Ozone Gas and Ozonized Sunflower Oil as Alternative Therapies against Pythium Insidiosum Isolated from Dogs

ABSTRACT

Conventional antimicrobial therapies are less effective against pythiosis. Therefore, the goal of this study was to characterize the effects of two ozone (O₃) presentations on the growth of canine Pythium insidiosum. In Experiment 1, the pathogen was treated with O₃ gas at different concentrations (32, 52, or 72 μg O₃ mL⁻¹ for 30 min) or exposure times (72 μg O₃ mL⁻¹ for 5, 15, or 30 min). In Experiment 2, pathogen samples were covered with ozonized sunflower oil with distinct peroxide indices. The growth area of P. insidiosum was measured during the first 14 days after treatment. Samples without growth were recultured to assess the germicidal or germistatic action of the respective therapy. In Experiment 1, treatment for 30 min had germicidal action regardless of the gas concentration, whereas shorter exposures to O₃ were not effective. In Experiment 2, only ozonized sunflower oil with a peroxide index > 600 mmol equiv. kg⁻¹ inactivated the pathogen. The findings of the present study suggest that exposure to O₃ gas and ozonized sunflower oil with a high peroxide index are promising options for the long-lasting treatment of cutaneous pythiosis in humans and domestic animals.

KEYWORDS:

• Antifungal
• germicidal
• ozone therapy
• skin infection
• pythiosis

Highlights

1. Exposure of Pythium insidiosum to O₃ gas for 30 min had a germicidal action regardless of the concentration.

2. Ozonized sunflower oil with high peroxide index inactivated P. insidiosum.

3. Ozone therapy was effective against canine P. insidiosum.

Acknowledgments

The authors thank Dr. Sandra M.G. Bosco and the Biosciences Institute, UNESP, for providing precultured P. insidiosum samples. The authors thank Ozontop® (Botucatu, Brazil) and Ozone & Life® (São José, Brazil) for providing the material supplies.

Conflicts of interest

The authors declare that there are no conflicts of interest that would prejudice the impartiality of this scientific work.

Additional information

Funding

This research was financially supported by CAPES (grant numbers 2019/150.09955 and 2018/180.3574) and FAPESP (grant numbers 2019/13812-0 and 2019/15532-4).