Investigating the In Vitro Antibiofilm Potential of Lactobacillus rhamnosus

Background: Biofilms formation by pathogenic bacteria such as Escherichia coli and Staphylococcus aureus imposes clinical and economical challenges in antibiotic resistance and chronic infection. Uses of probiotics and their metabolites are emerging as promising antibiofilm strategy. Methods: Pro-baby oral drop was used to isolate the probiotics content. One ml of the formulation was cultured on de Man, Rogosa, and Sharpe (MRS) agar plate and inspected for the grown colonies. Isolated pure cultures were sent for 16s gene sequencing. Later, probiotics supernatants were prepared at three time points: 24 h, 48 h and 72 h. Antibiofilm effect of the obtained supernatants against S. aureus and E. coli biofilm was tested via 96-well microtiter plate crystal violet staining technique. Results: Two Lactobacillus rhamnosus strains were identified genetically and designated as strain A and B. Supernatants of strain A and B significantly inhibited biofilm formation, with the highest inhibition (82.1%) reported for S. aureus by 48 h-old strain A supernatant. E. coli biofilm formation was effectively suppressed (96.45%) by 72 h-old strain A supernatant. Conclusion: the study suggests that L. rhamnosus supernatants have potent antibiofilm potential against both Gram positive and Gram negative reference pathogens. This promising finding can be further investigated on in vivo infection model.