In vitro evaluation of the bactericidal effect of ozonated water on multidrug-resistant shigatoxigenic Escherichia coli: a pilot study

Abstract

The bactericidal properties of ozone have been studied in the treatment of various diseases, including the prevention and treatment of mastitis. With the increase in cases of bacterial resistance and the risk to public health due to residues in milk, the search for new treatments is essential. Therefore, in this pilot study, we aimed to assess the antimicrobial effect of ozonated water against multidrug-resistant Shigatoxigenic Escherichia coli, a causative agent of bovine mastitis. For in vitro tests, three groups were evaluated at three contact times (30 seconds, 1 minute and 5 minutes). The tested groups included control (0.85% saline solution), 0.2% chlorhexidine gluconate (CHG) and ozonated water (OZO = 3.3 ± 0.4 µg/mL). After conducting the tests, the groups were assessed for colony-forming unit (CFU) counts to determine the effectiveness of each treatment. Ozonated water (OZO) demonstrated bactericidal activity statistically equivalent to that of chlorhexidine gluconate (CHG) against a multidrug-resistant Shigatoxigenic Escherichia coli strain. Therefore, it could serve as a potential alternative to antiseptics commonly used in pre-milking procedures for dairy cows.