Identification of Biofilm Inhibitors from Streptomyces Strains for Reducing Pseudomonas aeruginosa Biofilm Formation

Biofilms are ubiquitous in natural, medical, and engineering environments. While most antibiotics that primarily aim to inhibit cell growth may result in bacterial drug resistance, biofilm inhibitors do not affect cell growth and there is less chance of developing resistance. This work sought to identify novel, non-toxic and potent biofilm inhibitors from Streptomyces bacteria for reducing the biofilm formation of Pseudomonas aeruginosa PAO1. Out of 4300 Streptomyces strains, one species produced and secreted peptide(s) to inhibit P. aeruginosa biofilm formation by 93% without affecting the growth of planktonic cells. Global transcriptome analyses (DNA microarray) revealed that the supernatant of the Streptomyces 230 strain induced phenazine, pyoverdine, and pyochelin synthesis genes. Electron microscopy showed that the supernatant of Streptomyces 230 strain reduced the production of polymeric matrix in P. aeruginosa biofilm cells, while the Streptomyces species enhanced swarming motility of P. aeruginosa. Therefore, current study suggests that Streptomyces bacteria are an important resource of biofilm inhibitors as well as antibiotics.

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