Quantifying Cleanliness is Key to HAI Control

When scientists reach a consensus that the presence of a minute quantity of a microbe isn’t harmful to human health, such as the total microbial content threshold that a laundry’s cleaned textiles must not exceed to be TRSA Hygienically Clean certified, defending against contamination becomes more effective. This concept is rarely embraced in U.S. healthcare settings and developing more such standards is needed to combat healthcare associated infections (HAIs), a University of Arizona professor told an Association for the Healthcare Environment (AHE) seminar on Sept. 28.

Kelly A. Reynolds, who directs the environmental health sciences program at the university’s Zuckerman College of Public Health, characterized the development of low cost, rapid approaches to assess infection control interventions as a public health need. Health facilities need to adopt more quantitative microbial risk assessment (QMRA) techniques, she said. This will lead to a greater understanding of impacting relationships among:

• Hand hygiene and pathogen transmission in the healthcare environment
• Worker/patient behaviors and exposure risks
   

Pathogens survive for hours to months, depending on their original concentration, type and environmental factors. Almost 80% of infectious diseases are transmitted via touch (worker hands to patient). Even workers with no patient contact (about 40% of them) contaminate their gloves from surfaces.

Soft surfaces are recognized for potential in spreading HAIs. While linens and garments are almost never implicated in outbreaks, they can harbor pathogens. A 2006 study showed that over half of isolation room beds and mattresses tested positive for MRSA. Bacillus, pseudomonas, burkholderia and MRSA pathogens were isolated from air during linen changes in 2008 research.

Yet the correlation between pathogen presence and risk is not clear because of the lack of definitions of “clean.” In her presentation at the AHE Exchange in Pittsburgh, Reynolds pointed out that “We don’t have those kinds of standard for healthcare,” the kind that EPA sets for drinking water, USDA for food or the military for exposure to nuclear power.

With a better understanding of cleanliness, priorities can be set for interventions for risk management, but first, intervention must be planned. Studies like those described above identify and quantify hazard levels. Epidemiological studies come next, followed by modeling of pathways that microbes follow in various healthcare environments.

The drawing shown above depicts such a model. In this study, researchers seeded a virus surrogate in a wing of a skilled nursing and rehabilitation facility at a nurse’s station. They monitored the surrogate’s transfer to other locations in the wing and noted its migration to several additional locations. Although patient beds were not one of them, other soft surfaces (privacy and window curtains, chair) were.

“Soft surface control is frequently overlooked in cleaning, sanitizing and disinfection protocols,” Reynolds noted, yet a wealth of epidemiological evidence links such surfaces to infectious outbreaks. Better QMRA tools, she said, would provide healthcare professionals with data to initiate discussions of intervention options and ensure resources are used to improve healthcare quality and patient satisfaction.