Role of Rhamnolipids in Biofilm Formation and Velocity of Pseudomonas aeruginosa

Background: Biofilm is described as an accumulation of microbial organisms connected to a living or unmoving surface mainly through self-secreted polymeric materials. With a complete understanding of biofilm behaviors and the role of rhamnolipids in its stability or dispersion, a new path could be designed in the treatment of infections like Pseudomonas aeruginosa (P. aeruginosa). The purpose of this study was to investigate the role and function of rhamnolipids in P. aeruginosa velocity and biofilm formation ability. Materials & Methods: In this study, ۶۸ P. aeruginosa clinical samples were isolated from February ۲۰۲۲ to ۲۰۲۳ and confirmed based on culture and molecular methods. The presence of genes associated with di-rhamnolipid (rhlC) and mono-rhamnolipid (rhlA and rhlB) biosynthesis was detected by PCR method. For velocity assay, bacterial cultures on Bushnell Haas medium were monitored for ۲۴ and ۷۲ hours (۰.۵%). Findings: The results showed that the distribution of biofilm strength among P. aeruginosa strains was normal. The frequency of rhlC was significantly different from those of rhlA and rhlB (p= .۰۱). In the first ۲۴ hours, the velocity of P. aeruginosa on Bushnell Haas with glucose was ۲ µm/min and decreased during ۷۲ hours. But after ۷۲ hours, the velocity of moderate and weak biofilm-producing strains on solid medium with glycerol was constant. Conclusion: In this study, rhamnolipids produced from different carbon sources showed different behaviors on colony shape, velocity, and strength of bacterial biofilms.

Keywords:

Pseudomonas aeruginosa , Biofilm , Rhamnolipid , Velocity