New Research Shows Potential of Reducing C Difficile Spores in Carpeting

Michael J. Sadowsky, PhD

A better cleaning and removal regimen of spores in carpeting and upholstery could help reduce the spread of clostridium difficile infections (CDI) in households and nursing care facilities.

A team, led by Michael J. Sadowsky, Professor, Biotechnology Institute, University of Minnesota, evaluated a fiber-safe standardized method to inhibit gemination of C difficile spores recovered from in carpeting and upholstery material to reduce the risk of disease incidence in households and nursing care facilities.

The Challenge

It can be extremely challenging to eliminate C difficile spores in carpeting and upholstery without destroying or altering the fiber matrix material. In addition, C difficile spores are highly resistant to environmental stress and common disinfectants.

“Based on our initial analyses, however, the vacuum cleaner and not solid surfaces was found to be the primary household environment contaminated with C. difficile spores,” the authors wrote. “Moreover, since carpeting is often not sufficiently cleaned, and most effective sporicides cannot be used on fibrous materials without decolorization or destruction, this may be one cause of [recurrent] CDI in household and nursing care settings.”

Finding a Way to Remove Spores

In the study, the investigators isolated C difficile strains from fecal microbiota treatment recipient households and samples containing C difficile were heat activated for 20 minutes and cultured on taurocholate-cycloserine-cefoxitin-fructose agar anaerobically for 24-48 hours.

The investigators used log reduction times for germination inhibition by different volumes of applied sporicidal solution from semi-log plots of viable spore counts/volume solution applied

The investigators identified the most effective procedures to recover C difficile spores from short-fiver textile surfaces using an ammonium phosphate-gelatin buffer, stainless steel beads to extract the spores from carpet samples, as well as the addition of a heat activation step prior to plating.

They also evaluated Virasept, a known sporicide containing hydrogen peroxide and peroxyacetic acid for marked reduction of viable C difficile spore numbers in carpet and fabric models.

After a 30 minute contact period, the investigators applied the sporicide at approximately 75 mL/m² of carpet or 51.2 mL/m² of upholstery fabric. This resulted in a 3-log reduction in germination of 5 different C difficile spores, an overall decrease of about 99.9% decrease.

The investigators also found that even after the effective inhibition of C difficile spore gemination, Virasept treatment did not visibly damage or discolor carpet or fabric fibers.

“Results of this study show the potential effectiveness of a robust regimen for the practical treatment of carpeting and upholstery fabric in nursing care facilities, and residential homes to prevent community- and environmentally-acquired reinfection and recurrence of CDI in susceptible individuals,” the authors wrote.

A Time of Need

The study comes at a crucial time when the annual incidence of CDI has increased to approximately 500,000 cases annually in the US, resulting in about 29,000 deaths. About 25% of these cases were because of community acquired infections, with the remainder coming from hospital acquired infections.

“Recently, a large proportion of C. difficile infections are due to community acquisition,” the authors wrote. “Consequently, there is a need for an easily applied solution to eradicate bacterial spores in home and nursing care settings.”

The study, “Inactivation of Clostridioides Difficile Spores in Carpeting and Upholstery to Reduce Disease Recurrence in Households and Nursing Care Facilities,” was published online in the Journal of Public Health Issues and Practices.