Quorum quenching action of marine red alga Halemenia durvillei on biofilm forming Gram negative bacterial isolates from contact lens

Cell-to-cell communication among Gram negative bacteria promotes biofilm formation over implants like catheters, dental implants, contact lenses in human system, blocks drug's' action, and leads to drug resistance. Cell-to-cell communication called quorum sensing is also a problem in controlling fouling organisms. As quorum sensing leads to biofilm formation and antimicrobial resistance, attention is focused to inhibit the signal transfer. The inhibition process of quorum sensing, the synthesis of signal molecules, their action, impairment of receptor sites of signal molecules is focussed. Many natural products and their bioactive compounds disrupt or quench the quorum sensing. The quorum sensing interruption is known as quorum quenching (QQ). The inhibitors (QI) prevent biofilm formation and the development of multidrug-resistant microbes, particularly in Gram-negative bacterial pathogens. The biofilm formation by bacteria over the contact lens cause several eye infection related problems due to their multidrug resistance. So, a study was designed to identify biofilm formation inhibitors from natural products. From the contact lens, two biofilm forming Gram negative bacterial strains, Pseudomonas aeruginosa (P. aeruginosa) and Klebsiella pneumoniae (K. pneumoniae) were isolated. Against these biofilm isolates, the extracts of marine red algae Halemenia durvi-llei (HDF) were tested for quorum quenching action. The column separated HDF fraction, and its quorum quenching action on P. aeruginosa and K. pneumoniae showed a positive action. An indicator molecule, pyoverdine producing bacterial strain Pseudomonas fluorescens (PF1), was used to visualize the quorum-sensing signal conduction. Using a crystal violet stain and Congo red agar assays, the action of HDF was traced. The concentration of 60 mu g/mL of HDF, the QQ action was 54.6%, 51.8%, and 43.6% in P. aeruginosa, P. fluorescens, and K. pneumoniae, respectively. The present study results provide options to explore the bioactive molecules in H. durvi-lleii in the inhibition biofilm formation and associated drug resistance by pathogenic bacteria.

Automated summary

Cell-to-cell communication among Gram negative bacteria promotes biofilm formation over implants and leads to drug resistance. Quorum sensing interruption can inhibit biofilm formation and drug resistance. This study tested the quorum quenching action of marine red algae extract on biofilm forming bacteria and found positive results.