01.02.24
A standard disinfecting solution for the I&I market, bleach, may not be effective against health care-associated infection (HAI) such as Clostridioides difficile infection (CDI), according to results of one UK study. Hospitals use disinfectants such as chlorine-releasing agents (CRAs) and hydrogen peroxide to decontaminate surfaces including beds, bathrooms and other areas within patient areas.
University of Plymouth researchers found sodium hypochlorite (NaOCl), commonly used as a disinfectant in healthcare settings, is ineffective in killing C dif spores. Researchers concluded that there is a growing need for disinfectants and guidelines specifically designed to combat evolving bacterial strains, considering the rising incidence of antimicrobial resistance.
The study prompts further questions about biocide tolerance within C dif and raises the issue of whether the tolerance to disinfectants is influenced by antibiotic co-tolerance.
"With incidence of anti-microbial resistance on the rise, the threat posed by superbugs to human health is increasing,” Tina Joshi, PhD, associate professor in molecular microbiology at the University of Plymouth, carried out the study with Humaira Ahmed, a fourth-year medicine student from the University’s Peninsula Medical School, said in a statement. “This study highlights the ability of C difficile spores to tolerate disinfection at in-use and recommended active chlorine concentrations. It shows we need disinfectants, and guidelines, that are fit for purpose and work in line with bacterial evolution, and the research should have significant impact on current disinfection protocols in the medical field globally.”1
The study examined the spore response of three different strains of C dif to three clinical in-use concentrations of sodium hypochlorite.
“Spores from strains R20291, DS1813, and CD630 [C difficile strains] at a concentration of 1×108 spores ml–1 were independently exposed to 1000, 5000, and 10,000 ppm,” the investigators wrote. “NaOCl in liquid form for 10 min (recommended contact time) and biocide activity was neutralized with an equal volume of 5 g l–1 sodium thiosulphate for 10 min contact time to remove any residual chlorine biocide activity.”
The spores were spiked onto surgical scrubs and patient gowns and examined using scanning electron microscopes to establish if there were any morphological changes to the outer spore coat.
Investigators reported the C dif spores were completely unaffected despite being treated with high concentrations of bleach used in many hospitals. In fact, the investigators said the chlorine chemicals are no more effective at damaging the spores when used as a surface disinfectant than when used with water with no additives.
“This study highlights the ability of C dif. spores to tolerate NaOCl disinfection at in-use recommended active chlorine concentrations,” the investigators wrote. “Understanding the molecular basis of these interactions is integral to practical management of CDI and reducing the burden of infection in health care settings.”
The investigators point out another important consideration. Specifically, there is a need to answer questions around biocide tolerance within C difficile and whether biocide tolerance is affected by antibiotic co-tolerance.
University of Plymouth researchers found sodium hypochlorite (NaOCl), commonly used as a disinfectant in healthcare settings, is ineffective in killing C dif spores. Researchers concluded that there is a growing need for disinfectants and guidelines specifically designed to combat evolving bacterial strains, considering the rising incidence of antimicrobial resistance.
The study prompts further questions about biocide tolerance within C dif and raises the issue of whether the tolerance to disinfectants is influenced by antibiotic co-tolerance.
"With incidence of anti-microbial resistance on the rise, the threat posed by superbugs to human health is increasing,” Tina Joshi, PhD, associate professor in molecular microbiology at the University of Plymouth, carried out the study with Humaira Ahmed, a fourth-year medicine student from the University’s Peninsula Medical School, said in a statement. “This study highlights the ability of C difficile spores to tolerate disinfection at in-use and recommended active chlorine concentrations. It shows we need disinfectants, and guidelines, that are fit for purpose and work in line with bacterial evolution, and the research should have significant impact on current disinfection protocols in the medical field globally.”1
Details of the Study
The study examined the spore response of three different strains of C dif to three clinical in-use concentrations of sodium hypochlorite.
“Spores from strains R20291, DS1813, and CD630 [C difficile strains] at a concentration of 1×108 spores ml–1 were independently exposed to 1000, 5000, and 10,000 ppm,” the investigators wrote. “NaOCl in liquid form for 10 min (recommended contact time) and biocide activity was neutralized with an equal volume of 5 g l–1 sodium thiosulphate for 10 min contact time to remove any residual chlorine biocide activity.”
The spores were spiked onto surgical scrubs and patient gowns and examined using scanning electron microscopes to establish if there were any morphological changes to the outer spore coat.
Investigators reported the C dif spores were completely unaffected despite being treated with high concentrations of bleach used in many hospitals. In fact, the investigators said the chlorine chemicals are no more effective at damaging the spores when used as a surface disinfectant than when used with water with no additives.
“This study highlights the ability of C dif. spores to tolerate NaOCl disinfection at in-use recommended active chlorine concentrations,” the investigators wrote. “Understanding the molecular basis of these interactions is integral to practical management of CDI and reducing the burden of infection in health care settings.”
The investigators point out another important consideration. Specifically, there is a need to answer questions around biocide tolerance within C difficile and whether biocide tolerance is affected by antibiotic co-tolerance.