Abstract:
Probiotics are considered to be living organisms. Which administer some kind of a health effect
on their host, when present in a significant amount. Many different genera of bacteria have
contributed to probiotics, but Lactic Acid Bacteria (LAB) are of prime importance. studies have
shown that probiotic bacteria can restore the gut flora and inhibit pathogens. Currently probiotic
role in cancer treatment is also being considered. The aim of the present study was to isolate and
characterize LAB strains from local indigenous sources and to evaluate them as potential
probiotics. Duck intestines were used as sources for isolation of these bacteria. Identification of
bacterial strains was performed by biochemical testing and Ribotyping. Survival, adhesion and
colonization were examined in gastrointestinal tract of mice. Antimicrobial activity of isolates
against STEC and Shigella was evaluated by well diffusion assay. Cytotoxic activities against
cancerous cell lines were evaluated using MTT colometric assay. Results of biochemical testing
and riboprinting revealed that isolates belong to Lactobacillus Plantarum. Rifampicin-resistant
colonies of these strains were able to be re-isolated from the faeces of mice which were fed these
probiotics ensuring their survival. The similar results of colonization were obtained in
homogenates of small intestine; large intestine and caecum of mice on the twenty-eight day after
feeding with the selected Strains. Results of antibacterial testing showed that each strain of the
probiotic bacteria had varying activity against the pathogens under similar conditions. In addition,
our findings showed a significant cytotoxic activity against HeLa cell lines. The positive results of
the study suggest that these L.Plantarum strains may be useful as potential probiotic candidates.
