Synthetic polymers capable of suppressing virulence of bacterial fish pathogens

Abstract

Biofilm production and expression of virulence factors are correlated with Quorum Sensing (QS), a density-dependent regulation of gene expression controlled by specific signal molecules produced by bacteria. Acyl-homoserine lactones (AHLs) are the most common signal molecules produced by Gram-Negative bacteria for QS. We have developed synthetic polymers that inhibit QS by sequestering the bacterial signal molecules. These synthetic polymers are methacrylate based and their composition was optimized by computer modeling. After synthesis, the binding capacity to AHLs in water was tested by equilibrium experiments and HPCL-MS. The polymers were able to absorb 0.1–0.3 mg (per gram of polymer) of 3-oxo-C6-AHL. Vibrio fischeri, that is bioluminescent through QS, was used to assess the performance of the polymers in a “real” environment. In the presence of polymers, the bioluminescence of V. fischeri was drastically reduced, without any noticeable effect on growth. In conclusion, these new polymers can sequester a signal molecule of V. fischeri and prevent QS-controlled phenotypes, thus representing a new solution for disease outbreaks in systems such as aquacultures.