Attenuation of Pseudomonas aeruginosa virulence by medicinal plants in a Caenorhabditis elegans model system

Expression of a myriad of virulence factors and innate antibiotic resistance enables the opportunistic human pathogen Pseudomonas aeruginosa to create intractable infections. Using a nematode model, we screened for novel inhibitors of this pathogen. Aqueous extracts of three plants, Conocarpus erectus, Callistemon viminalis and Bucida buceras, were examined for their effects on P. aeruginosa killing of the nematode Caenorhabditis elegans. The results were evaluated in toxin-based and infection-based assays using P. aeruginosa strains PAO1 and PA14. The tested plant extracts prevented mortality via gut infection in approximately 60 % of the worms and caused a 50-90 % reduction in death from toxin production. All extracts inhibited nematode death by P. aeruginosa without host toxicity, indicating their potential for further development as anti-infectives.