Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 15 3 2023 06 16 425 432 Alireza Keyhanian Infectious Diseases Research Center, Aja University of Medical Sciences, Tehran, Iran Mojgan Mohammadimehr Infectious Diseases Research Center, Aja University of Medical Sciences, Tehran, Iran Farshad Nojoomi Infectious Diseases Research Center, Aja University of Medical Sciences, Tehran, Iran Hamed Naghoosi Infectious Diseases Research Center, Aja University of Medical Sciences, Tehran, Iran Mehdi Shakouri Khomartash Medical Biotechnology Research Center, Aja University of Medical Sciences, Tehran, Iran Mohsen Chamanara Toxicology Research Center, Aja University of Medical Sciences, Tehran, Iran 2023 02 07 2023 04 30 Background and Objectives: Biosurfactants are amphiphilic surface-active agents that mainly produced by various microorganisms. In this study, the anti-biofilm and inhibition of bacterial adhesion activities of two bacterial biosurfactants were investigated. Materials and Methods: After extraction and evaluation of Bacillus cereus and Serratia nematodiphila biosurfctants, inhibition of bacterial adhesion and anti-biofilm effects of them on Staphylococcus aureus and Pseudomonas aeruginosa were determined. Results: On average, the synergistic effect of two bacterial biosurfactants, caused about 60% decrease in adhesion and about 80% decrease in biofilm formation of S. aureus and P. aeruginosa. Conclusion: The results of this study showed that combination of B. cereus and S. nematodiphila biosurfactants would increase the potential of attachment inhibition and biofilm eradication with very low toxicity. https://ijm.tums.ac.ir/index.php/ijm/article/view/4117 https://ijm.tums.ac.ir/index.php/ijm/article/download/4117/1584