D-065. A Novel Method for the Inhibition of Biofilm-Producing Psuedomonas aeruginosa

M. Gavini, N. Gavini, L. Pulakat;
Mississippi State Univ., Starkville, MS.

Pseudomonas infection is a leading cause of death among patients with AIDS, Cystic Fibrosis, cancer and burn victims. These opportunistic pathogens are multidrug resistant, and produce biofilms that protect bacteria from phagocytosis and antibiotics. Treating Pseudomonas infections requires biofilm inhibitors. The aim of this research is to engineer a method to inhibit growth of biofilm-forming pathogens. Since non-biofilm forming Pseudomonas is abundant in environment, the hypothesis is that herbal products would contain biofilm-inhibiting compounds. An abiotic technique was developed to isolate a biofilm-forming Pseudomonas from the non-biofilm forming lab-stock of Pseudomonas aeruginosa PA01. The resulting clonal isolate designated Pseudomonas aeruginosa MG1could produce biofilm. Effects of ten herbal extracts/compounds on the growth of PA01 and MG1 were tested by spot testing and growth curve analysis. Terminalia chebula (Tc) extract was the most potent inhibitor of both Pseudomonas strains and was able to inhibit their growth even after over 100 fold dilution. Microarray analysis of gene expression and Real-time Polymerase Chain Reaction amplification showed that the mode of action of Tc is to reduce or inhibit the expression of genes in P. aeruginosa required for energy metabolism, adaptation, membrane transport, biofilm production, and infection of host. Thus, the results of these studies have unraveled a novel inhibitor for biofilm producing pathogens. The Terminalia chebula preparations are widely used in traditional medicines as a cleanser and immunobooster. However, there are no studies to date to examine its ability to inhibit biofilm producing pathogens. This is the first study that demonstrates Terminalia chebula extract can inhibit both the rough and mucoid forms of P. aeruginosa, and that it inhibits genes needed for the adaptation and survival of the bacteria in biofilm. The anti-microbial compound in Tc is water soluble, functional after autoclaving and at pH 7.0, and has a size <0.1 micron. It is ideal for developing anti-microbial sprays and inhalers to treat Pseudomonas infections. Author acknowledges LSBI at MSU for the generous gift of microarrays and facility.