Commonly used disinfectants varied in efficacy against Candida auris

Haq MF, et al. Infect Control Hosp Epidemiol. 2023;doi:10.1017/ice.2023.157.

Haq MF, et al. Infect Control Hosp Epidemiol. 2023;doi:10.1017/ice.2023.157.

Only a handful of commonly used disinfectants — primarily chlorine-based disinfectants — were consistently effective against the four major clades of Candida auris, researchers reported.

“Studies that have examined the efficacy of disinfectants against Candida auris have often tested a limited number of disinfectants and have not included isolates from all four major clades,” Curtis J. Donskey, MD, professor of medicine at Case Western University and staff infectious disease physician at the Louis Stokes Cleveland VA Medical Center, told Healio.

“There is concern that clade III and IV isolates may have reduced susceptibility to disinfectants, and the EPA recently published updated testing guidance recommending use of a clade IV isolate,” Donskey said.

He added that the goal of this study was to address the need for testing of a wide range of commonly used disinfectants against the four major clades of C. auris.

To do so, Donskey and colleagues tested 23 disinfectants from six disinfectant categories selected based on a survey of 57 health care facilities in 30 states. According to the study, the disinfectants were tested on C. auris test strains, including isolates from four phylogenetic clades: AR-0381 (clade II; East Asia origin), AR-0389 (clade I; South Asia origin), AR-0383 (clade III; Africa origin) and AR-0385 (clade IV; South America origin).

Overall, five chlorine-based disinfectants (Clorox Healthcare bleach germicidal cleaner, Clorox germicidal bleach wipe, Clorox Dispatch Hospital cleaner disinfectant, PDI Sani-Cloth bleach germicidal disposable wipe and Artemis BioSolutions Defender disinfectant) and the peracetic-acid-based disinfectant (EcoLab OxyCide daily disinfectant) consistently reduced all C. auris strains and C. albicans by greater than 5 log10, whereas three hydrogen-peroxide-based disinfectants reduced all the test strains by greater than 5 log10 (Clorox Healthcare hydrogen-peroxide cleaner disinfectant, Diversey Oxivir TB and PDI Sani-Hypercide).

A fourth hydrogen-peroxide-based disinfectant, Diversey Alpha HP multisurface cleaner — which reportedly has a relatively low hydrogen-peroxide concentration — did not achieve a greater than 5 log10 reduction of any of the test strains.

Additionally, two of the quaternary-ammonium-alcohol disinfectants tested (PDI Sani-Cloth germicidal wipes and Kinzua KE 15 Citrus surface disinfectant) consistently reduced all the test organisms by greater than 5 log10, whereas one other quaternary-ammonium-alcohol disinfectant (Metrex CaviCide spray) reduced only the clade II isolate by greater than 5 log10 and did not reduce the clade I, III or IV isolates.

The study also showed that none of the tested quaternary-ammonium-based products achieved a greater than 5 log10 reduction in the clade IV AR-0385 isolate, although a quaternary-ammonium disinfectant (Kinzua TB) did achieve this reduction in the clade II AR-0381 isolate.

“Many disinfectants that are commonly used in health care settings are not effective against Candida auris, and products within categories of disinfectants may vary in effectiveness,” Donskey said. “Facilities with C. auris patients should consult EPA List P, which provides a listing of products with claims against C. auris.”