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Researchers link hospital-acquired CDIs to defective cleaning solution
Outbreak investigators determined that an increase in health care-acquired Clostridium difficile infections was likely caused by a defective bleach alternative cleaning solution used to disinfect patients’ rooms, according to a recent study.
During an investigation, Jennifer L. Cadnum, BS, of Louis Stokes Veterans’ Affairs Medical Center in Cleveland, Ohio, and colleagues found that levels of peracetic acid — a substance used to kill C. difficile spores — were significantly lower than levels listed on the product label.
According to the researchers, bleach solutions are typically used to disinfect CDI isolation rooms. However, since these products can be harmful to surfaces and may cause irritation to patients and staff, some health care facilities, including the Cleveland VA Medical Center, opted to replace them with peracetic acid-based sporicidal products.
“A potential limitation of peracetic acid-based disinfectants is that they can be relatively unstable and may have a shelf life of only a few days to 3 weeks,” Cadnum and colleagues wrote. “To address this limitation, some peracetic acid-based products are activated on site by diluting a concentrated solution of hydrogen peroxide and peracetic acid. In addition, the manufacturer may recommend use of the activated product within a specified time period after activation.”
After the Cleveland VA Medical Center switched from bleach to peracetic acid-based products, the facility reported an increase in health care-acquired CDIs. When the facility switched back to bleach products, the incidence of the infections decreased.
Subsequently, an investigation was launched in March 2015 to determine the efficacy of the facility’s commercial disinfectant product, Steriplex SD (sBioMed, Orem). The solution was supplied in spray bottles or larger bottles, each of which contained a small volume of active solution sealed inside a SmartCap. In the larger bottles, a button was used to release the solution, thereby activating the product. In spray bottles, the solution was released when the top of the container was screwed into place. The shelf life of the nonactivated product was 1 year after the manufacture date; however, there was no information on shelf life after activation.
Cadnum and colleagues compared peracetic acid levels in newly activated containers that had recent manufacture dates (March 21, 2015) with those that had older manufacture dates (Oct. 23 or May 26, 2014). The researchers tested the facility’s supply of Steriplex SD, as well as a supply from a local hospital, to assess their activity against C. difficile and MRSA.
Measured concentrations of peracetic acid in Steriplex SD were between 50 parts per million (ppm) and 800 ppm, which were significantly lower than the levels indicated on the product label (1,500 ppm). The concentration levels were low in all newly activated and in-use products from the Cleveland VA Medical Center and the other local hospital. An efficacy analysis revealed that peracetic acid levels under 600 ppm did not have sufficient activity against C. difficile or MRSA.
The average concentration of peracetic acid was substantially higher in products with more recent manufacture dates that were activated upon receipt (P = .01). Their efficacy against C. difficile and MRSA was higher when tested upon activation and decreased over 6 weeks. Products with recent manufacture dates that were not immediately used had reduced concentrations and activity after activation.
“Our findings highlight the importance of conducting real-world assessments of the efficacy and active ingredient concentrations of liquid disinfectants,” the researchers wrote. “Such assessments may be particularly important if use of products requires mixing or diluting of solutions on site.”
Cadnum and colleagues submitted their results to the Environmental Protection Agency (EPA) in July 2015. The agency tested multiple products from the facility and the manufacturer and determined that the product was not effective against C. difficile. Thus, the EPA ordered the manufacturer to cease the sale, use or removal of Steriplex SD on Sept. 11, 2015. According to the manufacturer, this order affected more than 300 U.S. health care facilities.
Following its own investigation, the manufacturer suggested that the activator solution may have leaked into the container during transportation. The company reported that peracetic acid levels in containers tested prior to shipping corresponded with the levels stated on the label.
“It is plausible that use of the defective product could have contributed to the increase in the incidence of healthcare-associated CDI in our facility,” the researchers concluded. “The fact that the incidence of CDI was reduced after the switch back to a bleach product provides additional support for the hypothesis that the use of the nonsporicidal wipes might have contributed to the increase in CDI.” – by Stephanie Viguers
Disclosures: One researcher reports receiving research grants from EcoLab, GOJO, Merck and STERIS, and serves on an advisory board for 3M.
Perspective
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The article by Cadnum and colleagues is an excellent example of how an outbreak investigation is done. The identification of varying levels of peracetic acid in the commercial product suggested that was the cause of the institution’s increase in C. difficile infections. Few institutions have the resources to conduct such a detailed analysis. Products are often marketed with little objective evidence supporting their stability, shelf life and effectiveness over time. Health care product committees need to critically review a manufacturer’s data and see if the EPA has validated this information.
Disclosure: Gainer reports no relevant financial disclosures.