Antibiofilm Analysis, Synergistic Potential and Biocompatibility Evaluation of a Bacteriocin from Bacillus subtilis (MK733983).

This study emphasizes the potency of a bacteriocin screened from Bacillus subtilis (MK733983) of ethnomedicinal origin. Antibiofilm analysis with 0.5-3x minimal bacteriocin concentrations with critical and highly prioritized standard microbes such as Staphylococcus aureus, Mycobacterium smegmatis, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, and Chromobacterium violecium showed potential biofilm inhibition and eradication of ≥ 5-99%, ≥ 1-86% respectively that correlated with biofilm viable cell-count. The bacteriocin exhibited remarkable synergistic potential with antibiotics like Amikacin, Ampicillin, Bacitracin, Chloramphenicol, Kanamycin, Norfloxacin, Vancomycin, Tetracycline, and Streptomycin. The sum of the fractional inhibitory concentrations was less than 0.5, which corresponded to the preliminary evaluation that included disc diffusion assays and checkerboard assays. In addition to synergism, the time-kill assays revealed a 2 or 3 log10 (1000-fold) reduction, indicating bactericidal potential. Bacteriocin's effect on the growth dynamics of microorganisms has revealed its ability to intervene early and reduce microbial multiplication within 15 h of administration. Observations with a scanning electron microscope validated the antibiofilm capability. Methyl thiazol tetrazolium assay on 3T3 (normal fibroblast cell lines) up to 100 μg/ml of bacteriocin for 96 h (24 h-interval) revealed that the bacteriocin is not cytotoxic. It was also confirmed by trypan blue staining of the 3T3 cells at 96 h. Many biofilm-forming bacteria are known for causing harmful infections and resistance, and there is a growing need for new treatments. Bacteriocins are potential antibiotic alternatives, and the findings of this study are capable of being examined for larger application prospects.