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Poor Cleaning Can Jeopardize Sterilization of Medical Tools
Low temperature sterilization methods can create a path for transmission of bacteria 

NEW YORK (February 26, 2020) — Vaporized hydrogen peroxide (VHP) failed to completely sterilize surgical tools 76 percent of the time when the tools were soiled with salts or blood and not cleaned prior to sterilization, according to a study published today in Infection Control & Hospital Epidemiology, the journal of the Society for Healthcare Epidemiology of America.

“While sterilization technology is capable of killing billions of microorganisms on instruments, some low temperature processes are unintentionally undermined when surgical instruments are improperly cleaned before sterilization,” said William A. Rutala, PhD, MPH, director of the North Carolina Statewide Infection Control and Epidemiology Program.

Researchers at the University of North Carolina at Chapel Hill simulated the impact of proteins and salts left on surgical tools prior to sterilization to test the effectiveness of three low-temperature technologies, increasingly required for plastic tools, compared to steam sterilization.

Stainless steel test carriers, which simulated surgical tools, were soiled with salt and blood and contaminated with common bacteria found in healthcare settings — Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, vancomycin-resistant Enterococcus, Mycobacterium terrae, or spores of Bacillus atrophaeus, Geobacillus stearothermophilus, or Clostridioides difficile. The equipment was then sterilized with VHP, ethylene oxide (ETO), hydrogen peroxide gas plasma (HPGP), or steam.

VHP had the highest failure rate, 76.3 percent, with salt being the main component interfering with this technique. HPGP and ETO had failure rates of 1.9 percent. Steam sterilization, which is most common technique used for sterilization of heat-resistant instruments, was the most effective and robust sterilization technology with no failures.

“If instruments are not properly cleaned prior to sterilization and then placed in a low-temperature sterilization technology such as vaporized hydrogen peroxide, there is a possibility of failure,” Rutala said. “Effectively cleaning, removing visible soil and microbial contaminants from objects, must precede sterilization to ensure tools are thoroughly and optimally sterilized.”

The authors noted that cleaning complex medical equipment, such as surgical instruments and endoscopes with hinges, sharp bends, and lumens, present a special challenge for cleaning and sterilization as could naturally occurring biofilm build-up on medical and surgical instruments.

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William A. Rutala, Maria F. Gergen, Emily E. Sickbert-Bennett, and David J Weber. “Comparative evaluation of the microbicidal activity of low-temperature sterilization technologies to steam sterilization.” Infection Control & Hospital Epidemiology. Web (February 26, 2020).

About ICHE
Published through a partnership between the Society for Healthcare Epidemiology of America and Cambridge University Press, Infection Control & Hospital Epidemiology provides original, peer reviewed scientific articles for anyone involved with an infection control or epidemiology program in a hospital or healthcare facility. ICHE is ranked 41st out of 89 Infectious Diseases Journals in the latest Web of Knowledge Journal Citation Reports from Thomson Reuters.

The Society for Healthcare Epidemiology of America (SHEA) is a professional society representing more than 2,000 physicians and other healthcare professionals around the world who possess expertise and passion for healthcare epidemiology, infection prevention, and antimicrobial stewardship. The society’s work improves public health by establishing infection-prevention measures and supporting antibiotic stewardship among healthcare providers, hospitals, and health systems. This is accomplished by leading research studies, translating research into clinical practice, developing evidence-based policies, optimizing antibiotic stewardship, and advancing the field of healthcare epidemiology. SHEA and its members strive to improve patient outcomes and create a safer, healthier future for all. Visit SHEA online at www.shea-online.org, www.facebook.com/SHEApreventingHAIs and https://twitter.com/SHEA_Epi.

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