healthcare-acquired infections. A MRSA infection in a prior room occupant increases the next occupant’s risk of acquiring the MRSA infection by 1.5 times[5]. For VRE and C. diff the risk increases by 2.2 times and 2.5 times, respectively[6].  In another study, it is found that if the next patient occupies the same bed as the infected patient, the risk of infection by the same pathogen increases by almost 5.8 times[7]. In summary, infected patients impact outcomes of future room occupants due to contaminated surfaces in the healthcare environment.

Current Solutions: Environmental Cleaning and Common Disinfectants

Because of the importance of environment surfaces and the role they play in the transmission of infections, environmental cleaning practices for these surfaces are of the upmost importance.  The predominant practice is to disinfect healthcare surfaces, both soft porous surfaces such as patient linens, and the hard non-porous surfaces such as floors, patient bedside tables, etc., by using chemical disinfectants. The chemistry of these disinfectants is generally based on hydrogen peroxide, quaternary ammonium compounds, or chlorine. The effectiveness of these chemical disinfectants depends on the concentration, contact time with the surface, and the adequacy of cleaning before disinfection. In standard manual cleaning practices, the use of these disinfectants is prone to potential errors; lack of adherence to directions for use, incorrect dilutions, or solutions not left on surfaces for the required amount of time. Studies have shown that less than 50% of room surfaces[8] are cleaned with any regularity, and even when they are cleaned, the cleaning is inadequate. Even after post bleach cleaning, 30% to 70% of surfaces were still contaminated with pathogens.[9],[10]. In addition to manual chemical-based disinfection, there are technologies such as UV robots or hydrogen peroxide mist generators that are used in the healthcare environment, but these are predominantly used for terminal disinfection in empty patient rooms. All of these methods, including disinfectants, suffer from a serious shortcoming; they provide a one-time, short-term disinfection of the surface and do not offer continuous residual antimicrobial protection. The drawbacks of existing cleaning practices, disinfectants, and other technologies leave room for improvement and a need for new and innovative technologies for protecting surfaces.

The Fix

One of the most important actions for minimizing the role of environmental surfaces in nosocomial infections is the establishment of cleaning protocols that insure the adherence to directions for use, frequency of cleaning, disinfectant contact times, and accurate dilutions. 

Another improvement to better protect surfaces from becoming a source of nosocomial infections are chemistries that are continuously active and can provide efficacy between regular cleaning and disinfection. These types of products may reduce the level of recontamination of high touch surfaces.         The Environmental Protection Agency (EPA) divides products with residual efficacy claims into two categories: (1) disinfectants that also have residual efficacy, and (2) supplemental residual antimicrobial products that do not meet the EPA’s standard for disinfection claims but can be used as a supplement to standard disinfection practices to protect surfaces between disinfections. To date there are few products that can meet the EPA’s standard for these categories, and the few that can have drawbacks in healthcare settings. Pure copper surfaces can meet the EPA’s standard for residual antimicrobial protection, but copper surfaces are expensive, difficult to put on every surface, and prone to oxidation or leaching when treated with hydrogen peroxide or chlorine-based disinfectants.  There are quaternary ammonium products that provide up to 24 hour protection for bacteria, but these products tend to leave a sticky residue and are easily wiped off with aqueous solutions. The good news is that some companies are creating new chemistries that can provide supplemental antimicrobial protection for days and weeks. These technologies may help reduce nosocomial infections by killing pathogens that contact the surface between regular cleaning and disinfection in healthcare settings and provide protection should protocols not be followed regularly.

 Institutions concerned with the rise in HAIs may be able to reduce the risk of nosocomial infections by implementing robust infection control protocols and practices, including regular disinfection of surfaces. In addition, institutions should be aware of new technologies that offer residual disinfection and residual antimicrobial protection that can protect surfaces between regular disinfections. By practicing greater due diligence and following the science, we can minimize the spread of dangerous and deadly pathogens.

Siman Liu, a microbiology team leader for AvantGuard is a food safety specialist skilled in virology and environmental microbiology on food contact surfaces. Siman previously worked at the FDA evaluating the efficacy of dry-cleaning techniques for the removal of microbial hazards from food contact surfaces. She has an MS in Food Science from the Illinois Institute of Technology and an MS in Food Science and Human Nutrition from the University of Florida. 

Dr. Vikram K. Kanmukhla, Vice President of Technical Product Management for AvantGuard, has over 15 years of experience in innovation, quality, and product development and commercialization in startup environments. He has considerable expertise in antimicrobial chemistry and wide-ranging experience integrating antimicrobial additives into a variety of synthetic polymers such as polyester and polypropylene in medical textiles to improve patient outcomes. Dr. Kanmukhla holds nine antimicrobial patents or applications for self-sanitizing surfaces, both hard and soft and has worked extensively to obtain multiple EPA public health claims across different product and substrate categories. Prior to Avant Guard, he held key technology positions at Cupron, Cathay Pigments, NanoChemonics. Dr. Kanmukhla earned his BS in Chemical Engineering from Kevempu University, India (GPA 4.0) and a Ph.D. in Chemical engineering from Missouri University of Science and Technology. 

AvantGuard™ is creating innovative solutions that manage surfaces and provide long-term protection against viruses, bacteria, and fungi/mold, in a variety of applications. The company’s proprietary combinations of specialty molecules and polymers are customized to provide prolonged antimicrobial efficacy to a wide range of surfaces and materials.



[3] Weber DJ, Rutala WA, Miller MB, et al. Role of hospital surfaces in the transmission of emerging healthcare-associated pathogens: norovirus, Clostridium difficile, and Acinetobacter species. Am J Infect Control 2010; 38: S25–S33

[4] Kramer A., Schwebke I., Kampf G. (2006) How long do nosocomial pathogens persist on inanimate surfaces? A systematic review. BMC Infect Dis 6: 130.

[5] Huang S., Datta R., Platt R. (2006c) Risk of acquiring antibiotic-resistant bacteria from prior room occupants. Arch Intern Med 166: 1945–1951.

[6] Chemaly RF, Simmons S, Dale C, et al. The role of the healthcare environment in the spread of multidrug-resistant organisms: update on current best practices for containment. Therapeutic Advances in Infectious Disease. 2014;2(3-4):79-90. doi:10.1177/2049936114543287.

[7] Cohen, B., Liu, J., Cohen, A., & Larson, E. (2018). Association Between Healthcare-Associated Infection and Exposure to Hospital Roommates and Previous Bed Occupants with the Same Organism.       Infection Control & Hospital Epidemiology, 1-6. doi:10.1017/ice.2018.22

[8] Carling PC, Parry MM, Rupp ME, et al. Improving cleaning of the environment surrounding patients in 36 acute care hospitals. Infect Control Hosp Epidemiol 2008; 29:1035–1041

[9] KaatzGW, Gitlin SD, Schaberg DR et al. 1988. Acquisition of Clostridium difficile from the hospital environment. Am J Epidemiol 127:1289-1294.

[10] Jeanes A, Rao G, Osman M, Merrick P. 2005. Eradication of persistent environmental MRSA. J Hosp Infect 61:85-86.

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