Efficacy of UV-C 254 nm Light and a Sporicidal Surface Disinfectant in Inactivating Spores from <i>Clostridioides difficile</i> Ribotypes In Vitro

Abstract

Clostridioides difficile is widely recognised as one of the most common causes of healthcare-associated C. difficile infections due to the ability of spores to survive for prolonged periods in the hospital environment. This study aimed to evaluate the efficacy of UV-C 254 nm light in the inactivation of the spores of different C. difficile ribotypes on brain heart infusion (BHI) agar plates or in phosphate-buffered saline (PBS) with varying spore densities. Furthermore, the effectiveness of a sporicidal surface disinfectant against C. difficile spores was determined on different surfaces. Spore suspensions of different C. difficile strains in the range of 105–107 colony-forming units (CFUs) mL−1 were inoculated on BHI agar plates or in PBS and exposed to UV-C light for up to 30 min. Additionally, a spore suspension of 103–105 CFUs was spread over a 1 cm2 test area on different surfaces, and sporicidal surface wipes were used according to the manufacturer’s instructions. The findings demonstrated that spores of C. difficile ribotypes exhibited a complete reduction in log10 CFU on BHI agar plates and PBS following 20 min of exposure to a UV-C dose of 2208 mJ cm−2. The surface wipes with sporicidal properties demonstrated efficacy in reducing the number of C. difficile spores on the Formica, stainless steel, and plastic surfaces by 2.03–3.53 log10. The present study demonstrates that moist surfaces or liquids can enhance the efficacy of UV-C treatment in reducing C. difficile spores. This approach may be applicable to the surfaces of healthcare facilities and to water disinfection systems.

Keywords

• <i>Clostridioides difficile</i>
• UV-C light
• sporicidal
• ribotypes
• disinfectant
• sporicidal surface wipes