International Science Community Association International Research Journal of Biological Sciences 2278-3202 7 1 2018 01 10 Antagonistic effect of bacteriocin-like substances against biofilms formed by P. aeruginosa, K. pneumonia, and P. vulgaris 1 5 EN Sanchita Kar 1 Department of Microbiology, University of Chittagong, Chittagong-4331, Bangladesh Md. Nuruddin Mahmud 2 Department of Microbiology, University of Chittagong, Chittagong-4331, Bangladesh Kamrun Nahar Islam 3 Department of Microbiology, University of Chittagong, Chittagong-4331, Bangladesh Mohammad Seraj Uddin 4 Department of Microbiology, University of Chittagong, Chittagong-4331, Bangladesh > Research Paper 2017 8 21 2018 01 10 Biofilms are frequently associated with many diseases including urinary tract infections. Structural organization and chemical properties of these assorted growths of microorganisms confer them the ability to resist antimicrobial therapy and thus infections caused by these microorganisms are becoming increasingly difficult to contain. Urinary catheters are typically involved in urinary tract infections due to their susceptibility to biofilm formation. Therefore, inhibition and/ or reduction of biofilms is critical to reduce catheter-associated infections. In this study, we used bacteriocin like substances produced by Lactobacillus coryniformis and Lactobacillus casei to reduce and/ inhibit biofilms formed by several pathogenic bacteria that are frequently associated with urinary tract infections. We isolated and identified eleven biofilm-forming bacterial isolates from urinary catheters collected from hospitalized patients: five Pseudomonas aeruginosa, three Klebsiella pneumoniae, and three Proteus vulgaris. Biofilm-forming capacity of the isolates was examined using microtitre plate method and three isolates showing the strongest biofilm forming capacity were selected for further investigation. To determine the effects of bacteriocin like substances, culture free supernatants (CSF) were prepared from Lactobacillus casei and Lactobacillus coryniformis and partially purified to remove non-proteinaceous substances. The CFS and partially purified substances (PPPs) were examined against biofilms formed by the bacterial isolates. Both the CFS and PPPs reduced biofilms formed by the isolates tested in our study. Our results indicate that biofilms formed by the P. aeruginosa, K. pneumoniae, and P. vulgaris isolates were significantly reduced upon treatment with bacteriocin like substances from the lactobacilli species used in our study. Copyright@ International Science Community Association