Methods: We assessed 21 different germicides plus 2 dilutions of sodium hypochlorite for C. auris, Candida albicans, and Staphylococcus aureus. The disc-based quantitative carrier testing was performed to evaluate the germicidal activity of chemical germicides. An inoculum containing approximately 106 test organisms with 5% fetal calf serum (FCS) was placed on each disk. The dried inoculum was exposed to the test germicide for 1 minute exposure time at room temperature then neutralized. The log10 reduction of the test organism for each biocide was calculated and compared to mean carrier control counts.
Results: Efficacy of germicides with active ingredient, product name, and classification against C. auris, C. albicans, and S. aureus is provided in Figure 1. Our germicidal study demonstrated at least 3-log10 reduction (12/22, 55%) and 2-log10 reduction (15/22, 68%) for C. auris, 3-log10 reduction (14/22, 64%) and 2-log10 reduction (17/22, 77%) for C. albicans, and 3-log10 reduction (22/22, 100%) for S. aureus in the challenging test conditions (5% FCS and 1 minute exposure time). C. auris was less susceptible to 0.55% ortho-phthalaldehyde, 2% chlorhexidine gluconate, 4% chlorhexidine gluconate, and 1% chloroxylenol compared to C. albicans or S. aureus. C. auris was more susceptible to 70% ethanol, compared to C. albicans. Several germicides (21.7% quaternary ammonium compounds [QAC], 3% hydrogen peroxide, 5.25% sodium hypochlorite [1:50 dilution], 0.5% triclosan) had <2-log10 reduction for both C. auris and C. albicans.
Conclusion: Our preliminary study results suggest that many germicides commonly used in healthcare facilities are effective against C. auris, but further evaluations are warranted (e.g., QAC, triclosan, chlorhexidine gluconate, hydrogen peroxide) under less challenging test conditions (e.g., without 5% FCS and/or longer exposure time).
W. A. Rutala,
M. Gergen, None
E. Sickbert-Bennett, None
D. J. Weber, PDI: Consultant , Consulting fee