Chlorine disinfectant no more effective than water in killing hospital superbugs, new study finds

One of the leading chlorine disinfectants currently used to clean hospital gowns and surfaces does not kill the most common cause of antibiotic-associated illness in health care settings globally, a new study shows.

Research carried out by the University of Plymouth showed that spores of Clostridioides difficile, commonly known as C. diff, are completely unaffected despite treatment with high concentrations of bleach used in many hospitals.

In fact, chlorinated chemicals are no more effective at damaging spores when used as a surface disinfectant than using water without additives.

Write in the journal Microbiologythe study authors say that susceptible people working and being treated in clinical parameters could, unknowingly, be at risk of contracting the superbug.

As a result, and with the incidence of overuse of biocides only fueling the increase antimicrobial resistance (AMR) worldwide, they called for urgent research to find alternative strategies for disinfecting C. diff spores to break the chain of transmission in clinical settings.

Dr Tina Joshi, associate professor of molecular microbiology at the University of Plymouth, carried out the study with Humaira Ahmed, a fourth-year medical student at the university’s Peninsula Medical School.

Dr Joshi said: “With the increasing incidence of antimicrobial resistance, the threat posed by superbugs to Human health increase. 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.

“This shows that we need disinfectants and guidelines that are fit for purpose and work in accordance with bacterial evolution, and the research is expected to have a significant impact on current disinfection protocols in the medical field globally .”

C. diff is a microbe that causes diarrhea, colitis and other intestinal complications and is known to infect millions of people worldwide each year.

It causes approximately 29,000 deaths per year in the United States and nearly 8,500 in Europe, with the most recent data showing that the incidence of C. diff infection was increasing before the start of the COVID-19 pandemic in United Kingdom.

Previously, Dr. Joshi and colleagues demonstrated the ability of C. diff spores to survive exposure to recommended concentrations of sodium dichloroisocyanurate in liquid form and in personal protective fabrics such as surgical gowns.

The new study examined the response of spores from three different strains of C. diff to three clinical concentrations of sodium hypochlorite in use. The spores were then placed on surgical gowns and patient gowns, examined by scanning. electron microscopes to determine if there have been morphological changes in the outer spore coat.

Dr. Joshi, who serves on the board of the Microbiology Society and co-chairs its Impact and Influence Committee, added: “Understanding how these spores and disinfectants interact is an integral part of the practical management of C. diff infection. and reducing the burden of infection in health care. settings.”

“However, unanswered questions remain regarding the extent of biocide tolerance within C. diff and whether it is affected by antibiotic co-tolerance. With AMR increasing globally, the “The need to find these answers – both for C. diff and other superbugs – has never been more urgent.”