Bacterial secondary metabolite prodigiosin inhibit biofilm development by cleaving extracellular DNA
Prodigiosin a bacterial secondary metabolite is a heterocyclic compound belongs to the class of tripyrrole, synthesized by various strains of bacteria includes Serratia species. Research on prodigiosin is under limelight for past 10 years from clinical and pharmacological aspects in relevance to its potential to be drug for cancer therapy by inducing apoptosis in several cancer cell lines. Reports suggest that prodigiosin promotes oxidative damage to DNA in presence of copper ion and consequently lead to inhibition of cell-cycle progression and inducing cell death. However, prodigiosin has not been previously implicated in biofilm inhibition. We performed experiments to reveal any link between prodigiosin and biofilm inhibition through degradation of extracellular DNA which plays a major role in biofilm establishment. Our study showed that prodigiosin (extracted from Serratia culture) has strong DNA cleaving property but does not intercalate with nitrogenous bases of DNA. Using P. aeruginosa PA14 wild-type strain as a model organism we showed that bacterial cells treated with prodigiosin showed significant reduction in its cells surface hydrophobicity and consequently affecting surface energies and physico-chemical property essential for bacterial adhesion and aggregation. We also found that prodigiosin did not influence planktonic growth of P. aeruginosa however, was successful in inhibiting the establishment of biofilms includes decrease in biofilm thickness, adhesion to substratum, decrease in biovolume, microcolony formation and also significantly dispersed pre-established biofilm of P. aeruginosa. This novel function on the biofilm inhibition of prodigiosin could be used to interfere with risks associated with bacterial biofilms.