NOV 29, 2023 9:48 AM PST

Chlorine Disinfectant Is No Better at Destroying Superbug Than Water

WRITTEN BY: Carmen Leitch

Clostridioides difficile, often known as C. diff, is a dangerous microbe that can cause serious health problems in the gut such as colitis and diarrhea. Millions of people are thought to be infected by the bacterium every year, and the infections can lead to serious complications. It's estimated that almost 30,000 people in the United States and 8,500 in Europe die from C. diff infections annually. The bacterium is tough, and can be very difficult to eliminate from various settings because it forms spores. It's been thought that chlorine-based disinfectants like bleach could destroy these pathogens. However, new research has indicated otherwise.

A SEM image of Clostridium difficile bacteria. / Image credit: CDC/ Lois S. Wiggs / Photo Credit: Janice Carr

C. diff spores were found to be impervious to exposure to high concentrations of bleach, even those that are used in many hospitals. These chlorine disinfectants are often used to clean surfaces and uniforms like scrubs. But this study has shown that these cleansers are not any more effective than plain water at killing C. diff. The findings have been reported in Microbiology.

The study authors suggested that hospital staff and people working in healthcare settings could be exposed to these nasty germs without knowing. High concentrations of chlorine and biocide overuse may even be fueling a rise in bacteria that are resistant to antimicrobials. The researchers noted that it is critical for new cleaning methods to be developed and tested so that the transmission of C. diff spores becomes less likely.

"With incidence of antimicrobial resistance on the rise, the threat posed by superbugs to human health is increasing. But far from demonstrating that our clinical environments are clean and safe for staff and patients, this study highlights the ability of C. diff spores to tolerate disinfection at in-use and recommended active chlorine concentrations," said senior study author Dr. Tina Joshi, an Associate Professor in Molecular Microbiology at the University of Plymouth.

This work has shown that we need disinfectants that are up to the task of confronting the threat posed by bacteria, which evolve, and that healthcare providers must create guidelines that will effectively reduce the threat of microbial pathogens in healthcare settings.

In this study, the investigators transferred three different strains of C. diff spores onto surgical scrubs and patient gowns, then exposed them to three different concentrations of sodium hypochlorite (bleach) that are now used in clinical settings. Scanning electron microscopy was used to examine the changes in the spores. The researchers could not find any observable changes; the spores appeared to be totally unaffected by the bleach treatment. The investigators were also able to recover viable C. diff spores from surgical scrubs and patient gowns, even after they had been bleached.

There is still more to learn about whether C. diff can tolerate bleach because of something that is also related to antibiotic resistance, and it will be important to determine how spores and disinfectants might be interacting, added Joshi.

Sources: University of Plymouth, Microbiology

About the Author
Bachelor's (BA/BS/Other)
Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
Loading Comments...