‘Chlorine disinfectant no more effective than water at killing superbug’

Disinfectant used in hospitals is no more effective than water at killing off a superbug, research suggests.

According to the findings, one of the main chlorine disinfectants (bleach) used to clean hospital scrubs and surfaces does not kill off Clostridioides difficile (C. diff), the most common cause of antibiotic associated sickness in healthcare settings across the world.

Research by the University of Plymouth found that spores of the bacteria are unaffected despite being treated with high concentrations of bleach.

Writing in the journal Microbiology, the scientists suggest susceptible people working and being treated in clinical settings might be unknowingly placed at risk of contracting the superbug.

With the rise in antimicrobial resistance (AMR) worldwide, the researchers are calling for urgent research to find alternative strategies to disinfect C. diff spores in order to break the chain of transmission in clinical environments.

The superbug causes diarrhoea, colitis and other bowel complications and is known to infect millions of people all over the world each year.

Dr Tina Joshi, Associate Professor in Molecular Microbiology at the University of Plymouth, said: “With incidence of anti-microbial 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.

“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.”

In the new study, scientists analysed the bacteria spore response of three different strains of C. diff to three clinical in-use concentrations of sodium hypochlorite (bleach).

The spores were then put on surgical scrubs and patient gowns, and examined using microscopes to establish if there were any changes.

The results revealed that C. diff spores could be recovered from surgical scrubs and patient gowns, with no observable changes.

This highlights the potential of these fabrics as vectors of spore transmission, researchers say.