P034 Non-conventional alternatives to prevent Candida auris infections
Authors: Bostanaru Andra-Cristina , Nastasa Valentin , Pavlov-Enescu Carla , Hnatiuc Eugen , Mares Mihai 
Published: September 2022

Abstract

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PM

Objectives
Candida auris represents a particular organism associated with multiple nosocomial infections and high mortality rates. Appropriate infection control measures play a major role in controlling the spread and multiplication of this pathogen. Unfortunately, there are very few data available on the effectiveness of disinfectants against C. auris. Chlorine-based products appear to be the most effective for inanimate surface disinfection, while iodine-based products are more suitable for skin antisepsis. C. auris has been demonstrated to survive on dry and moist surfaces for up to 14 days, so environmental cleaning to eliminate a source of nosocomial infections is a challenge. Thus, searching for new effective fungicidal agents is still a hot topic nowadays. Non-thermal plasma-activated water (PAW) has recently emerged as a powerful antimicrobial agent, but no data about its effectiveness on C. auris are available. The aim of our study was to assess the possibility of using PAW as a fungicidal agent against C. auris planktonic cells.

Methods
PAW was prepared using distilled water and a GlidArc reactor as previously described1. The final parameters of PAW were as follows: conductivity 446 ± 25 μS/cm, pH 2.78 ± 0.12, redox potential (ORP) + 1.06 V, NO2 192 ± 10 mg/L, NO3 1550 ± 95 mg/L, H2O2 2.6 ± 0.12 mg/L, and O3 1.08 ± 0.07 mg/L.
A type strain of C. auris (CBS 10913) was used in this study. Suspensions of yeast cells (107 CFU/ml) were prepared from overnight cultures and subsequently treated with PAW in a ratio of 1:10 for different periods of time (1, 3, 5, 7, 10, 15, and 20 minutes). Precise volumes of the mixtures were further inoculated on Sabouraud Dextrose Agar plates and Bact/Alert FA Plus bottles (bioMerieux, France) in order to evaluate the reduction of yeast burden after each contact period. In addition, some instrumental analysis (IA) methods were used in order to assess the impact of PAW treatment on yeast cell structure: Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Fourier Transform Infrared Spectrometry (FT-IR), and Dynamic Light Scattering (DLS). All tests were performed in triplicates.

Results
A reduction higher than 5 log10 of viable yeast was achieved in 3 minutes. The sterilization level (i.e., ˃6 log10 reduction) was achieved after 5 minutes for the tested strain. IA clearly objectified the morphological changes in the treated yeasts compared with the untreated ones (Figs. 1 and 2).

Conclusion
Our research has successfully demonstrated the fungicidal effect of PAW against C. auris, opening a new field of research in the area of disinfectants.
1. Valentin Nastasa, Aurelian-Sorin Pasca, Razvan-Nicolae Malancus, Andra-Cristina Bostanaru, Luminita-Iuliana Ailincai, Elena-Laura Ursu, Ana-Lavinia Vasiliu, Bogdan Minea, Eugen Hnatiuc, Mihai Mares, [2021] - Toxicity Assessment of Long-Term Exposure to Non-Thermal Plasma Activated Water in Mice, Int. J. Mol. Sci., 22(21), 11 534; https://doi.org/10.3390/ijms222111534.