Effectiveness of photo-ozone therapy against equine Pythium insidiosum.

Abstract

Cutaneous pythiosis is a life-threatening infectious disease. Low-level laser therapy (LLLT) and ozone (O) have been used individually in the treatment of infected wounds. The goals of the study were a) to characterize the antimicrobial action of the photo-ozone therapy (LLLT-O) against equine Pythium insidiosum, and b) to assess the cytotoxic potential of the LLLT-Oin keratinocytes. Specimens of pathogen were isolated from 10 horses. After culturing, 120 hyphae plugs were distributed among four groups (n=30 hyphae plugs/group): LLLT (laser irradiation for 160 sec;), O(exposition to Ofor 15 min;), LLLT-O(LLLT and Otreatments in sequence) and control (untreated plugs). The hyphae growth was measured during the first 14 days post-treatment. Where there was an absence of hyphae growth, the plug was recultured for an additional 7 days. The cytotoxic potential of the treatments against HaCaT keratinocytes was assessed by colorimetric assays. The LLLT-Oand Otreatments inactivated, respectively, 92.3% (28/30) and 30% (9/30) of the samples. No growth was detected after 7 days reculture of inactivated hyphae plugs on new media. Hyphae growth was visualized in 100% of the control and LLLT hyphae plugs. The viability of HaCaT cells was not affected by the isolated treatments (LLLT and O), while the LLLT-Oshowed slight cytotoxic effect (20%) when compared to the control group (P<0.05). Photo-ozone therapy inactivated equine P. insidiosum hyphae with minimal cytotoxicity in skin cells in vitro.