Background: The purpose of this study was to analyze basic bactericidal and fungicidal activity of ozonated water according to EN 1040 “Chemical disinfectants and antiseptics – Quantitative suspension test for the evaluation of basic bactericidal activity of chemical disinfectants and antiseptics” and EN 1275 “Chemical disinfectants and antiseptics – Quantitative suspension test for the evaluation of basic fungicidal or basic yeasticidal activity of chemical disinfectants and antiseptics” with additional clinical multidrug-resistant bacterial strains and evaluate whether the ozonated water acts as a rapid and efficient antimicrobial agent and as such could be applied during intraoperative ozone treatment for tissue protection against infection with pathogenic bacteria.
Meterial/Methods: A prototype device for intraoperative ozone therapy was used. Besides standard bacterial and fungal strains, 60 clinical bacterial isolates were analyzed.
Results: The ozone concentration in ozonated water was sufficient to kill almost all cells of the bacterial and yeast strains tested after 30 seconds. Effective action against Aspergillus brasiliensis spores required a longer time than those required in the case of bacterial cells or vegetative cells of yeast.
Conclusions: The prototype device used in our study produced high ozone concentrations in freshly prepared ozonated water. This liquid complied with the requirements of the EN Standards: basic bactericidal and basic yeasticidal activities.

Keywords: Microbial Sensitivity Tests, Bacteria - drug effects, Aspergillus - drug effects, Anti-Infective Agents - pharmacology, Ozone - pharmacology, Water - pharmacology