Evaluation of Probiotic Characteristics of Lactobacillus gasseri HN1 Isolated from Breast Milk of Indian Mothers.

Human milk is a vital fluid that contains various nutrients and a complex bacterial community, which plays a significant role in shaping infant gut microflora. In the present study, Lactobacillus gasseri strain HN1 was isolated from the human milk of Indian healthy mothers fed on a normal North Indian vegetarian diet during the postpartum period, and its probiotics properties were evaluated. The isolated culture was identified based on its morphological and biochemical characteristics and genetic relatedness was assessed through 16S rRNA gene sequence comparison. Probiotic parameters such as tolerance to low pH, resistance to bile salt concentrations, cell surface hydrophobicity, antibiotic susceptibility, and antimicrobial activity was investigated. The strain exhibited survivability up to 3 h at pH of 2.0 and 3.0, while considerable tolerance (p < 0.05) up to 8 h at 0.5 and 1.0% bile concentration was observed. The culture exhibited substantial resistance against antibiotics such as ciprofloxacin and trimethoprim. The antimicrobial activity against S. epidermidis MTCC 9041 and S. lentus was most pronounced, with an inhibition zone of more than 25 mm. The strain exhibited β-galactosidase activity (0.5 U/mL) and possessed good adhesion potential. The results indicated that L. gasseri HN1 could be a prominent probiotic candidate to be used in the formulation of infant foods, dairy products and industrial applications. [ABSTRACT FROM AUTHOR]