IN VITRO EVALUATION OF ANTIMICROBIAL ACTIVITY AND PROBIOTIC POTENTIAL OF LACTOBACILLUS STRAINS AGAINST SOME HUMAN PATHOGENS

Objective: Curd and yogurt are the major source of probiotic consumed by majority of the Indian population and Lactobacillus spp. are the predominant bacterial species in them. The present study was carried out to isolate Lactobacillus spp, from locally available dairy products and assess for the probiotic potential. Methods: The isolated were identified using biochemical assays and assessed for the properties such as Acid tolerance, Bile tolerance and NaCl tolerance. The identified strains were also subjected to antibiotic susceptibility and Antimicrobial activity using standard methodology. Results: A total of ten Lactic acid bacteria were isolated form different sources, belonging to different Lactobacillus species viz. L. acidophilus IAMb-3, L. brevis IAMb-6, L. bulgaricus IAMb-9, L. lactis IAMb-10, L. acidophilus IAMb-11, L. fermentum IAMb-13, L. casei IAMb-14, L. casei IAMb-15, L. plantarum IAMb-16 and L. rhamonsus IAMb-18. These identified strains were able to tolerate pH-3, 0.3% bile salt and upto 5-6% NaCl. Seven out of ten stains had antimicrobial activity against the pathogenic strain used in the study. Conclusion: In the present study the some of the potential probiotic strains have been isolated from local commercial and homemade sources. The isolated strains were capable of tolerating the harsh similar to human gut environment and found antagonistic to gut pathogens, hence can considered as potential probiotics.