Pythiosis is a harmful disease caused by Pythium insidiosum, an aquatic oomycete. Therapeutic protocols based on antifungal drugs are often ineffective because the cytoplasmic membrane of P. insidiosum does not contain ergosterol. Therefore, the treatment of pythiosis is still challenging, particularly making use of natural products and secondary metabolites from bacteria. In this study, xanthyletin and substances obtained from Pseudomonas stutzeri ST1302 and Klebsiella pneumoniae ST2501 exhibited anti-P. insidiosum activity and, moreover, xanthyletin was non-toxic against human cell lines. The hyphae of P. insidiosum treated with these three substances exhibited lysis holes on a rough surface and release of anamorphic material. Therefore, xanthyletin could be considered a promising alternative agent for treating cutaneous pythiosis in the near future.

Department of Chemistry Faculty of Science Khon Kaen University Khon Kaen Thailand

Department of Clinical Microbiology Faculty of Associated Medical Sciences Centre for Research and Development of Medical Diagnosis Laboratories Khon Kaen University Khon Kaen Thailand

Department of Microbiology Faculty of Medicine and Dentistry Palacky University Olomouc Hnevotinska 3 77515 Olomouc Czech Republic

Medical Science Program Graduate School Faculty of Associated Medical Sciences Centre for Research and Development of Medical Diagnosis Laboratories Khon Kaen University Khon Kaen Thailand

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