Screening of basidiomycetes for antimicrobial activities

As a part of a screening programme developed to evaluate the antimicrobial activity of basidiomycetes, 317 isolates representing 204 species collected in Spain were screened against a range of human clinical pathogens and lab oratory controls. Extracts from 45% of the isolates, representing 109 speci es, showed antimicrobial activity. Antibacterial activity was more pronounc ed than antifungal activity. The proportion of extracts from basidiomycetes showing antimicrobial activity was similar to or above that obtained for r epresentative orders of Ascomycetes, such as Pezizales and Xylariales, but lower than that produced by members of the orders Diaporthales, Eurotiales, Hypocreales, Leotiales and Sordariales. Suprageneric taxa (orders and fami lies) did not show pronounced differences in their antimicrobial activities though such differences were observed at the genus level, suggesting that the ability to produce these bioactive compounds is not homogenously distri buted amongst the basidiomycetes. Isolates from some species showed large d ifferences in their ability to produce metabolites with antimicrobial activ ity, possibly reflecting genetic differences at the infraspecific level.