A small-molecule norspermidine and norspermidine-hosting polyelectrolyte coatings inhibit biofilm formation by multi-species wastewater culture

Abstract

Norspermidine is a potent and non-bactericidal small-molecule inhibitor of biofilm growth. In this study, impacts of norspermidine on biofilm control and existing biofilm dispersal by a mixed culture from wastewater treatment systems were investigated. A surface-mediated releasing approach for prevention of bacterial biofilm formation was established via encapsulating norspermidine into polyelectrolyte multilayer coatings. Results showed that the presence of norspermidine (500-1000 μM) in medium remarkably prevented biofilm formation. Norspermidine was also effective in disassembling pre-formed biofilms. Norspermidine-containing multilayer coatings were successfully fabricated on glass slides via layer-by-layer deposition in polyethylenimine (PEI) and poly(acrylic acid) (PAA) solution. This coating exhibited a high anti-biofilm property against a mixed culture and three pure strains (Bacillus subtilis, Pseudomonas aeruginosa, and Escherichia coli). The loading amount and space distribution of norspermidine in the multilayer coating were key factors influencing its anti-biofilm efficacy. The polymer coating with norspermidine loaded in each bilayer (each-layer-type) exhibited better anti-biofilm efficacy than the bottom-type and the top-type coating, which showed a stable biofilm inhibition rate of about 60 % even after 5-day leaching in aqueous solution. Norspermidine could retard bacterial adhesion and destruct biofilm matrix by reducing exopolysaccharides and extracellular DNA (eDNA) associated with bacteria instead of growth inhibition. Norspermidine and the norspermidine-hosting coatings in this study offer a great potential for the control of biofilms in the settings of water purification and wastewater treatment systems, which shows the advantage of broad spectrum and less risk of evolved bacterial resistance compared to conventional microbicidal agents (e.g., antibiotics).

Chitosan nanoencapsulation of flavonoids enhances their quorum sensing and biofilm formation inhibitory activities against an E.coli Top 10 biosensor

“…Yet another possible target could be the phytochemicals compounds able to enhance dispersal of biofilms mainly by targeting the breakdown of the extracellular polysaccharide that makes up the extracellular matrix. Some compounds like norspermidine have been reported to have an enhanced dispersal of multispecies waste water biofilms when it was combined with silver nitrate [60,61]. To account for the enhanced inhibition observed when the flavonoids were loaded in the nanocapsules, we can argue that there is a local delivery effect, that it is enhanced at low concentrations.…”

Antiquorum sensing, antibiofilm formation and cytotoxicity activity of commonly used medicinal plants by inhabitants of Borabu sub-county, Nyamira County, Kenya

“…Another possible target site for antibiofilm activity is dispersal of biofilms mainly by targeting the breakdown of the extracellular polysaccharide that makes up the extracellular matrix. Phytochemical compounds like norspermidine have been found to possess this property [ 46 ]. Therefore, at it could be concluded that the test extracts did not possess any of these activities and therefore could not be good candidates for management of biofilms related to this test isolate.…”

Extracellular DNA in natural environments: features, relevance and applications

“…Similarly, several genes associated with the release of exDNA or with autolysis as well as quorum sensing inhibitors can be the target of an anti-biofilm therapy (e.g. Bao et al 2015; Beltrame et al 2015; Si et al 2015; reviewed by Wolska et al 2016). A nanomaterial cleaving exDNA of S. aureus biofilms was also proposed as a promising therapeutic material against biofilms (Thiyagarajan et al 2016).…”