Alkyl rhamnosides, a series of amphiphilic materials exerting broad-spectrum anti-biofilm activity against pathogenic bacteria via multiple mechanisms

Abstract

As novel amphiphilic materials, six uncharged alkyl rhamnosides incorporating various alkyl chain and one rhamnose amine quaternary ammonium salt were successfully synthesized in this study. Their amphiphilic properties (HLB and CMC), antimicrobial and anti-biofilm activity against S. aureus and P. aeruginosa were investigated. Differentially regulated proteins and pathways were identified by comparative proteomics research to first give a sight on how alkyl rhamnosides performed the anti-biofilm activity at protein and pathway levels. Among the uncharged alkyl rhamnosides, dodecyl rhamnoside and octyl rhamnoside showed the best antimicrobial and anti-biofilm ability against S. aureus and against P. aeruginosa, respectively. Interestingly, the relationships between amphiphilic properties or MIC with anti-biofilm activity were first established. Uncharged alkyl rhamnoside with an optimized HLB value of 5.0 had both the strongest antibacterial and anti-biofilm activity against S. aureus, and MIC was the maximum biofilm inhibitory concentration for all alkyl rhamnosides. Alkyl rhamnosides have a significant overall regulatory effect on the proteomics and pathways of bacterial biofilms, including energy production, substrates transportation, signal transduction, key molecules balance, and so on. These amphiphilic materials have a great potential to be used as additives in pharmaceutic, cosmetic, food industry, hospital and in other non-medical fields.

The Antimicrobial and Antibiofilm Activity of Oregano Essential Oil against Enterococcus faecalis and Its Application in Chicken Breast

“…As indicated by Peng et al [ 26 ], the effects of OEO on E. faecalis biofilm polysaccharides and structure were evaluated using CLSM (A1 confocal laser microscope; Nikon, Tokyo, Japan). Biofilms were produced on stainless-steel coupons (0.6 cm × 0.6 cm), as 2.7.1 described, before being treated with OEO at a concentration of 0, 4 MIC, 8 MIC, and 12 MIC at 25 °C for 1 h. The biofilms were next stained with concanavalin-A fluorescein conjugate (Con-A; Invitrogen/Molecular Probes, Eugene, OR, USA) at 4 °C for 30 min, immobilized by 2.5% glutaraldehyde for 2 h, then stained with Hoechst 33258 (Solarbio, Beijing, China) at room temperature for 20 min.…”

Inactivation of Pseudomonas aeruginosa Biofilms by 405-Nanometer-Light-Emitting Diode Illumination

“…Finally, the biofilms were washed with PBS and examined using the confocal laser microscope under a 20ϫ lens objective. Serial images were captured at 488 nm and 405 nm excitation wavelengths and processed using NIS-Elements Viewer 4.20 software (44).…”