The focus of the new review into the effectiveness of disinfectants in the hospital setting is with Clostridium difficile (C. diff). The organism is a Gram-positive species of spore-forming bacteria. Pathogenic C. difficile strains produce multiple toxins, and this presents a particular risk in the healthcare setting.
Concerns from the research are that the organism is winning the battle against hospital-grade disinfectants. The survival of C. diff in hospitals carries a risk due to the fact that within one month of diagnosis, one in 11 people over age 65 dies of a health care-associated C. diff infection in the U.S.
A disinfectant is a chemical that has been assessed against a standard (such as the European CEN or US AOAC) to demonstrate that the chemical is capable of reducing a population of microorganisms down to a safe level on an inanimate object (such as a bed rail or ward floor). Sometimes the word ‘sanitizer’ is used in place of ‘disinfectant’, although this causes unnecessary confusion.
Robust disinfectant efficacy testing involves challenging a range of different microorganisms (so that the spectrum of microcidal activity can be assessed) against a range of different surface materials.
According to lead researcher Professor Kevin Garey: “We found no disinfectant was able to completely eliminate C. difficile embedded within biofilms, although we did note differences among disinfectants”.
Biofilms are slime-like communities of organisms that can become embedded onto a surface. These communities provide a defence mechanism against the application of a disinfectant and pose a risk on medical devices. The centre of a biofilm is often anaerobic, which creates optimal conditions for C. diff.
The researchers found that disinfectants with the trade-names Clorox, Cidex OPA, and Virex branded disinfectants were most effective at killing C. diff spores. However, each disinfectant had limitations.
For the research, five different C. diff strains, embedded in three different biofilm types grown for 72 or 120 hours, were exposed to seven different hospital disinfectants.
The scientists hope that the research will help to improve disinfectant efficacy.
The new research is published in the journal Antimicrobial Agents and Chemotherapy, and the paper is titled “Activity of Hospital Disinfectants against Vegetative Cells and Spores of Clostridioides difficile Embedded in Biofilms.”
