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

Conventional antimicrobial therapies are less effective against pythiosis. Therefore, the goal of this study was to characterize the effects of two ozone (O-3) presentations on the growth of canine Pythium insidiosum. In Experiment 1, the pathogen was treated with O-3 gas at different concentrations (32, 52, or 72 mu g O-3 mL(-1) for 30 min) or exposure times (72 mu g O-3 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 O-3 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 O-3 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.