Efficacy of three chemical disinfectants and steam against Clostridioides difficile endospores on nylon carpet with two different backing systems.

Abstract

Carpet could serve as a potential vehicle for transmitting Clostridioides difficile endospores, a leading cause of healthcare-associated infections. To develop carpet disinfection practices, a validated recovery method and standard efficacy testing method are necessary. The recovery method was optimized to detect C. difficile endospores on carpet by using different concentrations of Tween-80 and varying stomaching times. Adding 0.2% Tween-80 followed by stomaching for 3 min and sonication increased the recovery rate of C. difficile endospores to >60%. The efficacy of three disinfectants (two hydrogen peroxide-based products, A and B, and one chlorine-based product, C) and steam was tested against C. difficile endospores on two types of nylon carpet (with water-permeable backing and waterproof backing). The results showed that product B was the most effective among the chemical disinfectants, achieving a 5.8 and 4.9 log₁₀ CFU reduction of C. difficile endospores in 30 min on carpets with water-permeable and waterproof backings, respectively. A steam treatment of 120 s resulted in 4.9 and >6.0 log₁₀ CFU reduction on water-permeable and waterproof backings, respectively. On water-permeable backing, 30 s steam treatment followed by application of H₂O₂-based products A and B resulted in a 4.4 and >6.1 log₁₀ CFU reduction of C. difficile endospores, respectively. Overall, a 120 s steam treatment was more effective than any of the three disinfectants tested. Disinfectant efficacy varied by carpet backing type, underscoring the need for guidance in carpet selection for healthcare safety.

Importance: Clostridioides difficile, a spore-forming anaerobic bacterium and a leading cause of healthcare-associated infections, can be transmitted from the floor to other surfaces via air movement. Therefore, disinfection of all floors after cleaning, regardless of type, might be necessary to prevent recurrent C. difficile infections among patients. To develop carpet disinfection practices, a validated recovery method and standard efficacy testing method are necessary. In this study, we first optimized the spore recovery method from carpets. Next, our study demonstrated that carpet backing affected the efficacy of chemical disinfectants and steam against C. difficile endospores. Steam was particularly effective on carpets with waterproof backing, while only product B showed strong efficacy on carpets with water-permeable backing. When steam was combined with a chemical disinfectant, the efficacy of both H₂O₂-based products against C. difficile endospores was enhanced. These findings can inform the development of carpet disinfection practices.