LAUSR

This study aims to explore novel LAB (Lactic acid bacteria) from breast-fed infants' feces towards characterizing their antimicrobial compound, bacteriocin. The LAB, Lacticaseibacillus paracasei F9-02 showed strong antimicrobial activity against clinical pathogens. Their proteinaceous nature was confirmed as the activity was completely abolished when treated with proteinaceous enzymes and retained during neutral pH and catalase treatment. The purified bacteriocin showed antimicrobial activity at the MIC value of 7.56 μg/mL against vancomycin-resistant Enterococcus sp. (VRE). and methicillin-resistant Staphylococcus aureus (MRSA), 15.13 μg/mL against Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella enterica subsp. enterica serotype. Typhi and 30.25 μg/mL against Shigella flexneri. Present study also proved the bactericidal, non-cytotoxic and non-hemolytic nature of bacteriocin. Additionally, bacteriocin retained their stability under various physico-chemical conditions, broad range of pH (2-10), temperature (40-121°C), enzymes (amylase, lipase & lysozyme), surfactants (Tween 20, 40, 100 & SDS), metal ions (CaCl2 , FeSO4 , ZnSO4 , MgSO4 , MnSO4 , CuCl2 ) and NaCl (2-8%). The molecular weight of bacteriocin (~28 kDa) was determined by SDS-PAGE, functional and active groups were assessed by FT-IR (Fourier Transform-Infrared) To our knowledge, this is the first study reporting L. paracasei from breast-fed infants' feces and assessing their antimicrobial compound, bacteriocin. The study results furnish the essential features to confirm the therapeutic potential of L. paracasei F9-02 bacteriocin. This article is protected by copyright. All rights reserved.