Atividade in vitro de extratos de macrofungos sobre o oomiceto patógeno Pythium insidiosum

Abstract

P. insidiosum is an etiologic agent of pythiosis, a disease that mainly affects the subcutaneous tissue of mammals that inhabit tropical, subtropical and temperate regions. The development of Pythium sp. depends on abiotic factors in the ecosystem, such as wetlands and temperature. They can be saprobes or parasites of animals and plants. In Brazil, an endemic country for the disease, horses are the most affected and treatments for pythiosis, even with the advancement of research, are still not fully established. This study evaluated the in vitro anti-P. insidiosum from aqueous, hydroalcoholic and ethanolic extracts of wild macrofungi from southern Brazil. Aqueous, ethanolic and hydroalcoholic extracts were prepared from the species Auricularia auricula, Amanita gemmata, Amanita muscaria, Gymnopilus junonius Lactarius deliciosus, Laccaria laccata, Psilocybe cubensis, Russula xerampelina. In vitro susceptibility tests were performed against 18 and 11 P. insidiosum isolates using the microdilution technique and following the M38-A2 protocol of the Clinical and Laboratory Standards Institutes (CLSI). The hydroalcoholic and ethanolic 95% extracts of R. xerampelina showed anti-P. insidiosum at minimum inhibitory concentrations that ranged from 1.87-7.50 mg/ml. And other mushroom species tested showed no inhibitory effects on the in vitro growth of P. insidiosum. This is the first study to evaluate the antimicrobial activity of mushrooms against oomycetes, showing the antimicrobial potential of the macrofungus R. xerampelina against the pathogen P. insidiosum. It is suggested that the search for other mushroom species with anti-P.insidiosum action should be expanded.