Horizontal Approaches to Infection Prevention

Much has been made in recent months about the outbreak of Klebsiella pneumoniae1 at the National Institutes of Health. The highly resistant organism outbreak has claimed over a dozen lives, after many months of control efforts.

By publishing their efforts, the NIH has brought into the public eye the vigilant work that goes into the fight against healthcare-associated infections worldwide. But, despite many of our dedicated and concerted efforts, these infection rates have remained essentially flat. This fact is discouraging on the surface. However, upon closer inspection, keeping HAI rates flat in the midst of a rising inpatient population of more immunosuppressed patients and an aging population should be commended. That being said, we have to do more.  

Over 100,000 deaths a year in the U.S. are caused by HAI; this number is still too high and frankly unacceptable. The essentially flat HAI rate shows that, while hand hygiene works to prevent infections, it's insufficient to the challenge. Results from a 2009, 12-month hand hygiene study2 found compliance had a baseline of 26 percent for intensive care units and 36 percent for non-ICUs. After 12 months of measuring product usage and providing feedback, compliance increased to 37 percent for ICUs and 51 percent for non-ICUs. While compliance increased when people knew they were being monitored, the report's authors noted, "[Hand hygiene] still occurs at or below 50 percent compliance for both ICUs and non-ICUs."

To get HAI rates moving downward, hospitals must incorporate layered vertical and horizontal approaches to infection prevention, in addition to high rates of hand hygiene compliance.

Vertical vs. horizontal approaches

There are basically two strategies hospitals use to combat HAIs today. Vertical strategies focus on preventing or controlling the outbreak of a single profile pathogen. However, because the effect of such a single-focused effort is limited in scope, facilities are forced to implement, manage and report the effectiveness of multiple strategies to have a meaningful impact on the HAI rate of the system. Vertical strategies provide great data, but are time consuming and may allow some pathogens to go unnoticed. Conversely, horizontal strategies use long-term techniques that address bioburden throughout the patient environment. They can be less expensive to initiate, but may not provide the same level of correlated data that vertical strategies do.

Vertical vs. horizontal is an ongoing topic of debate. Some advocates, like John Jernigan, MD, at the Centers for Disease Control and Prevention, say epidemiological characteristics of the organism must drive the interventions.3 However, as pathogens in facilities continue to increase in number and variety, Richard P. Wenzel, MD, of the Virginia Commonwealth University says vertical strategies are inherently flawed.

"Screening for methicillin-resistant Staphylococcus aureus alone made sense in the 1980s, but the ongoing emergence of vancomycin-resistant enterococci and antibiotic-resistant strains of gram-negative rods and Candida species, as well as the recognition of the value of team-based infection control programs, support a population-based approach,"4 he wrote in an article published in Infection Control and Hospital Epidemiology.

Increasingly, hospitals are looking at a cleaner patient environment as a strategy that is more cost effective and provides better overall outcomes. These include novel technological approaches that work behind the scenes such as continually active surfaces. One approach, developed in conjunction with National Health Service Infection Prevention specialists, is the Pure Hold hygiene handle. It is a germ-killing door handle for hospitals that releases a sterile sanitizer gel. It serves as convenient hospital hand hygiene for people on the move.

Other approaches have leveraged the long standing antimicrobial properties of copper, silver and other alloys. Preliminary findings of a U.S Department of Defense study demonstrate that patients treated in ICU rooms fitted with copper and copper alloy products have a greater than 40 percent reduction in risk of acquiring an infection.  

Because soft surfaces make up a large portion of the patient environment, textiles with antimicrobial properties are also being implemented. It's these surfaces that freshly washed hands often touch just before touching a patient, inadvertently transporting pathogens. This is common in the case of privacy curtains, which are known as high-touch surfaces and are also infrequently changed, unless visibly soiled.

A 2012 study published in the American Journal of Infection Control examined 43 privacy curtains and determined that 12 of the 13 curtains (92 percent) showed contamination within one week. Forty-one of 43 curtains (95 percent) demonstrated contamination at least one occasion, including 21 percent with MRSE and 42 percent with VRE (vancomycin resistant enterococcus).

While some examples of antimicrobial textiles rely on chemical coatings and topical treatments, another approach is to incorporate active ingredients into the core of the fibers themselves. One company pursuing this "imbedded" technique is PurThread Technologies. It is developing proprietary integration technology and fiber formulations for incorporating antimicrobial actives into every fiber of its fabric products at the raw material stage, for an even distribution of the active ingredient throughout the fabric.

While, PurThread's textiles are currently undergoing federal review in the United States, peer-reviewed research has demonstrated efficacy. In a double-blinded Randomized Controlled Trial conducted by the University of Iowa Carver College of Medicine, PurThread curtains withstood contamination twice as long as conventional privacy curtains (14 days, vs 7 days).  Published in the Journal of Infection Control and Prevention, the research also showed PurThread fabric was eight times more resistant the superbug vancomycin resistant enterrococus. Privacy curtains were chosen for the study because they are frequently touched by the freshly washed hands of healthcare workers before touching patients, and they often hang in place for weeks or months without being changed.

Beyond surfaces, hospitals are using ultraviolet light to kill a room full of pathogens all at once, and some studies are encouraging. One study published in PLOS Med showed installing UV lights could reduce the spread of tuberculosis in hospital wards and waiting rooms by 70 percent. Typically, UV lights can cost $3 to use per room, which can add up quickly, but it's considered cost-effective compared to automated sterilization such as hydrogen peroxide gas or mercury lamps.

Patients inevitably will contract infections in healthcare settings due to the large amount of bioburden and an increasing number of patients with compromised immune systems. Hospitals have options for both vertical and horizontal strategies to combat these HAIs, and it's up to administrators to determine which approach is best. However, to stay ahead of the curve, horizontal infection control approaches must be a part of the mix. Continuously active soft surfaces are a simple way to support the reduction of HAIs that affect hundreds of millions of people every year around the world and help healthcare workers get back to doing what they do best, putting patients on the road to recovery.


1 E. S. Snitkin, A. M. Zelazny, P. J. Thomas, F. Stock, N. C. Program, D. K. Henderson, T. N. Palmore, J. A. Segre, Tracking a Hospital Outbreak of Carbapenem-Resistant Klebsiella pneumoniae with Whole-Genome Sequencing. Sci. Transl. Med. 4, 148ra116 (2012).
2 Maryanne McGuckin, ScEd, MT et al. Hand Hygiene Compliance Rates in the United States—A One-Year Multicenter Collaboration Using Product/Volume Usage Measurement and Feedback.  American Journal of Medical Quality. March 2009.
3 Jernigan, J. (2011). Pro and Con: Strategies to Prevent HAIs: Targeting High-Risk Patient
4 Populations vs. High-Risk Pathogens. Paper presented at the Society for Healthcare Epidemiology of America (SHEA) Annual Scientific Meeting, Dallas, TX.

Thomas M. Claffey, MD has over 40 years of experience on the front line of infectious disease. Dr. Claffey is the infectious diseases director at Maine Medical Center and an Epidemiologist at Mercy Hospital in Portland, Maine. He is also the president of Intermed, a 55 physician multi-specialty group, serves on the management committee of NOVA Healthcare, and is a member of the Infectious Diseases Society of America and the American College of Physicians.

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