Comparison between the effect of gentamicin and purified Lactobacillus salivarius exopolysaccharides on the biofilm formation and Pseudomonas aeruginosa Rh1I gene expression

Antibiotics have long been the only option to treat infections and biofilm inhibition. Still, in recent decades' researchers have begun to look for alternatives to them, and this study is one of the studies that look for alternatives to antibiotics. This study aimed to investigate the effect of purified Lactobacillus salivarius Exopolysaccharides (EPS) on the gene expression of the rhlI Quorum sensing gene of Pseudomonas aeruginosa compared with gentamicin. The highest L. salivarius isolates EPS production was used for isolation and purification of EPS. The sub-MIC of EPS and gentamicin was determined and used to inhibit both Pseudomonas aeruginosa biofilm and rh1I gene expression. The results revealed that OD of the biofilm before treatment is significantly higher (P < 0.001) in the P. aeruginosa isolates than after gentamicin treatment and after purified EPS treatment. Moreover, the biofilm inhibition with EPS treatment was significantly (P < 0.001) more efficient than gentamicin treatment. The rh1l gene expression in P. aeruginosa isolates after EPS sub-MIC treatment was decreased more than after gentamicin sub-MIC treatment. Depending on the results obtained, the EPS may be considered, after the performance of some toxicological tests (like MTT assay, in vivo effect of the EPS and histopathological effect), as a possible alternative to some systemic or topical antibiotics or perhaps as a preservative instead of a chemical preservative.