Antimicrobial activity of Streptomyces species against mushroom blotch disease pathogen.

Bacterial blotch caused by Pseudomonas tolaasii is still one of the main diseases in mushroom farms. Effective treatment of the infections caused by P. tolaasii is yet to be established. The isolation and identification of three Streptomyces species that showed antimicrobial activity against P. tolaasii NCPPB 2192(T) were described. Six strains were highly active with an inhibition zone more than 20 mm in diameter. They were assigned to the known Streptomyces cluster groups as S. rochei, S. lydicus and S. antibioticus. The fermentation, preliminary extraction and isolation of bioactive components were carried out. The bioactive compound may be a beta-lactam structurally related to the penicillins.