en بیوتکنولوژی Biotechnology پژوهشي Original Research Biofilm formation is a major determinant factor in development of bacterial infections. In addition, bacteria embedded in a biofilm are more resistant to antimicrobials and thus the ability of bacteria to persist and grow in a biofilm seems to be the major factor for pathogenesis and therapeutic failure. In the current study, a <em>Lactobacillus plantarum spp</em> was isolated from Siahmazgi cheese, traditional cheese of Guilan province, Iran, and was identified using morphological, biochemical and molecular identification assays. Antibiofilm potential of the <em>Lactobacillus plantarum</em> <em>spp</em> cell free supernatant (CFS) against multidrug resistance <em>Pseudomonas aeruginosa</em>, <em>Staphylococcus aureus</em> and <em>Escherichia coli</em> was characterized. According to the results, the CFS not only reduced biofilm formation by pathogenic bacteria, but also disrupted preformed biofilms. The CFS remained unaffected by chemicals including EDTA, SDS and Tween 80, and showed stability at high temperatures (80 and 100 ˚C), as well as a wide range of pH. However, the antibiofilm activity was inhibited after treating with proteinase K. According to these results, <em>L. plantarum</em> <em>spp</em> could be regarded as a suitable strain to produce antibiofilm agents which could be used for preventive and therapeutic approaches. Antibiofilm, multidrug resistance, lactic acid bacteria, probiotics 39 44 http://pbr.mazums.ac.ir/browse.php?a_code=A-10-99-3&slc_lang=en&sid=1 Hojjatolah Zamani h_zamani@ 10031947532846003806 10031947532846003806 Yes Department of Biology, Faculty of Science, University of Guilan, Rasht, Iran Saeid Rahbar rahbar_saeid@yahoo.com 10031947532846003807 10031947532846003807 No Young Researchers and Elites Club, Rasht Branch, Islamic Azad University, Rasht, Iran Seyed Reza Garakoui omid_112656@yahoo.com 10031947532846003808 10031947532846003808 No Section of Microbiology, Sobhan Oncology pharmaceutical company, Rasht, Iran Anahita Afsah Sahebi anahitaafsah1@gmail.com 10031947532846003809 10031947532846003809 No Department of Biology, Faculty of Science, University of Guilan, Rasht, Iran Hannaneh Jafari hana.jafari73@gmail.com 10031947532846003810 10031947532846003810 No Department of Biology, Faculty of Science, University of Guilan, Rasht, Iran