A mechanistic investigation into the inhibition of growth and biofilm formation in erwinia amylovora by non-protein amino acids

Abstract

Biofilms are matrix-embedded microorganisms adhering to inert or living surfaces and are impervious to drugs. Biofilm formation is partly responsible for the multidrug resistance (MDR) exhibited by human, animal and plant pathogens leading to high health costs and severe economic loss in the agricultural sector. It has been shown recently that Erwinia amylovora, the bacterium that causes fire blight, a devastating bacterial disease of pome fruit trees, forms biofilms and that biofilm formation is important for the pathogenicity of the bacterium. Existing chemical control options for fire blight have the drawbacks of resistance development and phytotoxicity. We recently undertook a screening program in an effort to find novel chemical control options for fire blight. Two compounds which are several times more active than streptomycin against both wild type and streptomycin resistant strains of the fire blight pathogen were identified in our screening program. Our investigations into the nature of biological activity of these compounds indicate that they are bactericidal in nature, inhibit growth and biofilm formation in wild type as well as resistant strains of E. amylovora and that their probable target lies in the proline biosynthesis pathway.