Inhibition effects lactic acid bacteria isolated from various sources against some pathogens

In this study, by identifying the lactic acid bacteria species isolated from different sources (breast milk, feces of breast-fed babies and homemade pickles), determining the inhibition effect of the isolates against some pathogens, biofilm formation potential, antibiotic susceptibility and extracellular enzyme production capacity is intended to be determined. 46 lactic acid bacteria (LAB) were isolated 17 from breast milk, 21 from baby feces, and 8 from pickles. Among these, 10 isolates were selected to examine their characteristics, taking into account gram staining, catalase, and cell morphologies. Molecular identification of 10 selected isolates was performed by 16S rRNA gene region sequence analysis method. According to this method, we found the BST01, BST02-05, BST02-07, BST02-10, BD01-05, BD02-02 isolates are Limosilactobacillus fermentum, TU01-01 isolate is Lactiplantibacillus plantarum, BD03-01, BD04-05 isolate is Lacticaseibacillus rhamnosus, BD04-03. The BD04-03 isolate was identified as Enterococcus faecalis species. Identified isolates were registered with the National Center for Biotechnology Information (NCBI). In the agar spot test, almost all of the isolates except Lactococcus garvieae LG1 strain showed inhibitory effects against indicator microorganisms. In the well diffusion test, all isolates inhibited Pseudomonas aeruginosa isolate, except isolate BST02-07. In the cross-line test, TU01-01, BD02-02 isolates showed the highest inhibition effect against Escherichia coli. All of the isolates obtained in the study were determined to have protease enzyme activity. BST01, BST02-05, BST02-07, BD01-05 isolates were found to have moderate biofilm-forming ability. Keywords: Breast milk, baby feaces, pickles, 16S rRNA, enzyme activity