RESUMO
AIM OF THE STUDY: In this study, antibacterial and antibiofilm potential of sulphated polysaccharides (SPs) extracted from Chlamydomonas reinhardtii (Cr) was evaluated against Neisseria mucosa, Escherichia coli, Streptococcus sp. and Bacillus subtilis. METHODS AND RESULTS: Antibacterial potential of Cr-SPs was evaluated by agar-cup diffusion, time-kill and colony-forming ability (CFU), minimum inhibitory and bactericidal concentration assays. Antibiofilm potential was evaluated by biofilm inhibition, eradication, extracellular-DNA, metabolic activity and microscopy assays. Cr-SPs at 0·5 mg ml-1 showed 34·52, 48·6, 66·1 and 55·6% reduced CFU in B. subtilis, Streptococcus, N. mucosa and E. coli respectively. Minimum inhibitory concentration of Cr-SPs was as low as 480 µg ml-1 for Streptococcus, N. mucosa and 420 µg ml-1 for B. subtilis and E. coli. At 1 mg ml-1 , Cr-SPs showed 50% biofilm inhibition, whereas 4-8 mg ml-1 showed 100% inhibition. Cr-SPs also effectively dissolved preformed biofilms. Dose-dependent reduction in extracellular DNA revealed that Cr-SPs interacts with the extra polymeric substance of the biofilm and destroys them. Light microscopy reconfirmed the above results. CONCLUSION: Cr-SPs not only inhibited biofilm formation but also effectively dissolved preformed-biofilms. SIGNIFICANCE AND IMPACT OF THE STUDY: The current study showed the promising potential of Cr-SPs as antibiofilm agents. Further validation will help in developing Cr-SPs as natural antibiotics against biofilm-causing bacteria.
